How Red Light Therapy Benefits Neuropathy, Myopathy and More
Analysis by Dr. Joseph Mercola
- Photobiomodulation, using specific wavelengths of red and near-infrared light, shows promise in treating neuropathy, myopathy and myopia by reducing inflammation, improving cellular function and slowing eye elongation
- Red light therapy has demonstrated effectiveness in slowing myopia progression in children, with studies showing reduced axial eye elongation and improved vision compared to conventional treatments
- Photobiomodulation therapy alleviates neuropathic pain by boosting mitochondrial function and reducing oxidative stress. It's particularly effective when combined with other treatments like exercise or electrical stimulation
- The optical window for light therapy ranges from 600 to 900 nanometers, with near-infrared light (around 800 to 810 nm) being especially beneficial for deep tissue penetration and mitochondrial health
- Red and near-infrared light exposure stimulates ATP and melatonin production in mitochondria, improving overall health. A general dosage guideline is 25 joules, typically achieved through 20-minute sessions
Red light therapy, also known as low-level light therapy (LLLT) or photobiomodulation, is a non-invasive treatment that uses specific wavelengths of red and near-infrared light to stimulate cellular function. This therapy has gained attention for its ability to promote healing, reduce inflammation and alleviate pain in various conditions.
The benefits of red-light therapy extend to several areas of health. For neuropathy, it helps reduce pain and improve nerve function by increasing blood flow and reducing inflammation. In cases of myopathy, red light therapy shows promise in enhancing muscle recovery and reducing muscle fatigue. Additionally, research suggests it may have positive effects on skin health, myopia, cognitive function and more.
Low-Level Red-Light Therapy: A Promising Approach for Myopia
Myopia, commonly known as nearsightedness, is becoming increasingly prevalent worldwide, especially among children. A study published in the British Medical Journal (BMJ) highlights the alarming rise in myopia rates.1 According to the research, the global prevalence of myopia has steadily increased from 24.32% in 1990 to 35.81% in 2023. Even more concerning, projections suggest this number could reach 39.80% by 2050.
This trend is particularly pronounced in certain demographics. East Asian populations show a higher prevalence at 35.22%, while urban areas see rates of 28.55%. Adolescents are especially affected, with a staggering 47% prevalence rate. These statistics underscore the urgent need for effective interventions to manage and prevent myopia progression in children. This is where innovative approaches like low-level red light therapy come into play.
Low-level red-light therapy (LLRL) offers a gentle approach that may be particularly suitable for children. A meta-analysis of several studies, published in Clinics and involving 685 patients with a mean age of 9.7 years, found that LLRL therapy was associated with better outcomes in two key measures of myopia progression: spherical equivalent refraction (SER) and axial length (AL) change.2
Compared to control groups, children receiving LLRL therapy showed a mean difference of 0.58 diopters in SER change and -0.33 mm in AL change. These numbers might seem small, but in the context of myopia progression, they represent significant improvements that could make a substantial difference in long-term eye health.
A comprehensive review of multiple studies also found that red light therapy, using wavelengths between 635 to 650 nanometers (nm) — a unit of measurement used to describe wavelengths of light — effectively reduces axial elongation of the eye and slows the increase in myopic spherical equivalent refraction, suggesting the nearsightedness is progressing more slowly.3
What's particularly exciting is that these benefits were observed in treatments ranging from just four weeks up to 24 months.
A Bright Solution for the Growing Problem of Myopia
Additional studies have found that repeated low-level red light (RLRL) therapy significantly slows down the elongation of the eye, which causes myopia, and improves vision compared to just wearing glasses.4 The treatment is simple: children look into a red-light device for three minutes, twice a day, five days a week. It's easy to do at home, and parents monitor their child's progress through an app.
Best of all, it doesn't have the side effects associated with other myopia treatments like atropine eye drops or orthokeratology lenses. The secret to red light’s profound effects on vision lies in how it interacts with your eyes at a cellular level.
Red-light therapy works by stimulating the production of dopamine in your retina, which acts as a "stop signal" for eye growth. It also increases blood flow to the choroid, the layer of blood vessels that nourishes your retina.5 A thicker choroid is associated with better eye health and less myopia progression.
Additionally, red light therapy reduces oxidative stress and inflammation in the eye, both of which are thought to play a role in myopia progression. By addressing these underlying factors, red light therapy doesn't just mask the symptoms of myopia — it helps to slow down or even halt its progression. This is a crucial difference from conventional treatments that only correct vision without addressing the underlying cause of myopia.
In several clinical trials, children who received red light therapy showed significantly less myopia progression than those who only wore glasses. On average, children treated with red light L had about 0.3 millimeters less eye elongation after 12 months compared to those who only wore glasses.6
Importantly, these studies found no serious side effects from the RLRL treatment. This safety profile, combined with its effectiveness, makes RLRL therapy an attractive option for parents concerned about their child's worsening myopia.
Photobiomodulation Offers Hope for Neuropathy Sufferers
If you're struggling with neuropathy, photobiomodulation (PBM) therapy, which refers to the therapeutic use of specific wavelengths of light, including red and near-infrared light, to stimulate biological processes in cells, may provide relief.
Recent research has shown that PBM is particularly effective when combined with other therapies, offering a powerful tool in managing neuropathic pain.7 The therapy works by boosting mitochondrial function, improving adenosine triphosphate (ATP) synthesis and reducing oxidative stress and inflammation.
These effects are especially beneficial for those dealing with peripheral neuropathy, where nerve damage causes pain, numbness and tingling sensations. Studies have demonstrated that PBM therapy helps alleviate these symptoms, offering you a drug-free alternative or complement to conventional treatments. The wavelengths used in PBM therapy, typically ranging from red to near-infrared light, target the affected nerves and promote healing at a cellular level.8
Integrating PBM with treatments like exercise or ultrasound therapy yields superior results compared to using these therapies alone. For instance, combining PBM with transcutaneous electrical nerve stimulation (TENS) has been found to significantly reduce pain scores and improve nerve function in carpal tunnel syndrome, a common form of neuropathy.9
Another study revealed that using PBM alongside wrist splinting led to reduced pain, enhanced hand grip strength and improved functional status in carpal tunnel patients.10 These combination therapies work synergistically to promote healing and restore function.
Beyond Neuropathy: PBM's Wide-Ranging Benefits for Neurological Health
While neuropathy relief is a significant benefit of PBM therapy, its potential extends far beyond peripheral nerve issues. Research has shown promising results in various neurological and neuropsychiatric disorders. For instance, PBM has demonstrated positive effects in managing symptoms of neurodegenerative diseases like Alzheimer's and Parkinson's.11
When combined with exercise, PBM therapy has shown promise in slowing disease progression and improving motor function in these conditions. In regard to mental health, PBM reduces anxiety and depressive behaviors when used alongside conventional treatments or environmental enrichment strategies.12
For stroke patients, combining PBM with other therapies like neuromuscular electrical stimulation led to improvements in cognitive function and mobility.13 This suggests PBM could be a valuable addition to your treatment plan if you're dealing with a range of neurological issues, not just neuropathy.
PBM Is a Powerful Health Optimization Tool
Indeed, PBM stands out as one of the most powerful health optimization tools available through modern technology. It’s crucial to understand a fundamental truth about human biology: your body requires regular exposure to red and infrared radiation, ideally on a daily basis. Nature designed us to receive this through sunlight on exposed skin, but modern lifestyles and seasonal changes often make this challenging.
Far infrared saunas offer an excellent alternative, providing both the necessary infrared radiation and valuable detoxification benefits. However, don’t make the mistake of thinking this replaces your need for movement. Daily walking, targeting 8,000 to 10,000 steps, remains essential for optimal health. If you’ve been free from vegetable oils for at least six months, performing these walks with minimal clothing around solar noon amplifies the benefits tremendously.
During winter months or poor weather, combining regular walking with infrared sauna sessions ensures you meet your body’s daily infrared requirements.
While saunas and sunshine provide invaluable full-body exposure to infrared radiation, PBM devices offer unique advantages for targeting specific areas needing therapeutic attention. This targeted approach proves particularly valuable when dealing with injuries or requiring focused treatment. The beauty of PBM lies in its precision — delivering optimal wavelengths at the therapeutic energy range where they are needed.
Understanding the Optical Window
More than half the wavelengths that come from the sun — 53% — are red, near-, mid- and far-infrared. Each of these wavelengths has important health benefits. Solar rays can be divided into three categories:
1.Ultraviolet (UVA, UVB and UVC), which account for 7% of the solar spectrum
2.Visible light (violet, indigo, blue, green, yellow, orange, red), ranging from 400 to 700 nanometers, which account for 39% of the spectrum
3.Invisible infrared (near-, mid- and far-infrared) light, ranging from 700 to 10,000 nanometers, which account for 54% of the spectrum
There's a term in biophysics called the optical window, which ranges from approximately 600 nanometers to 1,100 nanometers; 600 nanometers is red-orange. Around 700 nanometers you get into near-infrared, which becomes invisible and tops out roughly at 1,500 nanometers.
The ideal optical window is about halfway through the near-infrared range, between 600 to 900 nanometers. Within this optical window, the wavelengths are long enough to penetrate into the body and reach deep into the tissues, but they're not readily absorbed by hemoglobin, melanin and water.
Below 600 nanometers, the rays don’t penetrate very deep, and what does get into the body gets absorbed by hemoglobin and melanin. The optical window sweet spot is around 800 to 810 nanometers, which is classic near-infrared.
Near-Infrared Light Is Also Beneficial
One of the primary mechanisms behind the benefits of infrared exposure is the increase in ATP production in your mitochondria. Any cell that has mitochondria benefits from exposure to red and near-infrared light.
Another fantastic benefit of near-infrared exposure is melatonin production — 95% of melatonin is produced in your mitochondria in response to near-infrared light. The melatonin released by your pineal gland accounts for just 5% of the melatonin in your body.
Mitochondria are tiny organelles found in most of your cells responsible for cellular energy production, and mitochondrial dysfunction is a root cause of most chronic disease. Melatonin, meanwhile, is a very powerful antioxidant that reduces oxidative stress in your mitochondria. By mopping up free radicals created through normal cellular metabolism, melatonin reduces damage right where it’s needed the most — in the mitochondria — and helps them work optimally.
Melatonin also helps increase glutathione, which is a major detoxification agent. Importantly, none of the oral melatonin you take will ever make its way into your mitochondria. Oral melatonin helps regulate sleep, when taken at the appropriate time (in the evening, shortly before bed), but it will not do anything for the oxidative stress in your mitochondria. The only thing that will trigger that is near-infrared light on your bare skin.
In addition to increasing energy and melatonin production, other benefits of near-infrared exposure include triggering conversion of retinol (vitamin A) into retinoids, which your body needs for vitamin D production and the hemoglobin process, and boosting nitric oxide (NO) release, which increases blood circulation and vasodilation.
Dosing Suggestions
Spending time outdoors provides natural near-infrared exposure, but many people don’t get outside on a regular basis. Red and near-infrared therapy has also been shown to improve athletic performance and recovery, and for this effect, a PBM device is far more effective than sunshine, as the wavelengths are more targeted. This is also the case for targeting health conditions like myopathy and neuropathy.
For general health, you’re looking for the Goldilocks amount of red, near- and infrared light. With too little, you don't get a biological effect. With too much, you get into an inhibitory zone. So, what’s an ideal dose, in terms of an individual session? Most of the scientific literature uses anywhere from 5 joules to 50 joules. (Joule is a measurement of the energy delivered to the body in watts per second.)
As a general guidance, get as much full-spectrum sunlight from the outdoors as you can, and then use a dose of 25 joules, and take a day off every now and then. With a large panel, that would equate to 10 minutes on the front and 10 minutes on the back, for a total of 20 minutes.
There are no hard rules to go by when it comes to selecting a device, but in general, red is not going to penetrate as deep, and is typically more for skin disorders. Near-infrared will penetrate deeper, which is ideal for muscle recovery and cognitive enhancement. A mixed device gives you the best of both worlds, but you’ll need to spend about 50% more time using it, compared to a pure near-infrared device.
The effectiveness of PBM varies depending on factors such as wavelength, power density and treatment duration. When considering PBM for your neuropathy or other health concerns, consult with a health care provider experienced in this therapy. They can help determine the most appropriate parameters for your specific condition and guide you on how to integrate PBM for the best results.
As you explore PBM as a treatment option, keep in mind that it's typically most effective as part of a comprehensive approach to your health. Combining PBM with lifestyle modifications, such as a balanced diet and regular exercise, may enhance its benefits and your overall health.
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