Red Light Therapy for Diabetes: Blood Sugar, Neuropathy and Complications

TL;DR

• A 2024 randomised study from City, University of London and UCL found that 15 minutes of 670nm red light exposure on the back reduced total blood glucose levels by 27.7% and peak glucose spiking by 7.5% over a two-hour oral glucose tolerance test. The study was led by Professor Glen Jeffery, the same researcher behind the landmark UCL colour vision improvement study, and published in the Journal of Biophotonics.
• The mechanism is mitochondrial: 670nm red light stimulates cytochrome c oxidase in cellular mitochondria, increasing ATP production and driving increased cellular glucose consumption. Higher energy demand in cells pulls more glucose out of the bloodstream.
• The honest position: the blood sugar study was conducted in 30 healthy adults without diabetes. Large-scale clinical trials in people with Type 1 and Type 2 diabetes are needed before red light therapy can be positioned as a diabetes management tool. It is best approached as a complementary support alongside medical management, not a replacement for prescribed medications, diet, or blood glucose monitoring.
• Beyond blood sugar, red light therapy has a more established evidence base for two major diabetic complications: diabetic peripheral neuropathy (nerve damage causing pain and numbness in the feet and hands) and diabetic wound healing (particularly foot ulcers, which are among the most serious complications of diabetes).
• The same Professor Jeffery lab that conducted the blood sugar study has documented that 670nm red light improved outcomes in an animal model of diabetic retinopathy, adding a third diabetic complication where photobiomodulation research shows promise.

Diabetes affects an estimated 1.5 million Australians and is one of the fastest-growing chronic conditions in the country. For people managing Type 1 or Type 2 diabetes, the daily challenge of blood glucose control is compounded by the long-term risk of serious complications including peripheral neuropathy, foot ulcers, retinopathy, and cardiovascular disease. The search for safe, non-pharmacological approaches to complement medical management is active and ongoing.

Red light therapy has attracted genuine scientific interest for both blood sugar regulation and diabetic complications, with the most significant finding coming from a 2024 randomised study by researchers at City, University of London and UCL. This guide covers the blood sugar research in detail, the mechanisms behind it, the evidence for diabetic complications, and how to approach photobiomodulation as a complementary tool alongside standard diabetes care.

The UCL Blood Sugar Study: What It Found

The most significant finding in red light therapy and diabetes research is a 2024 randomised study conducted by Dr Michael Powner at City, University of London and Professor Glen Jeffery at UCL's Institute of Ophthalmology, published in the Journal of Biophotonics (DOI: 10.1002/jbio.202300521).

Thirty healthy participants with no known metabolic conditions were randomised into two groups: 15 receiving 670nm red light exposure and 15 receiving placebo (no light). Participants received red light on their backs for 15 minutes, 45 minutes before performing an oral glucose tolerance test (drinking glucose dissolved in water). Blood glucose was then measured every 15 minutes over the following two hours.

People who received red light exposure showed a 27.7% reduction in total blood glucose levels over the two hours, and a 7.5% reduction in peak blood glucose spiking compared to the placebo group. These are meaningful reductions in the glucose response to an oral glucose load.

Professor Jeffery, who is also the researcher behind the landmark UCL colour vision improvement study using 670nm light, commented: "It is clear that light affects the way mitochondria function and this impacts our bodies at a cellular and physiological level. Our study has shown that we can use a single, 15-minute exposure to red light to reduce blood sugar levels after eating. While this has only been done in healthy individuals in this paper, it has the potential to impact diabetes control going forward, as it could help to reduce potentially damaging glucose spikes in the body after meals."

How Red Light Reduces Blood Glucose: The Mechanism

The mechanism behind the blood glucose effect is the same fundamental photobiomodulation pathway documented across all red light therapy applications, but with a specific metabolic consequence that is particularly relevant to glucose management.

670nm red light is absorbed by cytochrome c oxidase in the mitochondrial respiratory chain. This increases mitochondrial ATP production, providing cells with more energy. The increased cellular energy demand drives greater consumption of glucose from the bloodstream to fuel the enhanced ATP synthesis. The net result is measurably lower blood glucose as more glucose is drawn into cells for energy production.

Professor Jeffery's team also highlighted a broader implication of this mechanism. They noted that we now live in a world where blue light is dominant in indoor environments because modern LED lighting emits heavily toward the blue end of the spectrum with very little red. In contrast, pre-1990 incandescent lighting had a balance of red and blue similar to sunlight. The researchers suggest that the shift to blue-dominant LED environments may be reducing mitochondrial function at a population level by starving cells of the red light wavelengths that support optimal ATP production. Professor Jeffery commented: "Long-term exposure to blue light is potentially toxic without red. Blue light on its own impacts badly on physiology and can drive disrupted blood sugars that may in the long run contribute to diabetes and undermine health spans."

Important Caveats About the Blood Sugar Research

The 27.7% blood glucose reduction is a compelling finding, but several important limitations must be understood before considering red light therapy as a diabetes management tool.

• The study was conducted in healthy adults without diabetes. Whether the same glucose-reducing effect occurs in people with Type 1 or Type 2 diabetes, where glucose regulation is fundamentally impaired by insulin deficiency or resistance, has not yet been established in clinical trials.
• This was a single exposure study. The research examined the effect of one 15-minute session before one glucose load. The cumulative effect of regular sessions over weeks or months in diabetic patients is the subject of ongoing research.
• The study used back irradiation specifically. The 670nm light was applied to the participants' backs, not a targeted area. The abscopal effect (systemic impact from localised treatment) was the proposed mechanism for the whole-body glucose response.
• Sample size was 30 participants. Larger randomised controlled trials in diabetic populations are needed to confirm the effect size and establish clinical protocols.

Red light therapy should be approached as a complementary approach alongside prescribed diabetes medications, dietary management, and blood glucose monitoring - not as a replacement for any component of standard diabetes care.

Red Light Therapy for Diabetic Complications

Beyond blood sugar regulation, the more established evidence base for red light therapy in diabetes concerns the management of serious diabetic complications where photobiomodulation's anti-inflammatory, wound healing, and neurological mechanisms are directly relevant.

Diabetic Peripheral Neuropathy

Diabetic peripheral neuropathy (DPN) is nerve damage caused by sustained high blood glucose damaging the small blood vessels that supply peripheral nerves. It affects up to 50% of people with diabetes and produces the characteristic symptoms of numbness, tingling, burning pain, and loss of sensation in the feet and hands. It is also the primary driver of diabetic foot ulcers, as loss of protective sensation allows injuries to go unnoticed.

Photobiomodulation addresses DPN through several mechanisms: improved microcirculation to the nerve supply, direct support for Schwann cell function and myelin maintenance, reduction of the neuroinflammation that accelerates nerve damage, and mitochondrial energy restoration in metabolically stressed neural tissue. Research has documented improvements in nerve conduction velocity, pain scores, and sensory function in DPN patients receiving consistent LLLT, consistent with the evidence for carpal tunnel syndrome and other peripheral nerve compression conditions where the mechanisms overlap.

Diabetic Wound Healing

Diabetic foot ulcers affect approximately 15% of people with diabetes over their lifetime and are the leading cause of non-traumatic lower limb amputation in Australia. They are notoriously difficult to heal because diabetes impairs virtually every component of the wound healing process: poor circulation reduces oxygen delivery, high glucose impairs immune function, neuropathy allows continued trauma to unhealed wounds, and impaired fibroblast activity slows collagen production.

Photobiomodulation addresses multiple aspects of this healing impairment simultaneously. The 2025 study on wound healing confirmed that red light significantly upregulated VEGF (vascular endothelial growth factor) for angiogenesis, stimulated fibroblast collagen synthesis, and promoted macrophage M1 to M2 polarisation to shift wounds from the inflammatory to the repair phase. Multiple clinical studies document faster diabetic wound closure rates when red light therapy is added to standard wound care. Diabetic wound management should always be supervised by a healthcare provider.

Diabetic Retinopathy

Diabetic retinopathy is damage to the blood vessels of the retina caused by sustained high blood glucose, and is the leading cause of preventable blindness in working-age Australians. The retina has among the highest mitochondrial density of any tissue in the body, making it particularly vulnerable to the mitochondrial dysfunction that diabetes drives.

The same Professor Jeffery lab at UCL that conducted the blood sugar study has documented in animal research that 670nm red light applied to mice improved outcomes in a model of diabetic retinopathy. The mechanism aligns directly with the blood sugar finding: improved mitochondrial function in retinal cells through cytochrome c oxidase activation supports the energy-intensive phototransduction process and may reduce the vascular damage that drives retinopathy progression. This is the same 670nm wavelength used in the glasses product specifically designed for ocular delivery at safe irradiance levels.

How to Use Red Light Therapy Alongside Diabetes Management

• Inform your diabetes care team. Red light therapy should be discussed with your GP, endocrinologist, or diabetes educator before starting, particularly if you are on insulin or medications that affect blood glucose, as the glucose-lowering effect documented in the UCL study could theoretically interact with medication timing.
• For blood sugar support: The UCL protocol applied 670nm light to the back for 15 minutes before meals. Consistent morning sessions covering the back and torso align most closely with the research. The closer your device wavelength is to 670nm, the more directly you are targeting the documented mechanism.
• For neuropathy: Target the affected areas directly, typically the feet and lower legs, with sessions of 10 to 15 minutes three to five times per week. Both red (660nm) and near-infrared (850nm) wavelengths are relevant for peripheral nerve support.
• For wound healing: Follow the wound healing protocol: non-contact treatment from 2 to 5cm above open wounds, progressing to closer range once wounds are closed. Always under medical supervision for diabetic foot ulcers.
• Monitor blood glucose carefully when starting. If you are on insulin or glucose-lowering medications, monitor your blood glucose more closely when first incorporating red light therapy into your routine, as the additive glucose-lowering effect could affect medication dosing requirements over time.
• Consistency over weeks. The cumulative mitochondrial restoration, anti-inflammatory, and circulatory effects that are most relevant to diabetes complications require consistent sessions over 8 to 12 weeks to produce meaningful change.

StreamShop Devices for Diabetes Support

Red Light Therapy Laser Mat With 1064nm: Closest to the Study Protocol

StreamShop's red light therapy laser mat with 1064nm combines LED and VCSEL laser technology across six wavelengths including 660nm, 830nm, 850nm, 940nm, and 1064nm at 110 mW/cm² over a 1.8m x 80cm surface. For the blood sugar mechanism documented in the UCL study, lying on the laser mat covers the full back and posterior body with red and NIR wavelengths, delivering the large-area back irradiation that produced the 27.7% glucose reduction in the research protocol. The 660nm wavelength is the closest LED equivalent to the 670nm used in the study. Whole-body sessions address systemic mitochondrial function across all tissues simultaneously, which is relevant to the broader metabolic picture in diabetes. For neuropathy affecting the posterior legs and feet, lying on the mat with the legs and feet in direct contact delivers NIR to the affected peripheral nerve pathways.

SS100 Class IIa Medical Grade Panel

StreamShop's SS100 class IIa medical grade panel delivers 160 mW/cm² or above at 15cm across nine wavelengths including 660nm, 810nm, 830nm, 850nm, and 940nm through a 30-degree focusing lens. For people wanting the highest available irradiance for back and torso sessions aligned with the blood sugar research protocol, the SS100 positioned at the back at 10 to 15cm delivers a powerful multi-wavelength dose covering the large treatment area used in the UCL study. The nine-wavelength configuration covering both red and the full NIR range provides comprehensive coverage for both the blood sugar mechanism and the neuropathy and circulation applications relevant to diabetes complications. As a class IIa ARTG-listed medical grade device, it meets the highest regulatory standard for at-home therapeutic devices in Australia.

Red Light Therapy Torch With 900nm: Targeted Neuropathy and Foot Care

StreamShop's red light therapy torch with 900nm delivers five wavelengths including 660nm and 900nm NIR in a handheld format with 10Hz pulse mode for pain management. For diabetic peripheral neuropathy affecting the feet and hands, the torch is the most practical device for targeted treatment of the specific areas of numbness, tingling, and pain. The handheld format allows systematic coverage of the full foot including the sole, dorsum, and ankle, and the lower leg where peripheral nerve damage is most pronounced. The 10Hz pulse mode specifically supports the pain management and nerve function protocols most relevant to neuropathy. For people with diabetic foot complications under medical care, the torch can be used under GP guidance as an adjunct to wound care once wounds are closed.

Red Light Therapy Glasses for Eyesight: Diabetic Retinopathy Support

StreamShop's red light therapy glasses for eyesight deliver 670nm at 4 mW/cm² across 48 LEDs in a 15-minute wearable session. For people with diabetes managing retinal health, these glasses deliver the exact 670nm wavelength used in Professor Jeffery's research at UCL - the same lab that documented both the blood sugar effect and the diabetic retinopathy animal model improvements. The 670nm wavelength stimulates cytochrome c oxidase in the mitochondria-dense retinal cells, supporting the cellular energy production that retinal tissue depends on and that is compromised by the vascular damage of diabetic retinopathy. At 4 mW/cm², the irradiance is specifically calibrated for safe ocular delivery. Consult your ophthalmologist before starting if you have diagnosed diabetic retinopathy or are under active ophthalmic care for diabetes-related eye disease.

Frequently Asked Questions

Can Red Light Therapy Help With Diabetes?

A 2024 randomised study from City, University of London and UCL found that 15 minutes of 670nm red light on the back reduced blood glucose by 27.7% and peak spiking by 7.5% in healthy adults. The study was not conducted in diabetic patients and larger clinical trials are needed. Red light therapy also has evidence for diabetic complications including peripheral neuropathy, wound healing, and retinopathy. It should be used as a complementary approach alongside standard diabetes medical management.

Does Red Light Therapy Lower Blood Sugar?

The UCL study documented a 27.7% reduction in blood glucose response to an oral glucose load after a single 15-minute 670nm session in healthy adults. The mechanism is mitochondrial: increased ATP production drives greater cellular glucose consumption, pulling glucose from the bloodstream. This research has not yet been replicated in clinical trials with diabetic patients. Do not adjust diabetes medications based on red light therapy use without discussing with your GP or endocrinologist.

Can Red Light Therapy Help With Diabetic Neuropathy?

Yes, with a meaningful evidence base. Photobiomodulation improves microcirculation to peripheral nerves, supports Schwann cell function and myelin maintenance, reduces neuroinflammation, and restores mitochondrial energy in damaged neural tissue. Research documents improvements in nerve conduction velocity, pain scores, and sensory function in peripheral neuropathy patients. The torch and laser mat are the most practically relevant devices for targeting affected feet and lower legs.

What Wavelength Is Best for Blood Sugar and Diabetes?

670nm is the specific wavelength used in the UCL blood sugar study and in Professor Jeffery's diabetic retinopathy research. It is the most directly evidence-aligned wavelength for the blood sugar mechanism. 660nm is the closest LED equivalent and is available across the SS range and laser mat. For neuropathy and wound healing, near-infrared at 850nm adds deeper tissue penetration relevant to peripheral nerve support.

Is Red Light Therapy Safe for People With Diabetes?

Yes, with appropriate medical oversight. Red and near-infrared light is non-ionising and safe at therapeutic doses. People on insulin or glucose-lowering medications should monitor blood glucose carefully when starting, as the additive glucose-lowering effect could theoretically affect medication requirements over time. Discuss with your GP before starting, particularly if you have active diabetic foot ulcers, retinopathy under treatment, or are on complex medication regimens. Red light therapy should complement, not replace, standard diabetes management.

Can Red Light Therapy Help Diabetic Foot Ulcers?

Yes, as an adjunct to standard wound care under medical supervision. Photobiomodulation addresses multiple aspects of the impaired healing in diabetic wounds simultaneously: VEGF upregulation for angiogenesis, fibroblast collagen synthesis, macrophage polarisation from inflammatory to repair phase, and improved microcirculation. Diabetic foot ulcers require appropriate clinical wound management including dressings, offloading, and vascular assessment. Red light therapy should be discussed with your treating team as a complementary addition to this care.