Red Light and Near-Infrared Radiation: Powerful Healing Tools You’ve Never Heard of

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“Penetrating red light is possibly the fundamental anti-stress factor for all organisms. The chronic deficiency of such light is, I think, the best explanation for the deterioration which occurs with aging.” 
- Ray Peat

1. Preface

put on the red lightDuring the last summer, I spent quite a lot time reading Ray Peat’s articles. In many of his articles, Peat writes that darkness and blue light can be harmful for health, and red light is healthy.

Peat doesn’t give many references to justify those claims, but nevertheless, there exists a tremendous amount of study data supporting his views.

Certain wavelengths of electromagnetic radiation directly increase ATP-levels in the tissues, mainly by activating the mitochondrial enzyme cytochrome c oxidase (Cox). The most relevant wavelengths are 600-1000nm–in other words, red light and the penetrating shorter wavelengths of near-infrared radiation (NIR).[1-4]

On the other hand, blue light can inhibit the same enzyme (Cox), and this can lead to retinal damage and other problems.[5,6]


2. The health effects of red light and near-infrared radiation: The extent of the research

Red light’s positive effects on health are not a recent finding. The earliest reports on the topic have been published in the 19th century, the most well-known article being The Red Light Treatment of Small-Pox (1895) by Niels Finsen, who also got the 1903 Nobel Prize in medicine for his research regarding the health effects of light.[7]

In 1910, John Harvey Kellogg published his 200-page book Light Therapeutics, which included a large amount of information about the therapeutic usefulness of light therapy by incandescent light bulbs and
arc lights.[8, see also Appendix 3]

In this writing, I will focus on the contemporary research, most of which has been usually studied with low-level laser therapy devices (coherent light). Merely during this year (2013), dozens of controlled human studies have been published on this subject. Many of the studies are also placebo-controlled, because low-power near-infrared light is invisible and doesn’t emit heat.

According to the studies, many different illnesses can be treated with this kind of light therapy. Many of the results have been very encouraging. Here’s a list of some illnesses/problems that could be, according to the studies, effectively treated with red light and/or infrared:

  • Acne [9]
  • Achilles tendinitis [10]
  • Angina pectoris [11]
  • Aphthous stomatitis [12,13]
  • Body contouring [14,15]
  • Chemotherapy-induced oral mucositis [16-19]
  • Cholesterol levels [20,21]
  • Chronic autoimmune thyroiditis [22,23]
  • Chronic myofascial pain in the neck [24]
  • Chronic rhinosinusitis [25,26]
  • Depression/mood [27-29]
  • Dry mouth / xerostomia [30,31]
  • Dysmenorrea [32]
  • Fibromyalgia [33,34]
  • Gingivitis [35-38]
  • Hand-foot-and-mouth disease [39]
  • Herpes labialis [40-45]
  • Knee osteoarthritis [46-49]
  • Lateral epicondylitis [50]
  • Lymphedema (breast cancer-related) [51,52]
  • Macular degeneration, age-related [53]
  • Male androgenetic alopecia [54,55]
  • Myopia (degenerative/progressive) [56]
  • Onychomycosis [57]
  • Orofacial myofunctional conditions [58]
  • Photoaged skin [59,60]
  • Pressure ulcer [61]
  • Raynaud’s phenomenon [62]
  • Recovery from third molar extraction [63]
  • Restless legs syndrome [64,65]
  • Skin ulcers [66]
  • Sleep quality [67]
  • UVB-induced erythema (prevention of sunburns) [68]
  • Wound healing [69]

(The treatment methods vary between the studies, and this might explain varying study results.)

Many animal studies have also been conducted (see Appendix 2).


3. The health effects of red light and near-infrared radiation: A few examples of the clinical study results


Age-related macular degeneration

Researchers in the University of Heidenberg conducted a large trial of 200 subjects, in which they medicated elderly people with and without cataracts by near-infrared light (using low level laser).[53]

The intervention group was treated four times during two weeks. Placebo group was given a mock treatment.

Placebo didn’t affect subject’s vision, but of the patients getting infrared, 95% saw significant improvements in their vision. A large portion of the patients were able to see a few rows lower on the Snellen chart. The improved vision was maintained for 3-36 months after treatment.


Knee Osteoarthritis

Hungarian researchers studied the use of near-infrared light in knee osteoarthritis patients, in a double-blinded placebo controlled trial

Intervention group got infrared treatment on their affected joint twice a week, over a period of four weeks.The placebo group got a similar treatment of 100-fold lower intensity.[46]

In the intervention group, the pain scores were (on a scale from 1 to 10):
– 5.75 before the treatment
– 1.71 after the last treatment session
– 1.18 two months after completing the therapy

In the placebo group, the pain scores were:
– 5.62 before treatment
– 4.13 after the last treatment session
– 4.12 two months after completing the therapy


Labial herpes

The researchers of University of Vienna Medical School studied the usage of red light on labial herpes in a double-blind, placebo-controlled trial.[40]

The subjects were treated in a recurrence-free period. The intervention group were treated for 10 minutes daily for two weeks with visible red light (low-level laser). Placebo group got a similar treatment, but the laser wasn’t turned on. The subjects wore masks, so that they couldn’t see whether they were given the real treatment.

The patients were instructed to return to the department at the time of symptom recurrence. In the placebo group, the symptoms recurred. The median recurrence-free interval in the laser-treated group was 37.5 wk compared with 3 wk in the placebo group.


4. The systemic anti-inflammatory effect

Usually the red/near-infrared is applied locally to the treatable tissue. However, light also has systemic effects which seem to be transmitted mainly by circulation of blood. The researcher Natalya Zhevago has conducted an interesting study, in which the patients got some visible light and infrared to the sacral area (low back).[70] The given light was quite similar to sunlight, except that this light didn’t contain UV radiation or blue light, and the infrared portion was polarized. According to one study, polarization of light enhances the metabolic effect slightly.[71]

The subjects’ blood was analyzed after the treatment. The results were interesting. Subjects’ pro-inflammatory cytokines (TNF-α, IL-6 etc.) were dramatically reduced in the subjects, especially in those with initially high values. Also, the concentration of anti-inflammatory cytokines increased.[70]

A dramatic decrease in the level of pro-inflammatory cytokines TNF-α, IL-6, and IFN-γ was revealed: at 0.5 h after exposure of volunteers (with the initial parameters exceeding the norm), the cytokine contents fell, on average, 34, 12, and 1.5 times[...]

The effects were quite opposite to the typical effects of UV radiation, which increases TNF-α ja IL-6 and other pro-inflammatory cytokines.[72]

In human studies, large doses of IL-6 and TNF-α have been demonstrated to suppress peripheral thyroid hormone metabolism by decreasing T3 and increasing rT3.[73,74] We could also speculate, whether lack of sufficient therapeutic light could be one cause of the “rT3 dominance” and hypothyroid symptoms. In one study, half of the hypothyroid patients getting near-infrared treatment did not require any medication through the 9-month follow-up after the treatment period, establishing the importance of light for thyroid health.[22]


5. Light sources (laser, LED, light bulbs, heat lamps, sunlight)

“Many people who came to cloudy Eugene to study, and who often lived in cheap basement apartments, would develop chronic health problems within a few months. Women who had been healthy when they arrived would often develop premenstrual syndrome or arthritis or colitis during their first winter in Eugene.” – Ray Peat


red light therapyIn the studies conducted in recent years, red light and near-infrared have been studied mostly with coherent (laser) light devices. Some animal studies have also been conducted with light-emitting diodes (LEDs), eg. many of Janis Eells‘ studies.

Despite the fact that most of the studies used coherent light (laser), the coherence of the light is not a requirement for the therapeutic effects, so other light sources can be used therapeutically too. This was stated long ago by a leading researcher, Tiina Karu, and has been confirmed in a review article by Harvard researchers.[75] And as mentioned above, J. H. Kellogg has reported the immensely effective therapeutic use of incandescent bulbs as early as in 1910 (see Appendix 3).

When I was writing my Circadian Rhythms essay, I used to think about the possible explanations of the therapeutic effects of walking outdoors. Sunlight can increase the production of vitamin D and it can also suppress melatonin, but now we have a brand new mechanism to explain why it’s good to spend time outdoors.

A review article on this subject states that in central Europe, the amount of IR-A radiation is limited to 20mW/cm2, which is actually quite a good amount compared to the power of the devices used in the low-level laser studies.[1] On the other hand, the wavelengths aren’t optimized (to the absorption peaks) as in the laser studies, and daylight also contains UV radiation and blue light, which might reduce the benefits of red light. It should also be remembered that near-infrared radiation doesn’t penetrate through the clothes.

In the indoors, halogen lampsincandescent lamps and heat lamps are good sources of red and near-infrared light, at least if they’re held close enough to the skin. Heat lamps by Philips or Osram have quite a good spectrum with low amount of blue light, but a large amount of their power is emitted as warming IR-B radiation, and only ~12% of the power is emitted as the therapeutic wavelengths (600-1000nm). However, the heat lamps are often high power (up to 250W), so they still emit quite a significant amount of therapeutic wavelengths.

Because of the phase-out of incandescent lamps, it will soon be increasingly difficult to get typical incandescent lamps of sufficient power, so in the future heat lamps might be the most practical choice. It’s somewhat sad that the incandescent lamps are going to be replaced with compact fluorescent lamps (CFL), because they don’t usually emit significant amount of protective red and near-infrared light. This is the reason why some of the researchers, such as Richard Funk and Alexander Wunsch, who also appeared in the Bulb Fiction documentary, have stated that increase in the CFL usage might be harmful to citizens’ eyes.

The possible benefits of infrared saunas aren’t usually based on this aforementioned mechanism, because most of the saunas don’t emit the therapeutic wavelengths of 600-1000nm. For example, in one infrared sauna study, the sauna emitted infrared in the wavelength range of 5000-1000000 nanometres.

Theoretically, LEDs and lasers with optimized wavelengths would be the best option, but to this date, the products aren’t very cheap for the consumers. In theory, the optimal device emits only wavelengths of 700-950nm, so the light would be invisible and wouldn’t emit any heat, but still it would produce the therapeutic health benefits by increasing the function of Cox.


6. Conclusion

The important biological effects of red light were known even back in the 19th century, yet very few of the biologists seem to know about those findings nowadays. The knowledge of the physiological effects of light is mainly limited to blue light’s effects on circadian rhythm, yet the importance of red and near-infrared light is probably a more important topic for the public health.

The general therapeutic usefulness of red light reminds me of the therapeutic uses of thyroid hormone, the topic about which I’ve written before. This connection is actually quite logical, considering that thyroid hormone also increases Cox activity, by increasing the cardiolipin concentration in the mitochondria.[76,77]

Time will tell whether various treatments based on red and near-infrared light will gain popularity in the near future. But they should, because the study results are thoroughly so positive.



About the author

Vladimir Heiskanen2Vladimir Heiskanen of Finland has been researching and writing about health for several years. Currently a chemistry student at the University of Helsinki and a blogger since 2010, he has a keen interest in human biology, and has studied scores of books, reports and cutting-edge health websites, especially the work of Chris Masterjohn, Paul Jaminet, and Matt Stone. You can read all of his fascinating articles published at 180D HERE.



[1] Tiina I. Karu: Multiple Roles of Cytochrome c Oxidase in Mammalian Cells Under Action of Red and IR-A Radiation (2010)
[2] Karu et al: Irradiation with He-Ne laser increases ATP level in cells cultivated in vitro. (1995)
[3] Benedicenti et al: Intracellular ATP level increases in lymphocytes irradiated with infrared laser light of wavelength 904 nm. (2008)
[4] Lapchatk et al: Transcranial near infrared laser treatment (NILT) increases cortical adenosine-5′-triphosphate (ATP) content following embolic strokes in rabbits. (2010)
[5] Osborne et al: A hypothesis to suggest that light is a risk factor in glaucoma and the mitochondrial optic neuropathies (2008)
[6] Nick Lane: Are mitochondria the alpha and omega of retinal disease? (2006)
[7] Niels R. Finsen: The Red Light Treatment of Small-Pox (1895)
[8] John H. Kellogg: Light therapeutics; a practical manual of phototherapy for the student and the practitioner, with special reference to the incandescent electric-light bath (1910)
[9] Aziz-Jalali et al: Comparison of Red and Infrared Low-level Laser Therapy in the Treatment of Acne Vulgaris. (2012)
[10] Bjordal et al: A randomised, placebo controlled trial of low level laser therapy for activated Achilles tendinitis with microdialysis measurement of peritendinous prostaglandin E2 concentrations. (2006)
[11] Babushkina et al: Results Of 10-Year Use Of Low Intensity Laser Therapy And Conventional Treatment Of Patients With Stenocardia
[12] Anand et al: Low level laser therapy in the treatment of aphthous ulcer. (2013)
[13] De Souza et al: Clinical evaluation of low-level laser treatment for recurring aphthous stomatitis. (2010)
[14] Jackson et al: Low-level laser therapy as a non-invasive approach for body contouring: a randomized, controlled study. (2009)
[15] McRae&Boris: Independent evaluation of low-level laser therapy at 635 nm for non-invasive body contouring of the waist, hips, and thighs. (2013)
[16] Kuhn et al: Low-level infrared laser therapy in chemotherapy-induced oral mucositis: a randomized placebo-controlled trial in children. (2009)
[17] Gautam et al: Low level laser therapy for concurrent chemoradiotherapy induced oral mucositis in head and neck cancer patients – a triple blinded randomized controlled trial. (2012)
[18] Antunes et al: Phase III trial of low-level laser therapy to prevent oral mucositis in head and neck cancer patients treated with concurrent chemoradiation. (2013)
[19] Hodgson et al: Amelioration of oral mucositis pain by NASA near-infrared light-emitting diodes in bone marrow transplant patients. (2012)
[20] Jackson et al: Reduction in Cholesterol and Triglyceride Serum Levels Following Low-Level Laser Irradiation: A Noncontrolled, Nonrandomized Pilot Study (2010)
[21] Maloney et al: The reduction in cholesterol and triglyceride serum levels following low-level laser irradiation: a non-controlled, non-randomized pilot study (2009)
[22] Höfling et al: Low-level laser therapy in chronic autoimmune thyroiditis: a pilot study. (2010)
[23] Höfling et al: Low-level laser in the treatment of patients with hypothyroidism induced by chronic autoimmune thyroiditis: a randomized, placebo-controlled clinical trial. (2013)
[24] Gur et al: Efficacy of 904 nm gallium arsenide low level laser therapy in the management of chronic myofascial pain in the neck: a double-blind and randomize-controlled trial. (2004)
[25] Naghdi et al: A pilot study into the effect of low-level laser therapy in patients with chronic rhinosinusitis. (2013)
[26] Krespi&Kizhner: Phototherapy for chronic rhinosinusitis. (2011)
[27] Barrett&Gonzalez-Lima: Transcranial infrared laser stimulation produces beneficial cognitive and emotional effects in humans. (2013)
[28] Schiffer et al: Psychological benefits 2 and 4 weeks after a single treatment with near infrared light to the forehead: a pilot study of 10 patients with major depression and anxiety. (2009)
[29] Meesters et al: Prophylactic treatment of seasonal affective disorder (SAD) by using light visors: bright white or infrared light? (1999)
[30] Vidović Juras et al: Effects of low-level laser treatment on mouth dryness. (2010)
[31] Lončar et al: The effect of low-level laser therapy on salivary glands in patients with xerostomia. (2011)
[32] Shin et al: Skin adhesive low-level light therapy for dysmenorrhoea: a randomized, double-blind, placebo-controlled, pilot trial. (2012)
[33] Gür et al: Effects of low power laser and low dose amitriptyline therapy on clinical symptoms and quality of life in fibromyalgia: a single-blind, placebo-controlled trial. (2002)
[34] Gür et al: Efficacy of low power laser therapy in fibromyalgia: a single-blind, placebo-controlled trial. (2002)
[35] Obradović et al: Low-level lasers as an adjunct in periodontal therapy in patients with diabetes mellitus. (2012)
[36] Igic et al: Chronic gingivitis: the prevalence of periodontopathogens and therapy efficiency. (2012)
[37] Obradović et al: A histological evaluation of a low-level laser therapy as an adjunct to periodontal therapy in patients with diabetes mellitus. (2013)
[38] Makhlouf et al: Effect of adjunctive low level laser therapy (LLLT) on nonsurgical treatment of chronic periodontitis. (2012)
[39] Toida et al: Usefulness of low-level laser for control of painful stomatitis in patients with hand-foot-and-mouth disease. (2003)
[40] Schindl&Neumann: Low-intensity laser therapy is an effective treatment for recurrent herpes simplex infection. Results from a randomized double-blind placebo-controlled study. (1999)
[41] Muñoz Sanchez et al: The effect of 670-nm low laser therapy on herpes simplex type 1. (2012)
[42] Dougal&Lee: Evaluation of the efficacy of low-level light therapy using 1072 nm infrared light for the treatment of herpes simplex labialis. (2013)
[43] Ferreira et al: Recurrent herpes simplex infections: laser therapy as a potential tool for long-term successful treatment. (2011)
[44] de Carvalho et al: Effect of laser phototherapy on recurring herpes labialis prevention: an in vivo study. (2010)
[45] Eduardo Cde et al: Prevention of recurrent herpes labialis outbreaks through low-intensity laser therapy: a clinical protocol with 3-year follow-up. (2012)
[46] Hegedus et al: The effect of low-level laser in knee osteoarthritis: a double-blind, randomized, placebo-controlled trial. (2009)
[47] Gur et al: Efficacy of different therapy regimes of low-power laser in painful osteoarthritis of the knee: a double-blind and randomized-controlled trial. (2003)
[48] Stelian et al: Improvement of pain and disability in elderly patients with degenerative osteoarthritis of the knee treated with narrow-band light therapy. (1992)
[49] Alghadir et al: Effect of low-level laser therapy in patients with chronic knee osteoarthritis: a single-blinded randomized clinical study. (2013)
[50] Lam&Cheing: Effects of 904-nm low-level laser therapy in the management of lateral epicondylitis: a randomized controlled trial. (2007)
[51] Ridner et al: A pilot randomized trial evaluating low-level laser therapy as an alternative treatment to manual lymphatic drainage for breast cancer-related lymphedema. (2013)
[52] Ahmed Omar et al: Treatment of post-mastectomy lymphedema with laser therapy: double blind placebo control randomized study. (2011)
[53] Ivandic&Ivandic: Low-level laser therapy improves vision in patients with age-related macular degeneration. (2008)
[54] Leavitt et al: HairMax LaserComb laser phototherapy device in the treatment of male androgenetic alopecia: A randomized, double-blind, sham device-controlled, multicentre trial. (2009)
[55] Lanzafame et al: The growth of human scalp hair mediated by visible red light laser and LED sources in males. (2013)
[56] Shyrygina&Khadzhieva: [Effect of infrared low-intensity laser therapy on orbital blood circulation in children with progressive short sightedness]. (2009)
[57] Landsman et al: Treatment of mild, moderate, and severe onychomycosis using 870- and 930-nm light exposure. (2010)
[58] Melchior Mde et al: Does low intensity laser therapy reduce pain and change orofacial myofunctional conditions? (2013)
[59] Baez&Reilly: The use of light-emitting diode therapy in the treatment of photoaged skin. (2007)
[60] Russell et al: A study to determine the efficacy of combination LED light therapy (633 nm and 830 nm) in facial skin rejuvenation. (2005)
[61] Schubert V: Effects of phototherapy on pressure ulcer healing in elderly patients after a falling trauma. A prospective, randomized, controlled study. (2001)
[62] Hirschl et al: Low level laser therapy in primary Raynaud’s phenomenon–results of a placebo controlled, double blind intervention study. (2004)
[63] Aras&Güngörmüş: The effect of low-level laser therapy on trismus and facial swelling following surgical extraction of a lower third molar. (2009)
[64] Mitchell et al: Restless legs syndrome and near-infrared light: An alternative treatment option. (2011)
[65] Mitchell et al: Comparison of two infrared devices in their effectiveness in reducing symptoms associated with RLS. (2011)
[66] Kubota J: Defocused diode laser therapy (830 nm) in the treatment of unresponsive skin ulcers: a preliminary trial. (2004)
[67] Zhao et al: Red Light and the Sleep Quality and Endurance Performance of Chinese Female Basketball Players (2012)
[68] Barolet&Boucher: LED photoprevention: reduced MED response following multiple LED exposures. (2008)
[69] Simunovic et al: Wound healing of animal and human body sport and traffic accident injuries using low-level laser therapy treatment: a randomized clinical study of seventy-four patients with control group. (2000)
[70] Zhevago&Samoilova: Pro- and Anti-inflammatory Cytokine Content in Human Peripheral Blood after Its Transcutaneous (in Vivo) and Direct (in Vitro) Irradiation with Polychromatic Visible and Infrared Light (2006)
[71] Barulin&Plavskii: Effect of Polarization and Coherence of Optical Radiation on Sturgeon Sperm Motility (2012)
[72] Bashir et al: UVB and proinflammatory cytokines synergistically activate TNF-alpha production in keratinocytes through enhanced gene transcription. (2009)
[73] Stouthard et al: Effects of acute and chronic interleukin-6 administration on thyroid hormone metabolism in humans. (1994)
[74] van der Poll et al: Tumor necrosis factor: a putative mediator of the sick euthyroid syndrome in man. (1990)
[75] Chung et al: The Nuts and Bolts of Low-level Laser (Light) Therapy (2012)
[76] Paradies et al: Cardiolipin-dependent decrease of cytochrome c oxidase activity in heart mitochondria from hypothyroid rats (1997)
[77] Jakovcic et al: Biochemical and stereological analysis of rat liver mitochondria in different thyroid states (1978)

Jagdeo et al: Transcranial red and near infrared light transmission in a cadaveric model. (2012) “These findings indicate that near infrared light can penetrate formalin fixed soft tissue, bone and brain and implicate that benefits observed in clinical studies are potentially related to direct action of near infrared light on neural tissue.”

Rojas et al: Neuroprotective effects of near-infrared light in an in vivo model of mitochondrial optic neuropathy (2008) “superoxide dismutase activities were also increased in NIL-treated subjects in a dose-dependent manner, suggesting an in vivo transcranial effect of NIL.”

Brown GC: Nitric oxide inhibition of cytochrome oxidase and mitochondrial respiration: implications for inflammatory, neurodegenerative and ischaemic pathologies. (1997) “Nitric oxide (NO) at high levels is cytotoxic, and may be involved in a range of inflammatory, neurodegenerative, and cardiovascular/ischaemic pathologies. The mechanism of NO-induced cytotoxicity is unclear. Recently we and others have found that low (nanomolar) levels of NO reversibly inhibit mitochondrial respiration by binding to the oxygen binding site of cytochrome oxidase in competition with oxygen.”

Light promotes regeneration and functional recovery and alters the immune response after spinal cord injury. (2005) “6% of the power of a 150 mW 810 nm laser was transmitted through all of the layers of tissue between the [adult rat] dorsal skin surface and the ventral side of the spinal cord.” “PBM resulted in a significant suppression [...] of IL6 expression at 6 hours post-injury, with a 171-fold decrease in expression of IL6.”

Chung et al: The Nuts and Bolts of Low-level Laser (Light) Therapy (2012) “It was originally believed that the coherence of laser light was crucial to achieve the therapeutic effects of LLLT, but recently this notion has been challenged by the use of LEDs, which emit non-coherent light over a wider range of wavelengths than lasers. It has yet to be determined whether there is a real difference between laser and LED, and if it indeed exists, whether the difference results from the coherence or the monochromaticity of laser light, as opposed to the non-coherence and wider bandwidth of LED light.”
Havelock Ellis: Sexual Education and Nakedness (1909) “The hygienic value of nakedness is indicated by the robust health of the savage throughout the world who go naked. The vigor of the Irish, also, has been connected with the fact that (as Fynes Moryson’s Itinerary shows) both sexes, even among persons of high social class, were accustomed to go naked except for a mantle, especially in more remote parts of the country, until the sevcenteeth century. Wherever primitive races abandon nakedness for clothing, at once the tendency to disease, mortality, and degeneracy notably increases, though it must be remembered that the use of clothing is commonly accompanied by the introduction of other bad habits.“

Wu&Persinger: Increased mobility and stem-cell proliferation rate in Dugesia tigrina induced by 880nm light emitting diode. (2011) “These findings suggest that non-coherent light sources with power-densities about 1000 times lower than contemporary low-power laser settings remain effective in generating photobiostimulation effects and warrants further investigation on stem-cell proliferation induced by near-infrared light emitting diodes.”

Appendix 2: Animal studies (with positive results)

Rats: laryngitisreflux laryngitispalatal mucoperiosteal wound healingbone metabolismperipheral nerve regeneration,acute joint inflammationzymosan-induced arthritistendon healingacute skeletal muscle injuryMetSyn-related kidney injurystreptozotocin-induced diabetic kidneyheart failure-related inflammationcortical metabolic capacity and memory retentiontraumatic brain injuryrheumatoid arthritisacute myocardial infarctionsecond-degree burn healingthird-degree burn healing1 2 3lesions of diabetic retinopathymethanol-induced retinal toxicity 


Extra material



  1. Very good resource here:

    I’ve been using a Bulbrite infrared heat lamp bulb at night and a clear heat lamp bulb during the day (to help with the winter here in New England).

    As far as SAD goes, Sunnex technologies seems to have some interesting things to say about low intensity green light and its physiological effects. If I had the money I’d probably get one of their twin desk lamps. Looks very cool.

    But yeah. This stuff really gets me excited. Light therapy is extremely interesting in its implications not only for seasonal affective disorder but health in general for the entire population. Different wavelengths have different properties and effects on the body and are all worth looking into for better understandings.

    Yeah, though. The infrared heat lamp bulb is pretty badass. I also use an amber LED at night sometimes (from, but I like the idea that the red light has some healing properties in addition to simply not having blue light that keeps you awake at night.

  2. Oh! am I first? Very interesting…thank you :)

  3. First of all, you may want to fix this: ” The subjects weared masks”. Secondly, I bought some red light bulbs at Hobby Lobby for $3 each that I put in lamps around the house that we turn on at night so when we get up in the night we aren’t as disturbed but we can still see where we are going. Seems to be working so far.

    • Thanks, I’ll go correct that. It’s a lot wading through Vladimir’s behemoth posts.

  4. so a fir sauna does or doesn’t help with this? thx in advance

    • Almost all FIR saunas heat the body very unevenly and will put a lot of stress on the autonomic nervous system. Then there is the fumes from the glues and materials, and finally the high levels of EMFs. Lots of sciencey-sounding marketing for this pervades the web, but there doesn’t seem to be anything to back it up.

      Stick to regular saunas or follow the Dr Wilson plans posted above, IMO. Though ignore everything else Wilson says.

  5. Wow, I feel kinda bad for guffawing into my mom’s face when she told me that there was a sauna that uses this “extremely special advanced” technology they have in the sauna room.
    I laughed when she told me, “they use infrared-rays.”
    Because before I just read this article, I had previously thought that infrared-rays had no effects on the body.

    There is an infrared-ray hot sauna room in Fairfax, VA called “The Wellness Spa” if anyone’s interested.

  6. I have built and used an ifrared heat lamp sauna. Basically four 250 watt heat lamp bulbs in a closet. They’re pretty awesome. I liked basking in the red light so much, that I started using the same “lizard lamps” to sun under in my cold bedroom. In fact, I just ordered a smaller lamp @ 75 watts to use in there just because 250 watts is too big of a drain on my solar power system. I’m a real big fan of that light and that particular type of heat. I’ve brainstormed ways to make a sauna using hot coals at the heat source, sort of a natural infrared, without asphixiating from carbon monoxide. That project is on hold, but California Indian sweats in the old days were direct heated like that, unlike the Plains Indian saunas with the hot rocks that most people are familiar with. Anyway, infrared and heat lamps, yes! I find it to be a super relaxing feel good sensation, like being next to a warm body, or laying in the sun. I have The Manual of Sauna Therapy by Wilson. Been a while since I looked at it, but here is a quote I just ran across while trying to find a URL.:

    “Slow Metabolism. Radiation and other toxins often affect the thyroid and adrenal glands resulting in a slow metabolic rate. This condition affects over 90% of adults and causes fatigue, impaired carbohydrate tolerance, food cravings, allergies, obesity, elevated cholesterol, learning disability, chronic infections and other conditions.

    A low body temperature impairs sweating. This hinders elimination and interferes with tissue regeneration. Supporting sluggish thyroid and adrenal glands helps, but is often not enough. By heating the body, saunas activate and enhance many metabolic processes. This is most beneficial for those with sluggish metabolism.”

    Ok, now I’ll go read the article….

  7. Hmm, so counter to the advice on SAD which says blue light is most beneficial. Nervous of my lightbox now!

  8. That must be why sitting close to a fire (in front of a fireplace, for instance) feels so great.

  9. When I had a frozen shoulder, I went to an acupuncturist that used heat lamps (it was winter), which I found to give more pain relief than anything else. I thought these were far infrared, but probably were the osram and phillips heatlamps. Interesting to see why these worked so well.

  10. This probably explains why I tended to avoid Kmart’s “blue light specials” when I was a kid!

  11. I did notice that my SAD symptoms always improved if I went for a walk in the AM, rain or shine, before breakfast (not too intense, just feeling good.) Something about going outside made the difference. I have also noticed that florescent lights make me feel poorly.

  12. Ray Peat has some really weird ideas.

  13. I just wanted to give a shout out to In Light Wellness Systems. They make some really great products, if anyone is interested. They are expensive to buy, but a lot of clinics are now starting to offer them. Personally, I have noticed a big difference, and it happens to feel really good particularly during the cooler months. (No, I don’t work for the company.)

  14. Get outside more (though sunlight doesn’t seem to be a perfect IR light source), go with incandescent over florescent. Any other practical advice from this article? I admit I didn’t read through all of the references.
    BR40 bulb in a clamp light? How close to the skin?

  15. Inspired by peat I made a light setup above my bed last winter: 2 halogen floodlights (400W each) and 2 incandescent bulbs (200W each). I still use it often, It’s great on the dark winter days.

  16. I went to Alibaba to see what I could find in this category, and found a bunch of multi-wavelength LED lamps. None of these cover the whole range of 600 – 1000nm, so I’m not sure if they’d be useful.

    JX-ML100WRI492 690nm,700nm,710nm,720nm
    JX-ML100WII436 730nm,740nm,750nm,760nm
    JX-ML100WUV470 770nm,780nm,790nm,800nm
    JX-ML100WUV417 810nm,830nm,850nm,870nm
    JX-ML100WUV484 880nm,890nm,910nm,940nm

    I guess the ideal would be 690, 740, 850, 940nm?

    • Hi Brock,

      The whole range isn’t important. Certain wavelengths work better than others and this fact is often utilized in laser devices (lasers are monochromatic).

      The optimal wavelengths seem to be 620, 680, 760 and 820 (see Figure 1).

  17. This is being discussed in terms of the light we see over at Seth Robert’s blog. I find the Phillips Hue system ( ) very interesting and could see something like this being the future. The Phillips Hue system allows you to change your lights depending on your needs. I think one day we’ll have lighting systems in houses and TVs that match the f.lux program for computers (F.Lux changes the light emitted from the computer to limit blue light after sundown) – these systems will have stimuating light in the morning and relaxing red/yellow lights at night. People on Seth Rober’s blog report success by using Blue Blocker type sunglasses in their home at night. They seem more focused on limiting blue light than optimizing red but its the flip side of the same coin.

  18. This article reminded me to get my 250 watt heat lamp going again. I have a regular red tinted bulb, which I like for use during the day as well as a 250 watt IR heat only “lizard light” which is very relaxing.

  19. Fascinating.

    Every previous article I’ve read about light in therapy has focused on UV and blue light as a way to enhance circadian rhythms or VitD production — this is the first time I’ve read anything about infrared being the key player (although a web search shows that there’s lots of info out there).

    I wonder if there’s an optimal time-of-day for red light. Reference [67] discusses a study where the subjects were blasted with red light at night, and it enhanced their sleep (although it referenced other studies where insomniacs had even worse sleep after IR irradiation). And bonfires probably put out lots of IR.

    So if we assume nighttime IR is ok, what about day? It doesn’t seem likely that daytime IR is bad, just because there’s lots of it in sunlight.

    So maybe IR is good anytime. That’s probably consistent with IR simply lowering systemic inflammation, as per the Zhevago study.

    I’m definitely intrigued, and might have to pick up some heat lamps.

    Thanks Vladimir!

    • Hi zogby!

      I think that the study mentioned in the study [67] is not a very good proof against red light and NIR :)

      1) The dim-red light group actually got less red light and IR, because they had fewer and less powerful incandescent lights

      “The bright-light box comprised 8 incandescent 75-watt light globes behind a translucent acrylic screen and produced 2500-lux intensity measured at a distance of 70 cm. The dim-light box comprised 4 incandescent 40-watt red light globes behind a translucent acrylic screen, which produced < 100 lux measured at a distance at 70 cm"

      2) The changes in the red light group were quite insignificant… Some of the symptom scores (drowsy, irritable) had actually a decreasing trend.

      The only significant change in dim-light group was that they woke up a little bit earlier. I think one partial reason could be the lack of light (dim conditions) too early in the evening, possibly.

  20. I feel really stupid asking this question but here goes anyway – would a red lampshade or a red painted bulb do anything? Or does it have to be a heat lamp or something special?

    I enjoy the red light from my red lampshade at night ,it feels soothing. And I have always hated fluorescent lighting, it’s always made me feel slightly tired and nauseated. But being a responsible power-saving person I now have them in my home, the compact ones :( silly me.

    Thanks for the great article.

    • As long as it’s a warm incandescent bulb (i.e. halogen, incandescent, or heat lamp), it’ll put out a fair bit of infrared. Take a look at this spectrum chart: The 600-900nm range is what you’d want.

      Fluorescent lights (including CFL) put out very little IR.

      So you don’t even need a special red bulb or shade over an incandescent bulb to get IR — though doing that is probably a good idea at night to avoid the blue portion of the light from screwing up your circadian rhythms. I wouldn’t expect those filters to affect the IR content of the light.

      • Thanks zogby! I’ve been wanting to do this for a while so I got one – 150w IR. The guy said it was 600 – 1000. He said it was a medical lamp.

        • actually he said 700

  21. This is maybe related to the anti inflammatory properties of red light, but you can get a red light device that you put up your nose to treat rhinitis. I didn’t find it very good at the time when I really suffered with allergies, but I’ve noticed my symptoms are better this year since I’ve been eating more. This article has reminded me that lots of people raved about them so I think I will dig them out and stick red light up my nose again!

    • Studies show that lighting up your nose with a red light is also an excellent way of spreading Christmas cheer. I just have one question for you Lindsey. Do you recall the most famous reindeer of all?

  22. Red light is also gluten free.

  23. Any recommendations on products?

      • Are IR heaters basically the same thing as heat lamps? Heat lamps are unpopular where I live, but an IR heater would be really easy to get.

        • There are many types of IR heaters, but a large part of IR heaters seem to use “quartz heat lamps”, which emit IR radiation of 1500-8000nm wavelength. And those wavelengths don’t photodissociate the nitric oxide molecule from cytochrome c oxidase. :)

      • Also, I believe there’s a typo in the post:

        “A review article on this subject states that in central Europe, the amount of IR-A radiation is limited to 20mW/cm2″

        But the source [1] says 200mW/cm2 in summer.

        • It’s not a typo :) The review says it’s 200W/m2.

          200W = 200 000mW
          1 m2 = 10000cm2.

  24. I would be interested to know if fire is helpful in this respect. Perhaps after dark the best thing to do is to light candles. Perhaps not so useful therapeutically as incandescent bulbs, but as a regular, everyday practice it is surely more relaxing than using bulbs. Even better, go camping and make a fire! (And roast some gelatine rich marshmellows ; )

  25. I just started using brooding lights from the farming supply store for my seasonal moodiness. I had been using one 250 watt red heat lamp and switched to two 250 watt brooding lights with excellent results. The cost was only around 20 dollars. I was recommended this by a person who has studied the research of Ray Peat. Hopefully no one is offended by me sharing this info. I think Ray would want as many people possible to know this affordable intervention. I personally wish I had known this 20 years ago!

    • Melissa,
      how exactly are you using them? Just shine them on the whole body, or a particular body part?

      • I’ve used them on a specific body part as well as just sitting next to them while reading. The first day I had them I used them in the kitchen while I cooked. I feel my mood just having them on and sitting close enough to feel their warmth. When my neck or back is sore I can sit with the lights shining directly on the area of discomfort and the pain resolves for me within 5-10 minutes. I’m still experimenting but I think it can’t hurt to expose as much skin as possible. My entire back and neck is uncovered when I’m using it for pain relief. This is probably due to the issue with the cox enzyme mentioned in the article. When I read under the lights I usually wear shorts and a tank top. So far so good and no negative side effects! Hope that helps

    • Hi Melissa, two questions :)

      1) What is the lamp model you are using?

      2) Did you get results with the red heat lamp?

      • I purchased the Westinghouse infared heat lamp 250 watts. The item number listed on the box is 03916. I did feel a benefit from the heat lamp but I probably should have used two. I was only using one. I’ve been reading a lot over the past couple of months to try to find an affordable and effective light intervention. I have no source to site but it seems to me that people are anecdotally doing well with at least 350 watts. I think the only difference in the in the brooding lights and the red heat lamp is that the glass is tinted red. Some say the clear glad lets through more beneficial light. It’s all so interesting and if you consider that they are designed to increase the baby animals health and fertility then it makes since that the same lights would help us too!

  26. Cool post Vladimir, but just to sum up; what should I buy?

    I’m anything but at tech-wiz so you’ve lust me on all the different wave lengths and stuff.
    Could you perhaps put a little check list together for those of us who are clueless?

    • Hi Rasmus,

      I am not sure about this, but I think that even an incandescent bulb or a heat lamp might be effective from a close distance (10-40 centimetres), because they emit the right wavelengths, and the power levels are quite good.

      So far, I have very limited knowledge about the commercial products. Most of them are very expensive. Some of the cheap “Infrared Night Vision” LED products on eBay could be good, but I haven’t heard any personal experiences.

      • I’ve found an infrared heat lamp with the following specs: “permanent phase”(not sure about that), 100 watts.
        Unfortunately it says nothing about wave lengths.
        It’s intended uses are sore muscles and joints, whereas I would like to try it more for general health (mood, sleep, thyroid function, etc.)

        Do you think it would be worth a shot, or should I just get a plain red light bulb and experiment with that?

        • A normal incandescent bulb might be a more reliable source of the needed wavelengths. The bulb doesn’t have to be red color: even normal incandescent bulbs emit the right wavelengths.

          • Interesting, so the important factor is distance (10-40 cm) between the source of light and the body (“inflicted area”)?

            A red/clear incandescent bulb hanging from the ceiling wouldn’t provide much therapy I gather?


            In theory, if the radiation comes from a point source, the intensity decreases 4-fold every time the distance doubles.

            So if we would compare two quite different distances, 10cm and 80cm, there would be a 8-fold difference in distance and 64-fold difference in the intensity of light (if the lamp was a point source).

            If we look at those LLLT studies, the amount of light is often something like 1-50 J/cm2. If you want to get a similar dose from a 150W heat lamp, then you need to spend at least couple of minutes and the distance should be close to 30 centimetres (according to my calculations), to get a few J/cm2. You can increase the distance, but then the treatment time will increase as well.

            But this is just speculation. I hope that more people will try these things out and maybe report whether this will stuff works, and what are the preferred lamps and distances etc…

  27. If you want the very best in LED therapy, you need to buy from one of the oldest and best manufacturers in the United States. This company has been in the business since the 1980’s improving their products for years.

  28. This topic needs a lot of disambiguation. The range of spectral output of various lights that appear red to us is significant. The difference between the mood lighting at your local lounge and the warm glow of the sun is probably significant. People experience obvious benefits immediately with the prior, I would assume not so much with the latter (besides getting in the mood, of course).

    • I dunno. If you find the basic idea that parts of the spectrum have biological effects plausible, I think there’s a clear action to take even without further data, which is to use broad-spectrum lights which more closely mimic the sun’s spectrum (which is > 50% infrared). Perhaps some day the science will be definitive about what types of wavelengths we need, but that’s not today.

      To be sure, there’s no ideal stand-in for the sun, but incandescents come a lot closer than LEDs or CFLs, neither of which have any significant amount of IR:

      I got a couple of heat lamps and am using them when I’m at the computer.

      • This must be why I hate LED lights as much as florescent. Both of them feel very cold to me, and I actually notice I am in a worse mood around them. I am hoping I will be able to continue buying incandescent in the future.

      • However if you wish to have the near infra red (NIR) then chose the Halogen with red filter (720 nm).

        This was how the Meesters’ study referenced at 29 above was done on patients with SAD (not the diet).

        I note the Primal Mark is now pushing Blue in the Morning to boost the Brain; if in addition, you decide to do Red at Night for Depression, it occurs to me you might as well live in your MaryJane growhouse and imbibe oderiferous cannabinoids.


  29. Great article. we use infared lights everyday in Acupuncture though I do not know if they are near-infared.. I need to look into this. I had never heard of the therapeutic effects of near-infared, only far-infared. (far-infared light is used in certain sauna’s with the claim that it mobilizes heavy metals and environmental toxins from the tissue to be excreted in the sweat and urine).

    about 8 years ago I bought this lamp from Gaiam that was said to be used by NASA for the astronauts to help them sleep. The light is blue. I HATED it and it didn’t help me sleep at all, it did the opposite. I don’t understand how they are selling this….

    • I’m not sure what Dr. Peat would say (he often seems to recommend incandescent bulbs or heat lamps).

      I think that the wavelengths are quite good, but on the other hand, the device is quite expensive and the reviewers say that the device is “cheaply constructed”. If the price was $50, I would buy and try it.

  30. Anyone know if there have been any studies showing infrared being beneficial for chronic fatigue. I know that’s what Dr. Wilson says, but I mean other than that.

    When my dad was recovering from open heart surgery they used a lamp on his wound. At home he used a regular desk lamp with an incandescent bulb which just concentrated warmth right on the spot. Don’t know if helped the wound heal faster but I do know it was the recommendation of the surgeon and not something picked up out of the ether. This was in the mid 80s.

    • Everything that happened in the mid 80’s is superior to today. The 80’s were the peak of human civilization. It’s been all downhill since then. Hey Nipper!

  31. Vlad, is it possible to just buy infrared light bulbs and use them in your ceiling? Or do the bulbs need to get close to your skin to have a therapeutic effect? And what do you think about full spectrum light bulbs that mimic the sun’s wavelength?

    • Incandescent lamps have better spectrum than “infrared heat lamps”. Nowadays the biggest problem might be that we are shifting to energy-saving bulbs with no near-infrared.

      I think that full-spectrum lamps don’t often have any near-infrared. They are visually good but incandescent lamps or halogen lamps would possibly be healthier.

      I don’t know how much the distance from the skin matters. And the sad thing is that nobody actually knows much about those things.

      The best bet might be to get some short distance exposure (less than 50cm) for at least 5 minutes, a few times every week. But I really don’t know.

      • Cool, full spectrum light bulbs are supposed to help balance the serotonin, melatonin cycle in the same way the sun does…reputedly.



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