Neuropathy Resource Library

Whether your neuropathy gets worse depends far more on whether the driver damaging your nerves is still active than on the word “neuropathy” itself. That is the whole answer, and it is also why nobody can give you a timeline until the driver has been identified.

Peripheral neuropathy is the most common reason for an outpatient neurology visit in the United States and accounts for over $10 billion in health care spending each year.¹ A great deal of that reflects how long people live with a diagnosis that names the symptom rather than the cause. Progression is not one fixed path, and it is measurable.

What progression usually looks like

People usually mean symptoms when they say progression, but symptoms are only one of the things that change. Sensation, balance, strength and daily function can all shift, sometimes in different directions at once.

Length-dependent and symmetrical patterns

In many metabolic forms, the longest nerve fibers fail first. That is why symptoms typically start in the toes and move upward, and why the hands are often affected later, once the pattern has reached roughly mid-calf.

The pattern is also usually symmetrical. Symmetry points toward a systemic driver; a one-sided or patchy pattern points somewhere else entirely, which is a useful thing for your clinician to notice early.

Small fiber involvement can progress when standard testing looks normal

Burning, hot-coal sensations and altered pain and temperature perception can be present while a routine nerve conduction study looks unremarkable, because that study measures large fibers.

A normal result in that setting is not reassurance that nothing is progressing. It is a signal that the workup needs to match the symptom pattern rather than stop.

Drivers that keep progression active

Peripheral neuropathy is a category, not a diagnosis. These are the driver groups worth working through, and more than one can be present in the same person.

Metabolic injury

When glucose runs high, sugars bind to proteins in a slow browning reaction that produces advanced glycation end-products, and those accumulate in the nerve environment. Impaired flow through the small vessels that feed the nerve compounds it, because the longest fibers depend on the most fragile part of that supply.

The practical point is that while the metabolic driver runs, injury continues, whether or not symptoms happen to be quiet that week. Symptom intensity and disease activity are two different things.

Nutritional drivers

B12 deficiency can produce progressive nerve dysfunction, and it keeps producing it until the deficiency is corrected. Diet, absorption after gastrointestinal surgery, and medications that interfere with absorption all belong in the history.

Autoimmune and immune-reactive patterns

Immune-mediated processes, including gluten-related nerve injury, can drive symptoms that keep advancing while the immune activity continues. These patterns are frequently the ones sitting behind an idiopathic label.

Toxic and medication-related exposures

Chemotherapy-related nerve injury follows the exposure timeline, so the history and the symptom course have to be read together. Heavy metals such as lead, arsenic and mercury are the other exposure group worth ruling in or out when the history suggests it.

Structural compression

Not everything that looks like neuropathy is systemic. When symptoms follow the territory of a single nerve, progression may be driven by compression and local inflammation instead, which responds to entirely different treatment. The distinction is covered in nerve compression: carpal tunnel, sciatica and double-crush patterns.

Why testing changes the answer

Progression is change over time, and change over time is only meaningful against a baseline. Without one, every visit is a fresh guess about whether things are moving.

Electrodiagnostic testing (EMG/NCS) is performed on site here and characterizes large-fiber conduction. Where unsteadiness, dizziness or falls are part of the picture, VNG is used as a diagnostic test of inner-ear balance function — it is not a treatment, and it does not measure peripheral nerves.

Metabolic and nutritional assessment runs alongside both, because that is where most of the modifiable drivers actually live.

What can and cannot be promised

We do not promise that nerve damage can be regenerated or reversed. What a driver-directed plan aims at is different and more defensible: identifying what is still causing injury, reducing it where it can be reduced, and protecting function.

Symptom treatment has a place inside that. Qutenza (capsaicin 8% patch) is FDA-approved in adults only for neuropathic pain from postherpetic neuralgia and from diabetic peripheral neuropathy of the feet; use for any other driver is off-label and is described as such. It is applied in clinic by a clinician and repeated no more often than every three months.

Orthobiologic injections such as PRP and BMAC are offered in selected situations. Better sleep and less pain are worth having in their own right, but neither changes the driver.

When to be evaluated sooner rather than later

Some changes are worth acting on quickly rather than watching.

• Numbness that is spreading upward, or newly involving the hands.
• Pain that has begun disrupting sleep, or pain triggered by light touch such as a bedsheet.
• New unsteadiness, dizziness, or any fall.
• Difficulty with stairs, weakness, or a foot that catches when you walk.
• Any break in the skin, blister or hot, swollen foot when sensation is reduced.
• A high-risk history: diabetes, chemotherapy, known B12 risk, or a significant exposure.

When protective sensation is reduced, daily foot inspection stops being optional. A numb foot no longer reports injury, so the eyes have to do the job the nerves used to do.

Start with the Nerve Damage Score

The Nerve Damage Score is five questions, and it is free. It is built to point at which driver is most likely responsible in your case, which is the only honest starting point for a conversation about whether things will get worse.

Regenerve, 4477 Woodson Rd #104, St. Louis, MO 63134. Call or text (314) 886-5902, or email info@regenerve.com. We are minutes from St. Louis Lambert International Airport and see patients from across the St. Louis region, Missouri and Illinois, including Edwardsville, Glen Carbon, Collinsville, Troy and Maryville.

Frequently asked questions

My feet burn at night. Does that mean it is getting worse?

Not by itself. Night-time burning is common early and does not reliably track severity, so intensity on a given night is a poor progression measure. What matters is whether sensation, balance and function are changing over months. See small fiber neuropathy symptoms and testing.

How do clinicians predict whether neuropathy will progress?

By identifying the driver and then watching whether it is still active. A driver that is being corrected and a driver that is untouched produce very different trajectories in the same person. See the hidden drivers of peripheral neuropathy.

My blood sugar is under control now. Am I safe?

Better glucose handling reduces one source of ongoing injury, but it is not the whole terrain. Lipids, blood pressure, microvascular health, nutritional status and any additional driver all continue to matter. See diabetic peripheral neuropathy treatment in St. Louis.

What if nobody has found a cause for my neuropathy?

Idiopathic is a status, not a verdict. It usually means the workup stopped before the less common drivers were examined, including deficiency states, immune-reactive patterns and exposures. See functional B12 deficiency and neuropathy.

Could an exposure be making mine worse without my knowing?

It is possible, and it is worth ruling in or out rather than assuming. Heavy metals such as lead, arsenic and mercury are the classic example, and exposure history is often the only clue before testing. See heavy metals and neuropathy.

Sources

1. Tavee JO. Office approach to small fiber neuropathy. Cleveland Clinic Journal of Medicine. 2018;85(10):801–812. ccjm.org

Whole-body infrared delivers infrared light and radiant heat to the entire body rather than to one limb or one foot. At Regenerve it is offered as supportive care inside a plan built around the specific driver of your neuropathy — metabolic, nutritional, autoimmune, toxic or structural — and never as a treatment given on its own.

Two things are true at once, and this page holds both. Infrared therapy devices are not covered by Medicare for peripheral sensory neuropathy, so a course of it is paid out of pocket.² And the randomized evidence that determination rests on studied a different delivery method, in narrowly selected patients, for a few weeks at a time. Neither fact settles what infrared can do for a specific person, and this page explains why.

Coverage, stated plainly and then set aside

Effective October 24, 2006, the Centers for Medicare & Medicaid Services determined that infrared therapy devices and related accessories are not reasonable and necessary under section 1862(a)(1)(A) of the Social Security Act. Infrared and near-infrared light and heat, including monochromatic infrared energy, is nationally non-covered for diabetic and non-diabetic peripheral sensory neuropathy, for wounds and ulcers of the skin and subcutaneous tissues, and for symptoms such as pain arising from those conditions. The policy is recorded as national coverage determination 270.6, implemented January 16, 2007.²

You should know this before you start anything, because it decides how the service is paid for. Patients sign an advance beneficiary notice for non-covered services and pay out of pocket. Anyone offering you infrared for neuropathy who implies it will be billed to Medicare is either mistaken or misleading you.

What a coverage determination is not is a clinical finding about your nerves. It is a program’s decision about what it will purchase, made under a legal standard, at a fixed point in time, on the evidence available then. That is a legitimate and important decision, and it is a different question from whether a therapy helps a particular person with a particular driver. The rest of this page deals with the clinical question.

“Infrared” names two different things

The word covers a wide band, and the distinction is not cosmetic. It decides which studies apply to what you are being offered.

Contact pad devices

These are arrays of infrared diodes mounted on flexible pads that are strapped against the skin of the foot and lower leg. This is the device the 2006 coverage determination describes and regulates, under the durable medical equipment benefit category.² It is also, with very few exceptions, what the randomized neuropathy literature studied. In this field the technique is usually called monochromatic infrared energy.

Whole-body radiant infrared

This is a cabin or enclosure that raises body temperature with radiant infrared. There is no pad, no fixed wavelength delivered to a target tissue, and a very different dose to a very different volume of tissue. In regulatory terms, infrared lamps emit across roughly 700 to 50,000 nanometers and are intended to provide topical heating.³

When you are comparing what is on offer, ask which of these two you are actually buying. A study of pads at 890 nanometers on the sole of a foot does not automatically describe a warm cabin, in either direction.

What the randomized trials found, and who was in them

A 2017 systematic review and meta-analysis in the Brazilian Journal of Physical Therapy pooled six randomized controlled trials, 304 patients with diabetic sensorimotor polyneuropathy, and 594 feet.⁴ It is the most useful single place to see this body of work, and its own rules define the boundary of what it can speak to.

The review included randomized trials of light-emitting diodes in the 750 to 1300 nanometer range. It excluded, by rule, any trial in which the intervention was applied to a region other than the feet, and any trial with fewer than three days of intervention.⁴ Every device in it was a pad set placed on the foot and lower leg, at 870 to 890 nanometers, delivering 1.30 to 1.95 joules per square centimeter per minute. Follow-up ran from one and a half to twelve weeks, with a median of four weeks.⁴

The pooled result

Across four trials and 402 feet, infrared did not increase the number of plantar regions sensitive to the 5.07 monofilament compared with control: standardized mean difference 0.22, 95% confidence interval −0.07 to 0.51.⁴ A subgroup with follow-up of two weeks or less did show a gain, standardized mean difference 0.41, 95% confidence interval 0.18 to 0.64, and that gain was not present beyond two weeks, standardized mean difference −0.12, 95% confidence interval −0.50 to 0.26. The difference between those subgroups was itself statistically significant at p = 0.02.⁴

For pain, once a non-blinded trial was set aside, pain fell less in the infrared groups than in the sham groups: mean difference 0.40 points, 95% confidence interval 0.30 to 0.68.⁴ The review’s authors offer a specific reading of that, which is worth knowing: in a nerve that is losing fibers, restoring some sensitivity can restore the ability to feel pain, and falling pain scores in this disease are not always good news.⁴ Using the GRADE system, the authors rated the overall certainty of evidence as low for both outcomes, meaning further studies are likely to change the estimate.⁴

The largest and longest of the trials

A 2008 double-blind, sham-controlled trial in Diabetes Care randomized 69 people with diabetes; 60 patients and 120 limbs completed. Units were used at home for 40 minutes a day for 90 days. The investigators measured nerve conduction velocities, vibration perception threshold, four grades of Semmes-Weinstein monofilament, the Michigan Neuropathy Screening Instrument, a 10 cm visual analog pain scale and a neuropathy-specific quality of life instrument. There were no significant differences between active and sham on any of them.⁵

The eligibility rule that matters here is explicit in the published report: entry required a vibration perception threshold between 20 and 45 volts.⁵ That is a severity band. People with milder loss below that band, and people with the most profound loss above it, were not enrolled. We were not able to obtain the full eligibility list from the publisher, so we do not describe further exclusions beyond the one the report states.

The trial where both groups improved

A 2005 randomized, double-blind, placebo-controlled study in Diabetes Care followed 39 subjects with diabetic peripheral neuropathy through 30 minutes of active or placebo infrared three times a week for four weeks, then four weeks with no treatment. The number of sites sensing the 5.07 monofilament rose significantly in both the active and the placebo groups, and there were no significant differences between the groups at any measurement point.⁶

The Medicare review of this trial recorded the size of that placebo movement: about +0.37 sites in the active arm and +0.57 sites in the sham arm over the blinded phase, roughly 39% and 40% above baseline.³ This is the single most useful thing in the whole literature. It is why a clinic showing you before-and-after numbers with no control group has shown you nothing, and it applies to enthusiastic reports about any modality, not only this one.

The trial that separated symptoms from structure

A 2021 randomized sham-controlled study in Neurology India enrolled 38 participants with type 2 diabetes and painful diabetic peripheral neuropathy; 30 completed. Treatment was three times a week for 12 weeks, with intraepidermal nerve fiber density measured on 3 mm skin punch biopsy at baseline and at 12 weeks. Mean age was 59.1 years, mean diabetes duration 12.9 years, and mean symptom duration 3.9 months.⁷

Nerve fiber density did not increase with treatment. Pain did move: median visual analog scale decline of 5.1 points with infrared against 3.0 points with sham, intergroup p = 0.01, with a quality of life difference on the Norfolk instrument at p = 0.021. The authors concluded that infrared does not increase nerve fiber density over short-term use, but does provide symptomatic benefit and improved quality of life.⁷

This is the most informative single trial for a patient deciding what to expect, and it is also the clearest example of a narrow population. Mean symptom duration was under four months. People with years of symptoms, people with type 1 diabetes, and people whose neuropathy is not diabetic at all were not in it.

The smallest of the randomized trials

A 2011 single-blinded randomized controlled trial in the Singapore Medical Journal studied 30 feet from 24 patients, randomized to 12 daily infrared or sham treatments, with current perception threshold measured by neurometer at 2,000 Hz, 250 Hz and 5 Hz, reassessed at six weeks and three months. No significant difference was found between the infrared and sham feet.⁸ The published report does not state a full exclusion list that we could obtain.

The other side of the argument

A 2023 systematic review in Current Diabetes Reviews took a wider view of photobiomodulation in diabetic peripheral neuropathy. Across eight included studies in people with type 2 diabetes, it reported improvement in neuropathic pain and in nerve conduction velocity, along with reduced plantar pressure distribution, and its authors concluded that photobiomodulation is an effective, non-invasive option in this condition.⁹

That conclusion is real and it belongs on this page. So does its basis: the review deliberately included both randomized and non-randomized studies,⁹ and uncontrolled designs are exactly where the placebo movement described above does its damage. It is a narrative synthesis rather than a pooled estimate, and it is confined to type 2 diabetes. A reader is entitled to weigh it. A reader is not entitled to be told it settles the question.

Two independent groups have registered protocols for new systematic reviews in this area, one published in BMJ Open in 2022 and one in PLOS ONE in 2024, both specifying randomized trials, pain as a primary outcome, and nerve conduction, sensation, quality of life and adverse events among the secondary outcomes.¹¹⁰ Protocols describe what a good answer would look like. They are not themselves answers. But two of them, registered fifteen years after a coverage determination, are a fair signal that researchers consider the question open rather than closed.

What the 2006 decision was actually based on

Coverage decisions are documents, and this one is public. Reading it is more useful than repeating its conclusion.

Before the analysis there was no national determination on these devices; local Medicare durable medical equipment contractors already carried identical non-coverage policies. In the peripheral neuropathy literature, the analysis identified 14 studies, of which 11 had an infrared monotherapy arm. Only three of those were placebo-controlled with a contemporaneous parallel group. All three were double-blinded and used sham devices, and they enrolled 18, 43 and 50 patients respectively.³

The blinded treatment periods in those three trials were two weeks in one and four weeks in the other two. Between them they tested only two wavelengths, 890 and 905 nanometers. No investigator carried out dose-ranging for energy density, frequency of dosing or duration of dosing, and none varied pulsatility or duty cycle. None assessed long-term durability of any effect. None used hard clinical endpoints such as ulceration or amputation rate.³ The analysis stated that despite an exhaustive search it identified no high-quality randomized phase III trials with hard clinical endpoints, and that a major placebo effect precluded confident interpretation of the many studies in which patients served as their own controls.³ It also noted that two large trials were then in progress and could not be reviewed because they were not yet complete or published.³

That is a defensible decision on that record. It is also a decision about three small, short, single-wavelength trials of a contact pad device.

What has changed since

Four of the six trials in the 2017 meta-analysis were published after the determination took effect.⁴ Trial durations extended from four weeks to 90 days⁵ and to 12 weeks.⁷ Outcome measures widened from monofilament counts to nerve conduction velocity and quality of life⁵ and then to intraepidermal nerve fiber density on skin biopsy.⁷

The overall picture did not reverse. The pooled estimate for sensation remains null with low certainty, and the pain estimate does not favor infrared.⁴ The genuine additions on the other side are a symptom and quality of life signal without a structural change,⁷ and a narrative review reporting benefit from a mixed body of randomized and non-randomized studies.⁹

What has not changed

The coverage policy itself. The public record for national coverage determination 270.6 shows maintenance updates for ICD-10 coding in 2015 and 2017 with no policy change, and states that the determination was last reviewed in November 2006.² Anyone claiming a recent shift in Medicare’s position on infrared for neuropathy is describing something that is not in the record.

Three research gaps also remain exactly where they were. There is still no phase III trial with hard clinical endpoints. There is still no dose-ranging study establishing what energy density, session length or course length would even be the right thing to test. And there is still no randomized trial of whole-body delivery in peripheral neuropathy at all — the pooled review excluded application to any region other than the feet as a matter of its own eligibility rules.⁴

That last point needs saying carefully, because it is easy to abuse in both directions. An absence of trials of whole-body infrared is not evidence that whole-body infrared works. It is also not what the null pad-device results measured. It is a gap, and a gap is a reason for modest expectations and honest conversation, not a reason for confidence either way.

The patients these trials did not study

Randomized trials earn their authority by controlling variation, and they control it by selecting who gets in. That selection is visible in this literature wherever the reports state it.

• A severity band. The 90-day home-use trial required a vibration perception threshold between 20 and 45 volts.⁵ Milder and more profound loss were both outside it.
• A region rule. The 2017 meta-analysis excluded any trial applying the intervention outside the feet, and any trial shorter than three days.⁴
• An early-symptom population. The nerve fiber density trial enrolled people with a mean symptom duration of 3.9 months and a mean diabetes duration of 12.9 years, all with type 2 diabetes.⁷
• One form of diabetes. The 2023 photobiomodulation review was restricted to type 2 diabetes.⁹

For several of these trials the complete eligibility and exclusion list was not obtainable from the publisher. Where that is the case we have not guessed at exclusions, and this page does not assert any criterion a report does not state.

What is verifiable is what the designs did not test. None of these trials studied infrared in someone whose insulin resistance was being actively treated, whose B12 deficiency had just been corrected, whose autoimmune driver had been identified, or whose toxic exposure had been removed. None enrolled a person carrying several drivers at once alongside a long medication list. And every one of them tested infrared alone against a sham, on a fixed schedule, for a few weeks.

So a null result in a selected population, for one modality used by itself, for a short period, tells you what it tells you: that this device, at these settings, in these people, over this interval, did not beat sham on these measures. It does not establish what happens in the patients who were screened out, and it does not describe a therapy used as one element of a plan rather than as the plan. That is the ordinary difference between efficacy under trial conditions and effectiveness in practice.

It cuts both ways, and we say so. The same reasoning that stops a null trial from closing the question also stops it from being a license to assume benefit. Where nobody has measured, nobody knows.

Heat, circulation and what is genuinely established

There is a real reason clinicians are interested in heat and blood flow, and it is separate from the neuropathy trials above.

What the heat therapy evidence shows

A 2021 systematic review and meta-analysis in Experimental Physiology pooled 15 studies of heat therapy in healthy and clinical populations, with exposures of 30 to 90 minutes over 10 to 36 sessions. Compared with control, heat therapy reduced mean arterial pressure by 5.86 mmHg, systolic blood pressure by 3.94 mmHg and diastolic blood pressure by 3.88 mmHg, and improved brachial artery flow-mediated dilatation by 1.95%. Resting heart rate was unchanged. Certainty was rated moderate for the blood pressure outcomes and low for mean arterial pressure and flow-mediated dilatation.¹¹

Those are cardiovascular outcomes in a body of work about heat therapy broadly. Not one of them is a nerve measurement. It is a reasonable mechanistic reason to be interested in whole-body heat for people whose neuropathy has a microvascular component, and it is not evidence of nerve benefit. We do not present it as such and neither should anyone else.

The vasa nervorum question

Peripheral nerves are fed by very small vessels, the vasa nervorum, and the longest nerves in the body depend on the most fragile end of that supply. Oxygen delivery is a genuine bottleneck in metabolic neuropathy, which is why interventions that change local blood flow attract attention.

Warmth causes vasodilation. That much is uncontroversial. Whether raising whole-body temperature on a schedule produces a durable change in nerve function is a different claim, and it has not been established in a randomized trial in this condition.

Metabolic stress

Infrared is sometimes described as modulating metabolic stress in nerve tissue. We have not located trial evidence testing that claim in people with peripheral neuropathy, so we do not make it, and we do not use it as a reason to defer the metabolic and nutritional work that does have evidence behind it.

Safety when protective sensation is reduced

This is not a theoretical concern and it is specific to heat.

Insensitivity in diabetic peripheral neuropathy increases the risk of burns, injuries and foot ulceration.¹² The mechanism is simple: the warning system that tells you something is too hot is the same system the disease has damaged. In the infrared literature itself, the Medicare review recorded that two patients in one trial incurred superficial burns under the device pads.³

That is why heat-based therapy in neuropathy belongs under clinical supervision, with skin inspected before and after sessions, with session parameters set by someone who has measured how much sensation you have lost, and with a low threshold for stopping. It is also why a home device bought online, used by a person who cannot feel a burn forming, is a different risk profile from a supervised session.

Where whole-body infrared sits in a plan at Regenerve

Regenerve is directed by Dr. Gurpreet Singh Padda, MD, MBA, MHP. Whole-body infrared is one of the modalities available here, alongside class 4 photobiomodulation, class 3B cold laser, and metabolic and nutritional care. Electrodiagnostic testing (EMG/NCS) is performed on site. VNG is used as a diagnostic test of inner-ear balance function when unsteadiness is part of the picture; it is a test, not a treatment.

None of it is prescribed before the driver is mapped. Peripheral neuropathy is a category, not a diagnosis, and the sequence matters more than the equipment list — a point covered in the hidden drivers of peripheral neuropathy.

What we tell patients about infrared specifically

We tell them the coverage status, so there is no billing surprise. We tell them the trial evidence is for a pad device on the feet, that it is null on sensation over the durations studied, and that the one trial measuring nerve fiber density found no structural change while reporting symptom and quality of life benefit. We tell them no randomized trial has studied the whole-body form at all. We describe what we expect it to contribute — comfort, warmth, tolerance for the activity and metabolic work that carry the plan — and we say plainly that we are not claiming it repairs nerves.

We set a review point before starting, we agree on what would count as a change, and we stop if nothing changes. We do not promise that nerve damage can be regenerated or reversed, and we publish no success rate for any Regenerve protocol.

“My ethos is to treat all of my patients as I would my own family, with the goal of giving them back their quality of life.” — Dr. Gurpreet Singh Padda, MD, MBA, MHP

Questions worth asking before starting a course

• Is this a contact pad device at a stated wavelength and dose, or whole-body radiant heat? The published trials are about the first one.
• How was my neuropathy driver identified before this was recommended, and what testing was used?
• What outcome will be measured, with what instrument, and at what interval?
• How is my reduced ability to feel heat being accounted for in the protocol, and who inspects my skin?
• Is this being offered as one part of a plan, or as the plan?
• What is the review point, and at what stage do we stop?
• Am I signing an advance beneficiary notice, and what will I owe?

Start with the Nerve Damage Score

The Nerve Damage Score is five questions and it is free. It points to which driver to chase first, which is the only thing that makes any decision about infrared meaningful.

Regenerve, 4477 Woodson Rd #104, St. Louis, MO 63134. Call or text (314) 886-5902, or email info@regenerve.com. We are minutes from St. Louis Lambert International Airport and see patients from across the St. Louis region, Missouri and Illinois, including Edwardsville, Glen Carbon, Collinsville, Troy and Maryville.

Frequently asked questions

Is whole-body infrared therapy proven to treat peripheral neuropathy?

Not in the sense of a proven treatment. The randomized trials in this area studied contact pad devices on the feet and lower legs, and a 2017 meta-analysis of six of them found a short-term gain in monofilament sensation that was not sustained, on low-certainty evidence. No randomized trial has tested whole-body delivery in peripheral neuropathy, so for that specific form there is an evidence gap rather than a negative finding. Medicare has classified infrared therapy devices as non-covered for peripheral sensory neuropathy since 2006, so it is paid out of pocket. We use it as supportive care inside a driver-directed plan, never as the treatment. See what we actually provide on site.

Does infrared help if my neuropathy is diabetic?

Diabetic peripheral neuropathy is driven by metabolic and microvascular injury, so the work that changes the trajectory is metabolic. One 12-week sham-controlled trial in painful diabetic neuropathy reported symptom and quality of life benefit with no increase in nerve fiber density, which is a fair description of what to expect: infrared may make you more comfortable while the metabolic work does the structural job. It does not substitute for that work. See diabetic peripheral neuropathy treatment in St. Louis.

Will infrared help if my neuropathy comes from a B12 deficiency?

It will not correct the deficiency, and correcting the deficiency is the point. Heat and light do nothing about absorption, intake, or the medications that interfere with B12. Infrared can sit alongside that correction for comfort; it cannot replace it. See functional B12 deficiency and neuropathy.

What about gluten-related neuropathy?

Same answer, different mechanism. If an immune reaction to gluten is driving the nerve injury, the intervention that matters is dietary and immunologic, not thermal. Note also that people with non-diabetic drivers were not enrolled in the infrared trials at all, so there is no trial evidence either way for this group. See the gluten and neuropathy connection.

My nerve conduction study was normal but my feet still burn. Would infrared help?

A normal conduction study with ongoing burning points toward small fiber involvement, which standard nerve conduction testing often does not capture. The next step is a workup matched to that pattern rather than another modality, because a modality chosen before the driver is identified is a guess. See small fiber neuropathy symptoms and testing.

Sources

1. Wang JY, Huang ZQ, Deng HP, Zhao L, Deng HY, Liu JP, Shen XY, Cheng K. Low level light therapy/photobiomodulation for diabetic peripheral neuropathy: protocol of a systematic review and meta-analysis. BMJ Open. 2022;12(9):e059476. pmc.ncbi.nlm.nih.gov
2. Centers for Medicare & Medicaid Services. National Coverage Determination 270.6, Infrared Therapy Devices. Effective 24 October 2006; implemented 16 January 2007. Medicare Coverage Database. cms.gov
3. Centers for Medicare & Medicaid Services. Decision Memorandum for Infrared Therapy Devices (CAG-00291N). Medicare Coverage Database. 24 October 2006. cms.gov
4. Robinson CC, Klahr PDS, Stein C, Falavigna M, Sbruzzi G, Plentz RDM. Effects of monochromatic infrared phototherapy in patients with diabetic peripheral neuropathy: a systematic review and meta-analysis of randomized controlled trials. Brazilian Journal of Physical Therapy. 2017;21(4):233-243. pmc.ncbi.nlm.nih.gov
5. Lavery LA, Murdoch DP, Williams J, Lavery DC. Does anodyne light therapy improve peripheral neuropathy in diabetes? A double-blind, sham-controlled, randomized trial to evaluate monochromatic infrared photoenergy. Diabetes Care. 2008;31(2):316-321. pubmed.ncbi.nlm.nih.gov
6. Clifft JK, Kasser RJ, Newton TS, Bush AJ. The effect of monochromatic infrared energy on sensation in patients with diabetic peripheral neuropathy: a double-blind, placebo-controlled study. Diabetes Care. 2005;28(12):2896-2900. pubmed.ncbi.nlm.nih.gov
7. Rastogi A, Uppula P, Saikia U, Bhansali A. Effect of monochromatic infrared energy on quality of life and intraepidermal nerve fiber density in painful diabetic neuropathy: a randomized, sham control study. Neurology India. 2021;69(5):1331-1337. pubmed.ncbi.nlm.nih.gov
8. Nawfar SA, Yacob NB. Effects of monochromatic infrared energy therapy on diabetic feet with peripheral sensory neuropathy: a randomised controlled trial. Singapore Medical Journal. 2011;52(9):669-672. pubmed.ncbi.nlm.nih.gov
9. Korada HY, Arora E, Maiya GA, Rao S, Hande M, Shetty S, Gundmi S, Anche P, Amravadi S. Effectiveness of photobiomodulation therapy on neuropathic pain, nerve conduction and plantar pressure distribution in diabetic peripheral neuropathy: a systematic review. Current Diabetes Reviews. 2023;19(9):e290422204244. pubmed.ncbi.nlm.nih.gov
10. Fan X, Yan G, Cao J, Zhao Y, Wang Y, Wang X, Mi J. Effectiveness and safety of photobiomodulation therapy in diabetic peripheral neuropathy: protocol for a systematic review and meta-analysis. PLOS ONE. 2024;19(8):e0308537. pmc.ncbi.nlm.nih.gov
11. Pizzey FK, Smith EC, Ruediger SL, Keating SE, Askew CD, Coombes JS, Bailey TG. The effect of heat therapy on blood pressure and peripheral vascular function: a systematic review and meta-analysis. Experimental Physiology. 2021;106(6):1317-1334. pubmed.ncbi.nlm.nih.gov
12. Tesfaye S, Selvarajah D. Advances in the epidemiology, pathogenesis and management of diabetic peripheral neuropathy. Diabetes/Metabolism Research and Reviews. 2012;28 Suppl 1:8-14. pubmed.ncbi.nlm.nih.gov

VNG, or videonystagmography, measures a type of eye movement you cannot control, called nystagmus, in order to test how well your inner-ear balance system and the balance pathways in your brain are working.¹ It is a diagnostic test, not a treatment, and it does not measure peripheral nerve function at all.

In someone who already has neuropathy, it answers one narrow and useful question: is part of the unsteadiness coming from the vestibular system rather than from the nerves in the feet? That distinction changes what the balance plan should look like.

What the test records

A camera inside a pair of goggles records your eye movements while the examiner changes what you are looking at, where your head is, and the temperature inside your ear canal.

Brief nystagmus is normal as the eyes adjust when the head moves into certain positions. Nystagmus that appears at other times, or fails to appear when it should, may indicate a disorder of the balance system in the inner ear.¹

That is what makes it worth doing. Eye movement is involuntary, so the recording is an objective signal in a situation where the symptom itself — feeling unsteady — is notoriously hard to describe.

The three parts of the test

A VNG has three main components, and each probes a different part of the balance circuitry.¹

• Ocular testing. You follow moving lights and hold your gaze on steady lights without moving your head.
• Positional testing. Your head and body are moved into different positions while the goggles watch for nystagmus.
• Caloric testing. Each ear is tested on its own, first with cool water or air and then with warm water or air in the same ear.

What the caloric portion is looking for

The cool temperature should make the eyes move in a particular way, and the warm temperature should produce a different response.¹ Testing one ear at a time is what allows the two sides to be compared.

When the eyes do not move as expected during caloric testing, it may mean there is damage in the inner ear or in the part of the brain that controls balance.¹ Abnormal VNG results are also associated with conditions such as benign paroxysmal positional vertigo, Ménière disease, labyrinthitis and vestibular neuritis.¹

Why this matters when you have neuropathy

Standing upright depends on three inputs: sensation from the feet and legs, vision, and the vestibular system. Peripheral neuropathy degrades the first one. If the third one is also impaired, the loss compounds, and a person who could compensate for one problem cannot compensate for two.

Patients often describe both at once — numb feet and a swimming, off-balance feeling — and it is easy for everything to get attributed to the neuropathy. Testing separates them.

Balance can fail in more than one place at a time

Sorting this out is not academic. Vestibular findings direct one kind of rehabilitation, while sensory loss in the feet directs another, including footwear, lighting, home hazards and the protective habits that matter when the feet no longer report injury.

Getting the proportions right is how a fall risk gets addressed rather than described.

What VNG does not tell you

VNG does not identify your neuropathy driver. Peripheral neuropathy is a category rather than a diagnosis, and the work of finding out whether the cause is metabolic, nutritional, autoimmune, toxic or structural happens elsewhere in the evaluation.

It also does not treat anything. A normal VNG is useful information — it moves the balance problem back toward the feet — but neither a normal nor an abnormal result is a therapy.

How it fits into an evaluation at Regenerve

Electrodiagnostic testing (EMG/NCS) is performed on site and characterizes how the peripheral nerves are conducting. VNG is used when balance, dizziness or fall history suggests the vestibular system may also be involved.

The two are read together, alongside your symptom timeline, medications and metabolic and nutritional workup. Our page on VNG balance testing covers what to expect on the day of the test itself.

Bring the specifics with you: when the unsteadiness happens, whether it is worse in the dark, whether the room spins or you simply feel adrift, and whether you have fallen. Those details shape how the results are interpreted.

Start with the Nerve Damage Score

The Nerve Damage Score is five questions, and it is free. It is the starting point for identifying which driver is most likely damaging your nerves, which is the piece VNG cannot supply. We do not promise that nerve damage can be regenerated or reversed.

Regenerve, 4477 Woodson Rd #104, St. Louis, MO 63134. Call or text (314) 886-5902, or email info@regenerve.com. We are minutes from St. Louis Lambert International Airport and see patients from across the St. Louis region, Missouri and Illinois, including Edwardsville, Glen Carbon, Collinsville, Troy and Maryville.

Frequently asked questions

What does VNG balance testing measure?

It records involuntary eye movements, called nystagmus, with infrared goggles, and uses the timing and conditions of those movements to assess the inner-ear balance system and the balance pathways in the brain. It is a diagnostic test, not a treatment. See our VNG balance testing page.

Is VNG the same as nerve testing for neuropathy?

No. VNG evaluates vestibular function through eye movement, while electrodiagnostic testing (EMG/NCS) measures how peripheral nerves conduct. They answer different questions and are often ordered together when both feet and balance are involved. See the testing and care we provide on site.

Can VNG tell me why my feet are numb?

It cannot. Numbness in the feet is a peripheral nerve finding, and VNG does not measure peripheral nerves at all. What it can do is show whether some of your unsteadiness is coming from a second problem in the inner ear. See peripheral neuropathy of the feet symptoms.

Why would someone with diabetes be sent for balance testing?

Because unsteadiness in diabetes is rarely one thing. Reduced sensation in the feet, vision changes and vestibular problems can all contribute at once, and the plan differs depending on which is dominant. See diabetic peripheral neuropathy treatment in St. Louis.

What happens if my VNG is abnormal?

An abnormal result points to the vestibular system or the balance-related pathways in the brain, and it directs the balance side of your care. It does not identify the driver behind your neuropathy, so that mapping still has to happen separately. See the hidden drivers of peripheral neuropathy.

Sources

1. MedlinePlus, National Library of Medicine. Videonystagmography (VNG). MedlinePlus Medical Test. Last updated 28 June 2023. medlineplus.gov

Topical lidocaine and capsaicin 8% are the two topical options with the clearest evidence behind them for neuropathic foot pain, and which one fits depends on what is driving the neuropathy rather than on how the burning feels. An expert panel convened by the American Academy of Pain Medicine reported strong evidence and high consensus that capsaicin 8% is effective for diabetic peripheral neuropathy and for postherpetic neuralgia, and moderate evidence with high consensus that lidocaine is likely effective for diabetic peripheral neuropathy, idiopathic neuropathy and postsurgical neuropathy.¹

The counterweight matters just as much. A Cochrane review of topical lidocaine in adults with chronic neuropathic pain found only 12 studies covering 508 participants in total, all judged at high risk of bias, and concluded that there was no good-quality randomized evidence to support its use.² Topicals change the signal at the skin and nerve surface. They do not change what is damaging the nerve.

What to know before you try a topical

• Topicals modulate the signal, not the driver. The burning is an alarm, and the alarm keeps sounding while the underlying problem continues.
• The evidence is condition-specific. Support for lidocaine and for capsaicin 8% is attached to named diagnoses, not to “neuropathy” as a category.
• Peripheral neuropathy is a category, not a diagnosis. Metabolic, nutritional, autoimmune, toxic and structural drivers are often layered in the same patient.
• Testing changes decisions. On-site electrodiagnostic testing (EMG/NCS) helps establish which fibers are involved before a plan is built around a product.

What topical lidocaine does, and what it does not do

Lidocaine is a local anesthetic. Applied to the skin, it reduces the excitability of nerve endings under the area it covers, which can lower the intensity of burning or shooting pain in that patch of skin.

What it does not do is reach the cause. It does not improve flow through the small vessels that feed the nerve, correct a nutritional deficiency, or slow the metabolic chemistry that damaged the fiber in the first place.

Where the support is, and where it is not

The American Academy of Pain Medicine panel placed lidocaine’s strongest rating with postherpetic neuralgia, where it found strong evidence and high consensus that lidocaine is effective. For diabetic peripheral neuropathy, idiopathic neuropathy and postsurgical neuropathy the rating was moderate evidence with high consensus that lidocaine is likely effective.¹

Read the Cochrane finding alongside that rather than instead of it. Twelve small trials in 508 adults is a thin evidence base, and thin evidence is a reason to set expectations carefully, not on its own a reason to rule out a low-risk option.² Whether a prescription or over-the-counter topical belongs in your plan is a decision for your prescribing clinician.

Capsaicin 8% and when the diagnosis matches

Capsaicin works through a different pathway than lidocaine, and its labeled use is narrower. Qutenza (capsaicin 8% patch) is FDA-approved in adults only for neuropathic pain from postherpetic neuralgia and from diabetic peripheral neuropathy of the feet. Use for any other neuropathy driver is off-label, and it should be described that way before you agree to it.

The evidence rating tracks the label closely. The same expert panel found strong evidence and high consensus for capsaicin 8% in diabetic peripheral neuropathy and postherpetic neuralgia, and weaker ratings for other neuropathic pain conditions.¹

What “applied in clinic” means

The capsaicin 8% patch is applied at Regenerve by a clinician. It is not dispensed for home use, and it is not repeated more often than every three months.

That spacing is part of how the treatment is designed, and it is one more reason the diagnosis has to be settled before the patch is scheduled. Our page on the Qutenza capsaicin 8% patch describes what the visit itself involves.

Why the driver decides what belongs in the plan

Patients often arrive with a list of creams, patches and counterirritants collected online. The list is not the problem. The problem is that it is organized around the sensation instead of around the cause, so two people with identical burning end up on identical products for entirely different diseases.

We work the other way around, starting from which driver is doing the most damage right now.

• Metabolic pattern. When the distribution and history fit diabetic peripheral neuropathy of the feet, both lidocaine and capsaicin 8% sit inside their evidence-supported and, for capsaicin 8%, FDA-labeled territory.
• Nutritional pattern. When the history points to B12 deficiency or a gluten-related process, a topical may make the nights easier while the actual correction happens elsewhere.
• Chemotherapy-related pattern. Symptom tools may still have a role, but the priority is understanding whether large fiber, small fiber or mixed involvement is present.
• Autoimmune or structural pattern. Topicals alone are the weakest choice here, because inflammation and impaired perfusion keep the nerve irritable regardless of what is on the skin.

Testing that changes the decision

Electrodiagnostic testing (EMG/NCS) is performed on site at Regenerve. It characterizes large-fiber conduction, which helps separate a systemic driver from a focal compression and tells us whether the symptom picture and the wiring picture agree.

Where unsteadiness or dizziness is also part of the story, VNG is available. VNG is a diagnostic test of inner-ear balance function, not a treatment, and it is used to find out whether the balance problem sits in the vestibular system rather than in the feet.

What to bring to your visit

Your clinician needs more than “it burns.” Pattern, timing and history are what narrow the list.

• Where it is: toes, forefoot, midfoot or the whole foot, and whether both sides are equally affected.
• When it is worst: particularly whether it wakes you at night.
• What it feels like: burning, tingling, electric shocks, numbness, or pain from light touch such as a bedsheet.
• Your history: diabetes or prediabetes, chemotherapy, alcohol use, celiac or gluten sensitivity, bariatric or other gastrointestinal surgery, known B12 status, and any toxic exposures.
• What has already been tested: prior EMG/NCS results and whether small fiber involvement has been raised.

Start with the Nerve Damage Score

The Nerve Damage Score is five questions, and it is free. It is designed to identify which driver is most likely doing the damage in your case, so the conversation about topicals starts from a diagnosis instead of a product list. We do not promise that nerve damage can be regenerated or reversed.

Regenerve, 4477 Woodson Rd #104, St. Louis, MO 63134. Call or text (314) 886-5902, or email info@regenerve.com. We are minutes from St. Louis Lambert International Airport and see patients from across the St. Louis region, Missouri and Illinois, including Edwardsville, Glen Carbon, Collinsville, Troy and Maryville.

Frequently asked questions

Is topical lidocaine worth trying for burning feet at night?

It is reasonable to discuss when your pain pattern matches a condition where lidocaine has support, and it carries little systemic risk. Treat it as symptom modulation and pair it with an evaluation of what is driving the burning, because the relief stops when the patch does. See why feet burn at night.

Does topical lidocaine help diabetic peripheral neuropathy of the feet?

The American Academy of Pain Medicine panel rated lidocaine as likely effective for diabetic peripheral neuropathy on moderate evidence with high consensus. It does not address the metabolic and microvascular injury underneath, which is where the rest of the plan goes. See diabetic peripheral neuropathy treatment in St. Louis.

Is the capsaicin 8% patch an option if my neuropathy is not diabetic?

Qutenza is FDA-approved in adults only for postherpetic neuralgia and for diabetic peripheral neuropathy of the feet, so any other driver is an off-label use and has to be discussed as such. It is applied in clinic by a clinician and repeated no more often than every three months. See the hidden drivers of peripheral neuropathy.

Why do topicals help less when I have small fiber neuropathy?

Small fiber involvement produces burning, hot-coal sensations and altered temperature perception that can be widespread rather than confined to the patch of skin a topical covers. Standard nerve conduction studies may also look normal, which is why the workup has to match the symptom pattern. See small fiber neuropathy symptoms and testing.

Should I get nerve testing before trying a topical?

Not necessarily before, but testing changes what comes after. Electrodiagnostic testing clarifies which fibers are affected, which narrows the list of likely drivers and tells us whether a topical is a bridge or a distraction. See treatment options for peripheral neuropathy in the feet.

Sources

1. American Academy of Pain Medicine. Topical analgesics for neuropathic pain: an evidence-informed guide for the practicing clinician. Pain Medicine. 2026. AAPM clinical guideline summary
2. Derry S, Wiffen PJ, Moore RA, Quinlan J. Topical lidocaine for neuropathic pain in adults. Cochrane Database of Systematic Reviews. 2014. PMID 25058164

A skin punch biopsy counts the nerve fibers inside the epidermis and reports that count as intraepidermal nerve fiber density, or IENFD. A low count is objective evidence that the small sensory fibers are damaged — the fibers that carry pain and temperature, and the ones that produce burning feet while a standard nerve conduction study reads normal.

What the biopsy does not tell you is why those fibers are failing. That is the part that decides treatment, and it comes from the rest of the workup rather than from the number.

The test is used well beyond classic neuropathy presentations. Approximately 40% to 60% of patients carrying a diagnosis of fibromyalgia have evidence of small fiber neuropathy on skin punch biopsy.¹

Regenerve performs the punch skin biopsy on site, so the sample is taken during a clinic visit rather than referred out.

How the test is done

A 3 mm punch is inserted into the biopsy site to take a small cylinder of skin, typically from the lower leg.¹ The sample goes to a laboratory that stains the nerve fibers and counts how many cross into the epidermis per millimeter of tissue. That count is compared against reference values matched to site, age and sex.

It is a minor office procedure rather than a surgical one, and it samples the fibers directly instead of inferring their state from an electrical signal.

Why standard nerve testing can come back normal

Nerve conduction studies measure large myelinated fibers. Small fibers are unmyelinated or thinly myelinated and do not contribute to that signal, so they can be substantially damaged while the study reads normal.

Peripheral neuropathy is primarily diagnosed clinically, through history and neurological assessment of small fiber sensation with temperature or pinprick, large fiber sensation with vibration, and ulceration risk with 10 g monofilament pressure testing.² Nerve conduction studies and intraepidermal nerve fiber density testing are indicated where there are atypical clinical features, such as rapid symptom onset, severe neuromotor impairment or asymmetrically abnormal sensation.²

Regenerve performs electrodiagnostic testing (EMG/NCS) on site, and reads it against the clinical picture rather than treating it as a verdict. A normal study in someone with burning feet is a reason to look at the small fibers, not a reason to stop looking.

A normal biopsy does not close the case

Using current normal values, epidermal nerve fiber density is abnormally decreased in only about two-thirds of patients suspected of having small fiber neuropathy.³ That means roughly one in three patients with a convincing clinical picture will have a biopsy that reads normal.

Reference ranges, sampling site and laboratory methodology all shift where the line between normal and abnormal falls. A single number in isolation is not a diagnosis, and a normal result in someone whose symptoms fit is a reason to widen the search rather than to stop.

What each result changes

• Low IENFD. Small fiber damage is confirmed. The question moves entirely to which driver is producing it.
• Normal IENFD with fitting symptoms. The clinical picture still stands. Alternative or overlapping mechanisms get evaluated, and the biopsy result is recorded rather than used to dismiss the complaint.
• Normal IENFD with an atypical picture. The differential widens beyond small fiber involvement.

The biopsy tells you the fibers are damaged, not what damaged them

Neuropathy is a category, not a diagnosis. Small fiber damage can arise from metabolic, nutritional, autoimmune, toxic or structural drivers, and it is common for more than one to be active at the same time.

That is where the evaluation actually lives — establishing which mechanism is doing the damage, then directing treatment at it. Our discussion of the contributors that most often get missed is in the hidden drivers of peripheral neuropathy.

Driver categories we work through

• Metabolic. Glucose handling, insulin resistance and glycation-related injury.
• Nutritional. Absorption problems and nutrient status, including after abdominal or bariatric surgery.
• Autoimmune. Systemic inflammatory and immune-mediated processes.
• Toxic. Medications, alcohol, chemotherapy exposure and environmental agents.
• Structural. Compression and mechanical contributors that can sit on top of any of the above.

What we do with the result

At Regenerve the biopsy result feeds into a plan built around the identified driver. That plan can include class 4 photobiomodulation, class 3B cold laser, whole-body infrared, and metabolic and nutritional care.

Orthobiologic injections (PRP and BMAC) are offered. Where balance complaints are part of the picture, VNG (videonystagmography) may be used as a diagnostic test of inner-ear balance function; it is not a treatment. Nothing offered here reverses or regenerates nerve damage, and no outcome is promised.

Questions worth asking before a biopsy

• What in my history makes small fiber involvement the leading suspicion?
• Which site will be sampled, and which laboratory and reference values will be used?
• What will change in my evaluation if the result is low?
• What is the next step if the result comes back normal but my symptoms do not?

Being evaluated in St. Louis

Regenerve is at 4477 Woodson Rd #104, St. Louis, MO 63134, minutes from St. Louis Lambert International Airport, and is led by Dr. Gurpreet Singh Padda, MD, MBA, MHP. The practice serves the St. Louis region, Missouri and Illinois.

Call or text (314) 886-5902, or email info@regenerve.com. Office hours are Monday through Thursday 9:00 to 16:00 and Friday 9:00 to 13:30.

If a nerve test came back normal and your feet still burn, the Nerve Damage Score is a free five-question assessment that produces a large-print report you can bring to any physician.

Frequently asked questions

What does a skin biopsy for small fiber neuropathy involve?

A 3 mm punch takes a small cylinder of skin, usually from the lower leg, and a laboratory counts how many nerve fibers cross into the epidermis per millimeter. It is an office procedure, not surgery. See the testing and services we provide.

How is it different from an EMG and nerve conduction study?

Nerve conduction studies measure large myelinated fibers; the biopsy counts the small fibers directly. That is why burning feet can coexist with a nerve conduction study that reads normal. See burning feet and nerve pain.

Can I have small fiber neuropathy if my biopsy is normal?

Yes. Using current normal values, epidermal nerve fiber density is abnormally decreased in only about two-thirds of patients suspected of having small fiber neuropathy, so a normal result does not exclude the diagnosis. See how to choose a neuropathy specialist.

If my biopsy is abnormal, what happens next?

The work shifts to identifying which driver is damaging the fibers — metabolic, nutritional, autoimmune, toxic or structural — because that is what determines treatment rather than the density number itself. See how sugar damages nerves.

Is this test only relevant to diabetes?

No. Small fiber damage shows up across nutritional, autoimmune and toxic drivers as well, and roughly 40% to 60% of patients carrying a fibromyalgia diagnosis have evidence of it on skin punch biopsy. See functional B12 deficiency and neuropathy.

Sources

1. Kelley MA, Hackshaw KV. Intraepidermal Nerve Fiber Density as Measured by Skin Punch Biopsy as a Marker for Small Fiber Neuropathy: Application in Patients with Fibromyalgia. Diagnostics (Basel). 2021;11(3):536. PMID 33802768
2. Bodman MA, Dreyer MA, Varacallo MA. Diabetic Peripheral Neuropathy. StatPearls. StatPearls Publishing. 2024. NCBI Bookshelf NBK442009
3. Levine TD, Saperstein DS. Diagnosing Small Fiber Neuropathy Through the Use of Skin Biopsy. Practical Neurology. October 2009. practicalneurology.com

The dividing line is what your legs are asking you to do. Restless legs syndrome produces an urge to move that comes on at rest, worsens in the evening and eases when you actually move. Peripheral neuropathy produces abnormal sensation — burning, numbness, tingling — that moving does not reliably relieve, and that usually starts in the feet and works upward.

Both keep people awake, which is why they get confused. Between 5% and 15% of the population may have restless legs syndrome.¹ Peripheral neuropathy presents with varying degrees of numbness, tingling, aching, burning sensation, weakness of the limbs, hyperalgesia, allodynia and pain.² The overlap in how they feel at midnight is real; the underlying physiology is not the same.

Why sorting them out is harder than it looks

The best evidence on this is a case-control study of 245 patients with peripheral neuropathy and 245 age- and sex-matched controls, screened for restless legs syndrome with a standardized questionnaire based on international diagnostic criteria.³

On screening, 65 of the neuropathy patients (26.5%) came back positive for restless legs syndrome, versus 25 of the controls (10.2%). That looks like a large excess. But when a movement disorders specialist, blinded to neuropathy status, examined the screen-positive patients, the diagnosis was confirmed in only 46% of the neuropathy group compared with 80% of the controls.³

After that confirmation step, overall restless legs prevalence did not differ between the neuropathy patients and the controls: 12.2% versus 8.2%.³ The commonest reasons for a false-positive screen were cramps and paresthesia without true diurnal variation or worsening at rest.³

That is the practical lesson for anyone trying to name their own symptoms: neuropathy sensations frequently answer “yes” to restless legs screening questions without meeting the actual criteria. Timing and rest-versus-movement are what separate them, and a questionnaire on its own gets it wrong more often than not in this group.

Where a real association was found

In the same study, restless legs syndrome was found in 14 of 72 patients with hereditary neuropathy (19.4%), a higher prevalence than in controls and than in acquired neuropathy (9.2%).³ Patients with neuropathy who did have restless legs more often had a family history of it and were younger, at an average of 49.9 years versus 61.4.³

The two patterns, side by side

What restless legs syndrome looks like

• An urge to move the legs, usually with uncomfortable sensations.
• Triggered or worsened by rest, especially sitting or lying down.
• Worse in the evening and at night than during the day.
• Partly or fully relieved by movement, for as long as the movement continues.

What peripheral neuropathy looks like

• Burning, numbness, tingling or electric sensations rather than an urge to move.
• Usually starts in the toes and feet and progresses upward, symmetrically.
• Often worse at night, but walking does not reliably switch it off.
• May come with loss of protective sensation, balance change or altered gait.

The feet-first, symmetrical progression is the most useful single discriminator. An urge that rest brings on and walking relieves is the other.

Neuropathy is a category, so the next question is which driver

Once the pattern points to nerve injury rather than a movement disorder, the label “neuropathy” is only the halfway point. The driver can be metabolic, nutritional, autoimmune, toxic or structural, and each one changes what is worth doing.

Peripheral neuropathy is primarily diagnosed clinically, through history and neurological assessment of small fiber sensation with temperature or pinprick, large fiber sensation with vibration, and ulceration risk with 10 g monofilament pressure testing.² Nerve conduction studies and intraepidermal nerve fiber density testing are indicated where there are atypical clinical features, such as rapid symptom onset, severe neuromotor impairment or asymmetrically abnormal sensation.²

Testing we perform on site

Regenerve performs electrodiagnostic testing (EMG/NCS) in the office, which is what large-fiber involvement is assessed with. Where balance complaints or dizziness are part of the picture, VNG (videonystagmography) may be used as a diagnostic test of inner-ear balance function. VNG identifies where a balance problem is coming from; it is not a treatment. Details are on our VNG balance testing page.

When both are present

The two can coexist, and a family history of restless legs plus a younger age at onset makes that more likely in someone who already has neuropathy.³ Finding one does not close the file on the other.

Where both are in play, the plan has to address the nerve driver and the movement-discomfort pattern as separate problems, because treating only one leaves the other running at night.

What we do at Regenerve

Our approach is driver-directed rather than symptom-directed. That means identifying what is injuring the nerve before selecting anything, then matching the plan to it.

• Electrodiagnostic testing (EMG/NCS) performed on site.
• Class 4 photobiomodulation and class 3B cold laser.
• Whole-body infrared.
• Metabolic and nutritional care directed by the identified driver.
• Orthobiologic injections (PRP and BMAC).
• Qutenza (capsaicin 8% patch), FDA-approved in adults for neuropathic pain from postherpetic neuralgia and from diabetic peripheral neuropathy of the feet, applied in clinic by a clinician and repeated no more often than every three months. Use for any other driver is off-label.
• VNG balance testing, which is diagnostic only.

Surgery is not part of the treatment plan for peripheral neuropathy itself, and nothing here is offered as a way to reverse or regenerate nerve damage.

Being evaluated in St. Louis

Regenerve is at 4477 Woodson Rd #104, St. Louis, MO 63134, minutes from St. Louis Lambert International Airport, and is led by Dr. Gurpreet Singh Padda, MD, MBA, MHP. The practice serves the St. Louis region, Missouri and Illinois.

Call or text (314) 886-5902, or email info@regenerve.com. Office hours are Monday through Thursday 9:00 to 16:00 and Friday 9:00 to 13:30.

If your legs keep you awake and you are not sure which of these you have, the Nerve Damage Score is a free five-question assessment that produces a large-print report you can bring to any physician.

Frequently asked questions

Can restless legs syndrome feel like peripheral neuropathy?

Yes, and the confusion runs in both directions. In one case-control study, 26.5% of peripheral neuropathy patients screened positive for restless legs but the diagnosis was confirmed in only 46% of them, with cramps and paresthesia the commonest false-positive causes. See burning feet and nerve pain.

How do clinicians tell them apart?

By timing and by what movement does. An urge to move that is triggered by rest, peaks in the evening and eases while walking points to restless legs; burning or numbness that starts in the toes and progresses upward symmetrically points to nerve injury. See how to choose a neuropathy specialist.

Is burning at night more likely to be neuropathy?

Burning is a sensory symptom rather than an urge to move, so it fits the neuropathy pattern more closely, particularly small fiber involvement. That does not exclude restless legs, since the two can coexist. See small fiber neuropathy symptoms and testing.

Does having neuropathy raise my risk of restless legs syndrome?

In hereditary neuropathy it did — 19.4% versus 9.2% in acquired neuropathy — but after diagnostic confirmation, overall prevalence in neuropathy patients (12.2%) did not differ significantly from matched controls (8.2%). See the hidden drivers of peripheral neuropathy.

Will treating my diabetes help either problem?

Addressing a metabolic driver targets the nerve injury, not the movement-discomfort mechanism, so an urge-to-move pattern still needs to be assessed on its own. Both should be named separately before a plan is built. See diabetic peripheral neuropathy treatment in St. Louis.

Sources

1. Mansur A, Castillo PR, Rocha Cabrero F, Bokhari SRA. Restless Legs Syndrome. StatPearls. StatPearls Publishing. Updated February 27, 2023. NCBI Bookshelf NBK430878
2. Bodman MA, Dreyer MA, Varacallo MA. Diabetic Peripheral Neuropathy. StatPearls. StatPearls Publishing. 2024. NCBI Bookshelf NBK442009
3. Hattan E, Chalk C, Postuma RB. Is there a higher risk of restless legs syndrome in peripheral neuropathy? Neurology. 2009;72(11):955–960. PMID 19038854

The patch itself is on for 60 minutes if you are being treated for postherpetic neuralgia, or 30 minutes if it is being applied to the feet for diabetic peripheral neuropathy.¹ Around that, expect skin marking and preparation, an optional topical anesthetic beforehand, and blood pressure monitoring during and after the application. The whole visit runs considerably longer than the patch time.

Qutenza is applied by a clinician in the office. The label states plainly that it is not to be dispensed to patients for self-administration or handling, and that only physicians or health care professionals are to administer it.¹

What Qutenza is approved for, and what we confirm first

Qutenza is indicated in adults for the treatment of neuropathic pain associated with postherpetic neuralgia and for neuropathic pain associated with diabetic peripheral neuropathy of the feet.¹ It is a TRPV1 channel agonist, not a general-purpose neuropathy patch.

Use for any other neuropathy driver — chemotherapy-related, nutritional, autoimmune, toxic or idiopathic — is off-label. If it is proposed for one of those, that should be stated to you as an off-label decision before anything is applied.

Why the driver is established before the patch is considered

Peripheral neuropathy is primarily diagnosed clinically, through history and neurological assessment of small fiber sensation, large fiber sensation and ulceration risk.² Neuropathy is a category rather than a diagnosis, so the first part of the visit is establishing which driver is producing your pain and whether the distribution matches an approved indication.

Regenerve performs electrodiagnostic testing (EMG/NCS) on site. Nerve conduction studies are indicated where there are atypical clinical features such as rapid symptom onset, severe neuromotor impairment or asymmetrically abnormal sensation.² If your history includes shingles, the relevant background is on our page about postherpetic neuralgia and shingles nerve pain.

Before the patch: marking, preparation and the optional anesthetic

The treatment area — the painful area, including regions of hypersensitivity and allodynia — is identified by a physician and marked on the skin.¹ Hair may be clipped, not shaved, to help the patch adhere, and the area is washed with mild soap and water and dried thoroughly.¹

Pretreatment with a topical anesthetic is optional under the label. Where it is used, it is applied to the whole treatment area plus 1 to 2 cm around it and kept in place until the skin is anesthetized, then wiped off and the area washed again before the patch goes on.¹ There is no fixed numbing time; it runs until the skin is ready.

What to bring

• Your current medication list, including pain medicines and supplements.
• Any history of reaction to topical agents.
• Your blood pressure history, particularly if it is unstable or poorly controlled.

During the application

The patch is placed on the marked area and smoothed onto the skin. For diabetic peripheral neuropathy it can be wrapped around the dorsal, lateral and plantar surfaces of each foot to cover the treatment area completely.¹ A dressing such as rolled gauze may be used to maintain contact. You are asked not to touch the patch or the treated area.

The recommended dose is up to four topical systems: 60 minutes for postherpetic neuralgia, 30 minutes on the feet for diabetic peripheral neuropathy.¹

What it feels like

Expect burning and warmth in the treated field. The label is direct about this: even after a local anesthetic is used, patients may experience substantial procedural pain and burning during application and after removal, and clinicians are told to be prepared to treat that acute pain with local cooling or appropriate analgesic medication.¹

Tell the clinician immediately if you feel dizzy or otherwise unwell during the application rather than waiting for the timer to finish.

Blood pressure monitoring

In clinical trials, transient increases in blood pressure occurred during or shortly after exposure to Qutenza. The changes averaged less than 10 mm Hg, though some patients had larger increases, and the changes lasted approximately two hours after removal.¹ Blood pressure is monitored periodically during and following the procedure for that reason.

Application-site reactions

Across all controlled clinical trials, the most common adverse reactions occurring in at least 5% of treated patients and more often than in controls were application site erythema, application site pain and application site pruritus.¹ In the postherpetic neuralgia trials, application site erythema occurred in 63% of patients treated with Qutenza compared with 54% of controls, and application site pain in 42% compared with 21%.¹

After the patch comes off

The patch is removed slowly by rolling it inward, and cleansing gel is applied to the treated area and wiped off with dry gauze. Patients are advised that the treated area may be sensitive for a few days to heat — hot showers or baths, direct sunlight and vigorous exercise.¹

Contact the clinic if you develop anything beyond expected local sensitivity. The label carries specific warnings about severe application site burns and about reductions in sensory function, which are generally minor and temporary but are assessed before each subsequent application.¹

How often it can be repeated

Treatment may be repeated every three months, or as warranted by the return of pain, and not more frequently than every three months.¹ That is a ceiling on frequency, not a promise about how long relief lasts, and how long any individual patient goes between applications varies.

Where the patch sits in a larger plan

Qutenza acts locally on the pain signal in the treated skin. It does not address whatever is injuring the nerve, which is why the application is scheduled alongside driver-directed work rather than instead of it.

That work at Regenerve can include class 4 photobiomodulation, class 3B cold laser, whole-body infrared, and metabolic and nutritional care, chosen against the driver identified during evaluation. Orthobiologic injections (PRP and BMAC) are offered. Where balance or dizziness is part of the picture, VNG (videonystagmography) may be used as a diagnostic test of inner-ear balance function; it is not a treatment.

Patch specifications

Each Qutenza topical system is 14 cm x 20 cm (280 cm²) and contains 8% capsaicin, 640 mcg per cm², for a total of 179 mg of capsaicin per system — 8% in the adhesive, 80 mg per gram of adhesive.¹ It can be cut before the release liner is removed to match the size and shape of the treatment area.¹

Being evaluated in St. Louis

Regenerve is at 4477 Woodson Rd #104, St. Louis, MO 63134, minutes from St. Louis Lambert International Airport, and is led by Dr. Gurpreet Singh Padda, MD, MBA, MHP. The practice serves the St. Louis region, Missouri and Illinois.

Call or text (314) 886-5902, or email info@regenerve.com. Office hours are Monday through Thursday 9:00 to 16:00 and Friday 9:00 to 13:30.

Before scheduling anything, the Nerve Damage Score is a free five-question assessment that helps identify which driver is behind your symptoms and whether an approved indication is even in play.

Frequently asked questions

How long does the Qutenza patch stay on?

Sixty minutes for postherpetic neuralgia, and 30 minutes when applied to the feet for diabetic peripheral neuropathy, using up to four topical systems. The visit itself runs longer because of marking, optional anesthetic time, removal, cleansing and monitoring. See our Qutenza capsaicin 8% patch page.

How often can Qutenza be repeated?

Every three months, or as warranted by the return of pain, and not more frequently than every three months. Whether a repeat application is appropriate depends on your response and on whether your diagnosis still fits the approved indication. See diabetic peripheral neuropathy treatment in St. Louis.

What side effects are common?

Application site erythema, application site pain and application site pruritus are the most common reactions across controlled trials, and transient blood pressure increases averaging less than 10 mm Hg were seen during and shortly after treatment. That is why blood pressure is checked during the visit. See our neuropathy treatment FAQ.

Is Qutenza used for small fiber or idiopathic neuropathy?

Not within the approved indication. Qutenza is labeled for adults with neuropathic pain from postherpetic neuralgia and from diabetic peripheral neuropathy of the feet; any other driver is an off-label use and should be described that way. See small fiber neuropathy symptoms and testing.

Can I get the patch to use at home?

No. The label states that Qutenza is not to be dispensed to patients for self-administration or handling, and that only physicians or health care professionals administer it. Unintended capsaicin exposure can cause severe irritation of the eyes, mucous membranes, airway and skin. See the hidden drivers of peripheral neuropathy.

Sources

1. Averitas Pharma, Inc. QUTENZA (capsaicin) topical system — full prescribing information. Updated July 2026. DailyMed
2. Bodman MA, Dreyer MA, Varacallo MA. Diabetic Peripheral Neuropathy. StatPearls. StatPearls Publishing. 2024. NCBI Bookshelf NBK442009

Ask the questions that force the visit to name a cause. The three that matter most are “What pattern do my symptoms follow?”, “What is this evaluation ruling in and ruling out?”, and “What would each test change about my plan?” Neuropathy is a category, not a diagnosis, so an evaluation that ends at the word “neuropathy” has not finished its job.

Peripheral neuropathy presents with varying degrees of numbness, tingling, aching, burning sensation, weakness of the limbs, hyperalgesia, allodynia and pain.¹ That range is exactly why the symptom label alone cannot direct treatment, and why the questions below are organized around finding the driver instead.

It is worth asking, because careful evaluation identifies an underlying cause in roughly 50 to 75 percent of patients presenting with peripheral neuropathy.² The rest of this checklist is what “careful” looks like from the patient’s side of the table.

Start with the pattern, not the label

Where symptoms started, how they spread, and whether they are symmetrical are the first pieces of evidence a clinician works from. Your job is to describe that pattern precisely rather than summarize it as “my feet hurt.”

Questions that establish the pattern

• Where did this start, and in what order did it spread?
• Is it burning, numbness, weakness, or a combination?
• Are both sides affected equally, or is one side worse?
• What makes it worse and what makes it better across a normal day?
• Do I have balance changes, falls, or a change in how I walk?

A symmetrical, feet-first pattern that creeps upward points in a different direction than a sudden, one-sided, or rapidly progressive one. Say which of those describes you, and say it early in the visit.

Questions that make the evaluation commit

• What category are you most concerned about today?
• What finding would change your mind about that?
• What is this evaluation trying to rule in, and what is it trying to rule out?
• If this is small fiber involvement, how would you confirm it?

If you have diabetes, ask about classification and testing purpose

Diabetes being present does not settle the question. It raises a second one: is diabetes the whole driver, or one of several stacked on top of each other?

Peripheral neuropathy is primarily diagnosed clinically, through history and neurological assessment — small fiber sensation with temperature or pinprick, large fiber sensation with vibration, and ulceration risk with 10 g monofilament pressure testing.¹ Nerve conduction studies and intraepidermal nerve fiber density testing are indicated for patients with atypical clinical features, such as rapid symptom onset, severe neuromotor impairment, or asymmetrically abnormal sensation.¹

Questions about testing purpose

• Does anything about my presentation count as atypical?
• When would electrodiagnostic testing change what we do, rather than just confirm what we already suspect?
• If my nerve study is normal but my symptoms persist, what does that mean for the next step?
• How do my glucose history, A1c trend and kidney function change your concerns?

Regenerve performs electrodiagnostic testing (EMG/NCS) on site, which means the result is read against your history in the same building rather than mailed back weeks later as a number without a plan.

Do not stop at diabetes: ask about the other drivers

Nutritional, autoimmune, toxic and structural drivers can sit alongside a metabolic one, and they frequently do. If you have ever been told “nothing else explains it,” the useful follow-up is to ask what specifically was checked.

Hidden-driver questions

• Besides diabetes, what drivers are you actively considering today?
• Could nutrient absorption be contributing, and how would you test that?
• Could a medication, alcohol history, or an occupational exposure be involved?
• Did this begin after chemotherapy, surgery, or a shingles episode?
• If serum B12 is reported as normal, does that fully exclude a B12-related driver?

Our longer discussion of the contributors that get missed is in the hidden drivers of peripheral neuropathy, and it is a reasonable list to bring with you to any evaluation, here or elsewhere.

Bring your history in writing

The highest-yield questions come out of your own timeline. A clinician can map mechanism far faster when the specifics are on paper instead of being reconstructed from memory in a fifteen-minute visit.

What to write down before you go

• The month and year symptoms began, and anything that happened around that time.
• Every prescription, over-the-counter medicine and supplement, with doses.
• Prior surgeries, particularly abdominal or bariatric procedures.
• Alcohol history, stated honestly, because it changes the differential.
• Any prior nerve testing, lab work, or imaging, with the actual reports if you have them.

Ask what each treatment is aimed at

Once a driver is named, the questions shift from diagnosis to mechanism. The single most clarifying question about any proposed treatment is what it is intended to change — the symptom, or the process producing the symptom.

Treatment questions worth asking

• What is the dominant driver in my case, and what does that imply for treatment?
• What is each proposed therapy targeting, and how will we know whether it worked?
• Which parts of this plan address the ongoing injury rather than the pain signal?
• How will the plan change if the driver map changes?

Regenerve offers class 4 photobiomodulation, class 3B cold laser, whole-body infrared, and metabolic and nutritional care. Orthobiologic injections (PRP and BMAC) are also offered, which is how they should be described to you before you agree to anything.

If shingles is in your history, ask about Qutenza specifically

Qutenza (capsaicin 8% patch) is FDA-approved in adults for neuropathic pain associated with postherpetic neuralgia and for neuropathic pain associated with diabetic peripheral neuropathy of the feet.³ Use for any other neuropathy driver is off-label, and a clinician proposing it for another indication should say so plainly.

Questions about the patch

• Does my diagnosis fall inside the approved indication, or would this be off-label?
• How long is the application, and how long is the visit?
• How often can it be repeated?
• What monitoring happens during and after the application?

It is applied in clinic by a clinician, never dispensed for home use, and repeated no more often than every three months.³

Questions that test the quality of the evaluation itself

The last set is about the clinic rather than your nerves. A good evaluation should be able to answer these without hesitating.

• How do you document which driver you believe is dominant, and what evidence supports it?
• What testing do you perform on site, and what gets sent out?
• When is the next touchpoint, and what should I bring to it?
• What would make you tell me this is not the right clinic for my problem?

Being evaluated in St. Louis

Regenerve is at 4477 Woodson Rd #104, St. Louis, MO 63134, minutes from St. Louis Lambert International Airport, and is led by Dr. Gurpreet Singh Padda, MD, MBA, MHP. The practice serves the St. Louis region, Missouri and Illinois.

Call or text (314) 886-5902, or email info@regenerve.com. Office hours are Monday through Thursday 9:00 to 16:00 and Friday 9:00 to 13:30.

If you want your answers organized before the visit, the Nerve Damage Score is a free five-question assessment that produces a large-print report you can hand to any physician.

Frequently asked questions

What should I ask if my main symptom is numbness rather than pain?

Ask which fiber types the numbness pattern implicates and what test would confirm it, then ask what protective-sensation loss means for foot care in the meantime. Numbness without pain still needs a driver named. See small fiber neuropathy symptoms and testing.

How do I prepare if my feet burn at night?

Write down when the burning starts, whether it is symmetrical, and what changes it, then ask which mechanism the clinician thinks is producing it. Bring that description rather than a single-word summary. See burning feet and nerve pain.

Is a nerve conduction study always necessary?

No. Peripheral neuropathy is primarily a clinical diagnosis, and nerve conduction studies are indicated for atypical features such as rapid onset, severe neuromotor impairment, or asymmetric sensory findings. Ask what the result would change before agreeing to it. See how to choose a neuropathy specialist.

What should I ask if I think a B12 problem was missed?

Ask how functional B12 status is assessed when the serum level reads normal, and what would be measured alongside it. Then ask what treatment decision that testing would drive. See functional B12 deficiency and neuropathy.

What if gluten or celiac disease is a possibility for me?

Ask whether a gluten-related driver is on your differential, what testing supports or excludes it, and what happens if celiac testing is negative but symptoms fit. See the gluten and neuropathy connection.

Sources

1. Bodman MA, Dreyer MA, Varacallo MA. Diabetic Peripheral Neuropathy. StatPearls. StatPearls Publishing. 2024. NCBI Bookshelf NBK442009
2. Peripheral Neuropathy: Asking the Right Questions. Practical Neurology. March–April 2009. practicalneurology.com
3. Averitas Pharma, Inc. QUTENZA (capsaicin) topical system — full prescribing information. Updated July 2026. DailyMed

Two published trials have tested laser photobiomodulation in people who already have peripheral neuropathy, and both were run in neuropathy caused by chemotherapy. One compared a very low-power laser against a sham device and found the laser group’s response rate holding at twelve weeks while the control group’s fell.¹ The other used a class 4 laser, reported improvement in nerve score and walking distance, and had no control group at all.² Neither reports nerve regeneration, reversal, or a cure, and neither enrolled patients whose neuropathy comes from diabetes or metabolic disease.

That is a thin evidence base, and the honest thing to do with a thin evidence base is not to shrink from it but to read it carefully: what each trial measured, who it let in, who it kept out, and what its design was never built to answer. That is what the rest of this page does.

The short version

• Two trials, two very different lasers. The only sham-controlled trial used a class 2M laser rated in milliwatts. The only trial that used a class 4 laser had no control group.
• Dose is the variable, not the word “laser”. Wavelength, power density, energy density and treated area differ enormously between the two trials, and light therapy has a documented biphasic dose response.³
• Order of events matters. In the sham-controlled trial the control arm responded slightly more often at six weeks. The arms separated only at twelve weeks, which raises a question about how long a course needs to be.¹
• Both trials studied cancer survivors. Neither enrolled diabetic, nutritional, autoimmune or idiopathic neuropathy.
• The registered diabetic neuropathy laser trials screened out the harder patients — peripheral vascular disease, open wounds on the treatment area, recent diabetic ketoacidosis, and, in one protocol, anyone who had taken gabapentin, pregabalin, tramadol or an opioid in the previous month.^4,5
• Coverage is a payer decision, not a clinical finding. The 2006 Medicare determination that gets quoted here is about infrared diode pads, not about laser photobiomodulation.⁶
• Map the driver first. Which mechanism is active decides whether light-based therapy belongs in the plan at all.

What the question actually means

When people ask whether class 4 laser helps neuropathy, they usually mean whether laser light improves neuropathy symptoms in humans. The evidence base is real, but it is small, and it does not travel evenly across neuropathy types.

Neuropathy is a category, not a diagnosis

The same burning-feet complaint can come from metabolic injury, a vitamin deficiency, a toxic exposure, chemotherapy, an autoimmune process, or a structural cause. Those are different diseases that happen to share a symptom.

A trial run in one of those populations says very little about the others. That is not a criticism of the trials. It is a statement about what a trial in a defined population can and cannot be extended to cover.

Laser class describes hazard, not dose

Laser safety classes run from 1 up to 4 and describe how hazardous a beam is to the eye and skin. They are a regulatory hazard rating. They do not tell you the wavelength, the power density at the tissue, the energy delivered, or the area treated — and those are the things that determine what happens biologically.

This matters more here than it usually does, because the two published trials sit at opposite ends of that scale, and the one with a control arm is the one at the bottom.

Dose is the variable that separates these trials

Both trials are described as photobiomodulation. In terms of the light actually delivered, they have almost nothing in common.

The parameters that define a photobiomodulation dose

A photobiomodulation dose is defined by wavelength, power, power density at the tissue surface, energy density (fluence), the size of the treated area, whether the beam is continuous or pulsed, how long each session lasts, and how many sessions are given over what period. Change any one of those and you have changed the treatment.

The sham-controlled trial used a class 2M continuous-wave diode laser delivering 8 milliwatts through a 3.2 millimeter aperture, applied point by point — sixteen points in the interdigital spaces of the hands and feet, plus ten points over the cutaneous landmarks for the C6–T1 and L5–S1 nerve roots on both sides. The dose was prescribed as 1 joule per point, escalating to 2 joules per point in later sessions as tolerated, twice a week for six weeks.¹

The class 4 trial used a device combining two diodes at 905 nanometers and 808 nanometers, one pulsed and one continuous, with peak powers of 25 watts and 1.1 watts, a power density of 0.168 watts per square centimeter, and a beam spot of 150 square centimeters covering the plantar surfaces of the hands and feet bilaterally. The dose was prescribed as an energy density — 6 or 8 joules per square centimeter — twice weekly for three weeks.²

Notice that the two doses are not even reported in the same units. One is joules per point at twenty-six discrete points; the other is joules per square centimeter across a large field. There is no clean conversion between them, which means the two trials cannot be pooled, compared, or averaged in any meaningful way.

The biphasic dose response

This is not a bookkeeping problem. It is the central reason results in this literature diverge.

A 2009 review in the journal Dose-Response, from the Wellman Center for Photomedicine at Massachusetts General Hospital, described a biphasic dose response that has been observed repeatedly in low-level light therapy: low levels of light stimulate and repair tissue more effectively than higher levels do, a pattern the authors describe using the Arndt-Schulz curve.³ More is not better, and past a point more is worse.

The same review makes the point directly relevant to this page: the difficulty of choosing rationally among a large number of illumination parameters — wavelength, fluence, power density, pulse structure and treatment timing — has produced a body of literature containing both negative and positive studies.³ A negative photobiomodulation trial can mean the therapy does not work, or it can mean that particular dose did not work, and from outside the trial those two possibilities look identical.

So when a reader encounters mixed results in light therapy, the appropriate response is not to conclude the field is unserious. It is to ask what dose was tested, in whom, and for how long.

The sham-controlled trial: 44 cancer survivors, 2022

This is the only randomized, sham-controlled trial of photobiomodulation in established neuropathy discussed here, and it deserves to be read closely rather than quoted selectively.

Who was studied

Teng and colleagues, publishing in Supportive Care in Cancer, enrolled 44 cancer survivors who still had neuropathy symptoms at least three months after finishing potentially neurotoxic chemotherapy. Participants were randomized 2:1 — 29 to laser, 15 to sham — and treated twice weekly for twelve sessions over six weeks, with assessments at baseline, six weeks and twelve weeks.¹

The group was 61 percent female with a mean age of about 62. Just under half had colorectal cancer and about a third had breast cancer; a mean of roughly fifteen months had passed since chemotherapy. Neuropathy was grade 1 in 64 percent and grade 2 in 36 percent — that is, mild to moderate.¹

Who was screened out

The trial listed six specific exclusions, and they are worth reading as a description of who was not in the room.¹

• Anyone unable to lie supine for a thirty-minute period.
• Anyone with an open wound or ulcer over the treatment area.
• Anyone with a clinical diagnosis of peripheral neuropathy from another cause. The paper notes that diabetes without neuropathy was not itself an exclusion — but diabetes with neuropathy was, because that is a second cause.
• Anyone with uncontrolled psychiatric illness or cognitive dysfunction that could interfere with completing assessments.
• Anyone with a life expectancy under three months.
• Anyone using a concurrent complementary therapy for neuropathy during the study.

Read together, this describes a relatively well, relatively mobile group with a single identified cause of neuropathy, intact skin on the feet, no competing treatments running alongside, and mild to moderate severity. That is a clean trial population. It is not the population that walks into a neuropathy clinic with type 2 diabetes, an old foot ulcer, three prescriptions for nerve pain and fifteen years of symptoms.

What the response rates showed, and in what order

Response rates were 48 percent in the laser group and 53 percent in the sham group at six weeks, and 45 percent and 33 percent respectively at twelve weeks.¹ Stated plainly: the sham group responded slightly more often at the end of treatment, and the two arms separated only at follow-up, when the laser group held its gains and the control group’s declined.

That finding must stay on the page. It also has to be read with three facts attached.

First, this was a non-comparative trial by design. Each arm was tested against a fixed statistical threshold, not against the other arm. The published null hypothesis was that the true response rate is 5 percent, and the sample size was chosen to give 80 percent power if the true response rate on treatment were 20 percent.¹ The authors state explicitly that the design did not permit statistical comparison between the treatment and control arms.

Second, the control arm had fifteen people in it. In an arm of fifteen, one participant is worth about seven percentage points. The five-point gap at six weeks is therefore smaller than a single person’s response.

Third, the laser arm’s response rate did exceed the trial’s prespecified threshold at both time points, and reported side effects were low grade.¹ The authors’ own conclusion is measured: the result warrants evaluation in an appropriately powered phase III trial.

Why a sham arm is hard to build in a light-therapy trial

The paper describes its sham honestly. Sham participants got the identical visit schedule, the same eye mask, the same equipment and the same application points, with the laser aperture blocked by an opaque aluminum cover, so that the sensory experience would match the active treatment.¹ That is a careful design, and with a device delivering 8 milliwatts there is little heat or sensation to give the difference away.

Blinding was still incomplete, and the authors say so. The trial was single-blinded. The clinical neuropathy assessment was performed by an unblinded physician investigator, and the paper’s own limitations list names the unblinded clinical assessor and therapist as a weakness.¹ An unblinded assessor can shift a clinician-rated score in either direction.

None of this is a reason to discount the trial. It is a reason to hold both arms’ numbers loosely, including the six-week ones.

What this design could not capture

The authors list the limitations themselves: small sample size, a short intervention period, the unblinded assessor and therapist, and unavoidable delays to study visits caused by COVID-19 restrictions. They also note that no neurophysiological testing was performed because of resource constraints, and suggest it as an objective measure for a future trial.¹

Three further things follow from the design rather than from any fault in it. The trial tested laser alone, so it cannot say anything about laser used alongside metabolic correction, nutritional repletion or exercise. Follow-up stopped at twelve weeks, which is six weeks after the last session, so nothing in it speaks to durability beyond that. And with no nerve conduction testing, the trial measured symptoms and function rather than the nerve itself.

The NEUROLIGHT pilot trial: 60 patients, a class 4 laser, 2026

The second trial is the one that actually used a class 4 device, and it is a pilot without a control group.

Who was studied

Claes and colleagues, publishing in Lasers in Medical Science, treated 60 cancer patients with chemotherapy-induced peripheral neuropathy at Jessa Hospital in Hasselt, Belgium, between February 2022 and November 2023. Twenty-eight received six sessions at 6 joules per square centimeter and thirty-two received six sessions at 8 joules per square centimeter, twice weekly over three weeks.²

Most participants were women, with mean ages around 61 to 64. Breast cancer was the most common primary, followed by colorectal, head and neck, ovarian, endometrial, bladder, lung and prostate.²

Who was screened out

The eligibility rules were narrower than they first appear. To be included, a patient had to have a physician diagnosis of chemotherapy-induced neuropathy, be at least 18, have had one of a specific list of neurotoxic agents — paclitaxel, docetaxel, oxaliplatin, cisplatin, thalidomide, bortezomib or vincristine — with the last dose at least two weeks earlier, and have a Fitzpatrick skin type between I and V.²

That last criterion excluded Fitzpatrick type VI, the most deeply pigmented skin. Pigment absorbs light, so this is a real limit on who the reported doses have been tested in.

The stated exclusions were two: interrupting more than two consecutive treatment sessions, and having had neuropathy symptoms before receiving chemotherapy.² That second one is the important one. It removes exactly the patient who arrives at a neuropathy clinic with pre-existing diabetic or idiopathic neuropathy that chemotherapy then made worse — a common and difficult presentation, and one this trial cannot speak to.

What moved and what did not

The modified Total Neuropathy Score improved significantly over time (P = 0.048), as did the six-minute walk test (P < 0.001), with walking distance improving about 13 percent in the lower-dose group and about 18 percent in the higher-dose group. Pain scores on the numeric rating scale improved over time (P < 0.001), with better scores in the lower-dose group (P = 0.034). Patient satisfaction improved (P = 0.003). No adverse events were reported.²

Not everything moved. There was no significant change in the FACT/GOG-NTX total score or in its neurotoxicity subscale, meaning the broader quality-of-life instrument did not register the same signal.²

That split between a walking test and a questionnaire is common in neuropathy research, and it is a practical argument for tracking what you can do — how far you can walk, how steady you are — rather than a single global score.

It is also worth noting that the lower dose, not the higher one, produced the better pain scores, and that the authors decline to name an optimal fluence on that basis.² That is the biphasic dose response showing up inside a single trial.

What this design could not capture

The central limitation is structural: both groups received photobiomodulation. There was no sham arm, so improvement over time cannot be separated from natural recovery, from regression to the mean, or from a placebo effect. The authors say this plainly and accept that a placebo effect could partly explain the results.²

They also report that the sample was too small to analyze results by chemotherapy type, number of cycles, time since chemotherapy ended, prior lines of neurotoxic treatment, or neuropathy-inducing comorbidities such as diabetes — and that the effect of concurrent drugs like duloxetine and pregabalin was not assessed.² In other words, the trial could not tell you whether a diabetic patient in the group did better or worse than a non-diabetic one.

Twenty of the sixty patients were lost to follow-up, twelve in the lower-dose group and eight in the higher-dose group.² That is a third of the sample, and it is a further reason to read the later time points cautiously.

How long does a course need to be?

The trajectory in the sham-controlled trial is the most practically useful thing on this page. The laser arm did not lead at six weeks. It led at twelve.¹

Two readings are available and the trial cannot distinguish between them. Either the laser effect takes longer to appear than a treatment course lasts, or the control group’s early response was a short-lived placebo response that faded on schedule while the laser group’s did not. Both are consistent with the numbers.

Either way, the practical implication is the same: judging a course of photobiomodulation at the moment the last session ends is judging it too early. It also means follow-up length is a fair question to ask of any trial in this field. The sham-controlled trial stopped at twelve weeks. The class 4 pilot collected data at baseline, after the six sessions, three weeks later, and again at six months and one year — but with no control arm, its long-term numbers cannot be attributed to the laser.^1,2

Diabetic peripheral neuropathy: the gap, and who the trials there screened out

Diabetic peripheral neuropathy is the clearest gap in this evidence. Neither trial above enrolled that population, and the mechanisms differ: metabolic and microvascular injury varies between patients in a way that a single fixed protocol is unlikely to address uniformly. Several of those drivers are covered in our review of the hidden drivers behind peripheral neuropathy.

Two registered sham-controlled trials, and what they excluded

Laser trials in diabetic neuropathy have been registered and run. Two sham-controlled trials of the same 635-nanometer, three-diode, 17-milliwatt device were registered on ClinicalTrials.gov, both applying the laser fifteen minutes per foot, twice weekly for six weeks.^4,5

The first completed with 30 participants.⁴ The second was terminated because it could not recruit, after enrolling 18; summary results are posted on its registry record.⁵ Neither is a peer-reviewed publication, and neither is large enough to settle anything. What they do document precisely is who was allowed in.

Both protocols required foot pain that was chronic, bilateral, and roughly symmetrical between the two feet, rated at least 50 on a 0–100 visual analog scale, on a stable diabetes medication regimen for the preceding 30 days.^4,5

The exclusions are the striking part. Across the two records, participants were excluded for any of the following:^4,5

• Foot pain that was unilateral or noticeably different between the two feet.
• Pain rated below 50 on the visual analog scale — that is, milder cases.
• Foot pain not definitively attributed to diabetes, or attributed to diabetes plus something else.
• Serious organ disease or other serious primary disease.
• Diabetic ketosis, ketoacidosis or severe infection within the previous two weeks.
• An active chronic pain condition — the second record names chronic fatigue syndrome, fibromyalgia, endometriosis, inflammatory bowel disease, interstitial cystitis and peripheral vascular disease.
• Cancer, or treatment for cancer, in the previous six months.
• An active infection, wound or other external trauma anywhere on the treatment area.
• Previous surgery or an implanted device for diabetic neuropathy foot pain.
• Analgesics or NSAIDs within seven days; antidepressants within 30 days; gabapentin, pregabalin, tramadol or opioid medicines within 30 days; local anesthetic injections within 30 days.
• Ongoing litigation or disability benefits related to the study parameters.

Why that matters for a patient with metabolic disease

Line those criteria up against a real clinic waiting room. A patient with peripheral vascular disease is out. A patient with a healing ulcer is out. A patient whose neuropathy is part metabolic and part something else is out. A patient with fibromyalgia alongside their neuropathy is out. A patient on gabapentin or pregabalin — which is a large share of people who have been treated for painful neuropathy — is out unless they stop for a month. A patient whose pain is bad in one foot and mild in the other is out.

This is not sharp practice by the investigators. Trials are built this way on purpose, to reduce noise and isolate a single effect. But it has a consequence that gets skipped over constantly: a modest or null result in a population selected this tightly does not establish that the treatment fails in the patients who were screened out. It establishes what happened in the patients who were let in.

The patients who were screened out here — vascular disease, unstable glycemic control, open wounds, multiple pain conditions, polypharmacy, mixed causes — are precisely the patients a metabolic neuropathy practice sees most days. The evidence is genuinely silent about them. Silence is not a negative finding, and it is not a positive one either.

Coverage is a payer decision, not a clinical finding

A national coverage determination in effect since October 24, 2006 states that infrared therapy devices are not covered by Medicare for treating diabetic or non-diabetic peripheral sensory neuropathy, or wounds or ulcers of the skin and subcutaneous tissues, including for pain arising from those conditions.^6,7

The determination is specific about what it is describing. It defines an infrared therapy device as an array of juxtaposed infrared diodes affixed to a flexible pad held in contact with the skin, which can also produce local warming as a secondary effect.⁶ That is a different piece of equipment from a laser, and the determination was written about the evidence for those pad devices.

It is a payer decision about a device category, not a clinical conclusion about laser photobiomodulation, and it should not be read as either an endorsement or a verdict. Because it dates from 2006 it also predates both trials on this page. Local coverage rules may differ, and nothing here is a benefits determination for any individual.

Where a service is not covered, patients sign an Advance Beneficiary Notice before it is provided, so that the financial side is settled in writing in advance rather than discovered afterward. It is fair to ask any clinic which device it is using and which coverage language it is relying on.

How light-based therapy fits into an evaluation-first plan

Class 4 photobiomodulation, class 3B cold laser, and whole-body infrared are offered here as part of a plan built around whichever driver the evaluation identifies. They are not offered as nerve regeneration or reversal, and no success rate is published for them.

Before any of it is discussed, the evaluation looks for which mechanism is active. Electrodiagnostic testing (EMG/NCS) is performed on site, and VNG (videonystagmography) is available as a diagnostic test of inner-ear balance function when dizziness or unsteadiness is part of the picture — it is a test, never a treatment.

The published trials tested light on its own, which is the only way to isolate its effect but not the way neuropathy is usually treated. Here, light-based therapy sits alongside metabolic and nutritional care aimed at the driver itself. That combination has not been tested in a randomized trial, and saying so is more useful than implying it has.

Orthobiologic injections (PRP and BMAC) are offered here as well.

What all of this adds up to is a conversation rather than a protocol. The risks of photobiomodulation reported in these trials were low — mild, low-grade events in one and none in the other — and the potential benefit in a patient like yours is genuinely uncertain. Both halves of that sentence belong in the discussion before anyone starts a course of treatment.

What to ask before you commit to a course of treatment

• Which neuropathy driver do you believe is dominant in my case, and what did you base that on?
• Is the plan supported by trial evidence in a population like mine, or extrapolated from a different one?
• If it is extrapolated, what specifically about my case makes you think it transfers?
• How many sessions, over what period, at what wavelength and what energy density?
• When will we judge whether it is working, and why then rather than at the last session?
• What function will we measure, not just what pain score?
• Which device is this, what class is it, and what coverage language applies to it?

Where we are and how to start

Regenerve is located at 4477 Woodson Rd #104, St. Louis, MO 63134, minutes from St. Louis Lambert International Airport, and we see patients from across the St. Louis region, Missouri and Illinois. You can call or text (314) 886-5902, or email info@regenerve.com.

The free Nerve Damage Score is a five-question starting point for the driver question, which is the question that decides whether light-based therapy belongs in your plan at all.

Frequently asked questions

Is the evidence for photobiomodulation in neuropathy strong enough to rely on?

On its own, no — there are two published trials in established neuropathy, both in chemotherapy-induced cases, one small and sham-controlled and one with no control group at all.^1,2 That is a reason to treat it as one component of a plan aimed at an identified driver, rather than as the plan. It is not a reason to call it disproven, because the trials that exist have not studied most of the people asking the question. See the treatments offered here.

Does that evidence transfer to diabetic neuropathy?

Not automatically. Diabetic peripheral neuropathy involves metabolic and microvascular drivers that vary between patients, and neither published trial on this page enrolled that population. The registered diabetic neuropathy laser trials that do exist excluded peripheral vascular disease, open wounds on the feet, recent ketoacidosis and patients taking common nerve pain medications, so they say little about a complex metabolic patient either.^4,5 See how diabetic peripheral neuropathy is approached here.

The sham group did better at six weeks. Does that mean the laser did nothing?

It means the trial did not show a laser advantage at the end of treatment, which is worth knowing. It does not mean nothing happened, for three reasons: the trial was designed as non-comparative and its authors state it could not statistically compare the arms; the control arm had only fifteen people, so a five-point gap is smaller than one participant’s response; and by twelve weeks the laser group had held its response while the control group’s had fallen.¹ See which specialist to see when neuropathy has not improved.

How is photobiomodulation different from Qutenza?

They are unrelated mechanisms with very different evidence. Qutenza (capsaicin 8% patch) is FDA-approved in adults only for neuropathic pain from postherpetic neuralgia and from diabetic peripheral neuropathy of the feet, and any other use is off-label. It is applied in clinic by a clinician, never dispensed for home use, and repeated no more often than every three months. See how Qutenza is used in clinic.

Will Medicare cover light therapy for neuropathy?

A national coverage determination in effect since October 2006 makes infrared therapy devices non-covered for peripheral sensory neuropathy, wounds and ulcers.⁶ That determination describes arrays of infrared diodes on a flexible pad, not laser photobiomodulation, and coverage is a payer decision rather than a statement about whether something works. Where a service is not covered, an Advance Beneficiary Notice is signed before treatment. See contact us with coverage questions.

Sources

1. Teng C, Egger S, Blinman PL, Vardy JL. Evaluating laser photobiomodulation for chemotherapy-induced peripheral neuropathy: a randomised phase II trial. Supportive Care in Cancer. 2022;31(1):52. https://pmc.ncbi.nlm.nih.gov/articles/PMC9758032/ (44 cancer survivors at least 3 months after neurotoxic chemotherapy; randomized 2:1, 29 laser and 15 sham; class 2M continuous diode laser, 8 mW through a 3.2 mm aperture, 1–2 J per point at 26 points, twice weekly for 12 sessions; response rates 48% laser and 53% sham at 6 weeks, 45% and 33% at 12 weeks; non-comparative design; null hypothesis of a 5% true response rate; sham delivered with the aperture occluded by an opaque aluminium cover; limitations include small sample, short intervention period and unblinded clinical assessor and therapist).
2. Claes M, Lodewijckx J, Robijns J, Hermans S, Peeters P, Mebis J. Evaluating the efficacy of photobiomodulation therapy in the management of chemotherapy-induced peripheral neuropathy: a pilot trial (NEUROLIGHT trial). Lasers in Medical Science. 2026;41(1):57. https://pmc.ncbi.nlm.nih.gov/articles/PMC12988979/ (60 cancer patients with chemotherapy-induced peripheral neuropathy at Jessa Hospital, Hasselt, Belgium, February 2022 to November 2023; class IV MLS M6 laser, 905 nm and 808 nm, peak power 25 W and 1.1 W, power density 0.168 W/cm², 150 cm² beam spot; 6 sessions at 6 J/cm² (n = 28) or 8 J/cm² (n = 32); Fitzpatrick skin types I–V only; exclusions were interruption of more than two consecutive treatments and neuropathy symptoms preceding chemotherapy; mTNS P = 0.048, 6MWT P < 0.001, NRS pain P < 0.001 favoring the 6 J/cm² group P = 0.034, no significant difference in FACT/GOG-NTX total score or neurotoxicity subscale; no control group; 20 of 60 lost to follow-up).
3. Huang YY, Chen AC, Carroll JD, Hamblin MR. Biphasic dose response in low level light therapy. Dose-Response. 2009;7(4):358–383. https://pmc.ncbi.nlm.nih.gov/articles/PMC2790317/ (low levels of light stimulate and repair tissue more effectively than higher levels, described by the Arndt-Schulz curve; the difficulty of choosing among wavelength, fluence, power density, pulse structure and treatment timing has produced both negative and positive studies).
4. ClinicalTrials.gov. Study of Low Level Laser Therapy to Treat Diabetic Peripheral Neuropathy Foot Pain (NCT02461225). Erchonia Corporation. https://clinicaltrials.gov/study/NCT02461225 (double-blind, placebo-controlled randomized evaluation of the Erchonia FX-635; completed with 30 participants; three 17 mW 635 nm diodes, 15 minutes per foot, twice weekly for 6 weeks; full inclusion and exclusion criteria as summarized above).
5. ClinicalTrials.gov. An Evaluation of the Effect of Low Level Laser Therapy on Diabetic Peripheral Neuropathy Pain (NCT04006392). Erchonia Corporation. https://clinicaltrials.gov/study/NCT04006392 (double-blind, placebo-controlled randomized evaluation of the Erchonia FX-635; terminated for inability to recruit after enrolling 18 participants; results posted March 14, 2023; exclusions include peripheral vascular disease, active infection or wound on the treatment area, serious organ disease, and recent diabetic ketosis or ketoacidosis).
6. Centers for Medicare & Medicaid Services. National Coverage Determination 270.6: Infrared Therapy Devices. Effective October 24, 2006. https://www.cms.gov/medicare-coverage-database/view/ncd.aspx?ncdid=315&ncdver=1 (infrared and near-infrared light and heat, including monochromatic infrared energy, non-covered for diabetic and non-diabetic peripheral sensory neuropathy, wounds and ulcers of the skin and subcutaneous tissues, including pain arising from those conditions; the determination describes an array of juxtaposed infrared diodes affixed to a flexible pad held against the skin).
7. Centers for Medicare & Medicaid Services. Decision Memo for Infrared Therapy Devices (CAG-00291N). 2006. https://www.cms.gov/medicare-coverage-database/view/ncacal-decision-memo.aspx?proposed=N&ncaid=176 (the national coverage analysis underlying NCD 270.6).