We performed a thorough review of the scientific literature stored online as it relates to light therapy at the wavelengths of 660nm (red) and 850nm (infrared). It is important to understand that there are several terms used in the publications which should be explored. Included here are all 96 of the research articles we reviewed.
Our Research Methods
Light therapy, low level laser therapy (LLLT), low level light therapy (LLLT), light emitting diode therapy (LED therapy or LEDT), photobiomodulation, phototherapy, and red light treatment or infrared light treatment are all search terms we came across in our search. For the remainder of the article, we will refer to all of these terms as red light therapy, assuming the wavelengths fall within the relevant ranges.
The important content that we sought was wavelengths of light used and the characteristics of the mechanisms of action described in the publications. Generally, we accepted anything between 610nm and 680nm for red light and between 810nm and 880nm for infrared light as relevant to this discussion. In addition, we sought the primary mechanisms of action indicating similar function such as nitric oxide production, ATP, cytochrome c oxidase interaction, increased blood supply, interaction with neuronal cells, and several other criteria.
The reason for this is that although not all the papers directly discuss the impact of our wavelengths in question, it is understood that the cellular activity of absorption occurs along a spectral curve, peaking at different wavelengths and causing differing levels of interaction and benefits derived [1]. In addition, LEDs provide a somewhat wider range of wavelength than those advertised, which is the peak wavelength. But they also use wavelengths +/-5 or 10nm on either side of the peak.
With that being said, we also discovered in our research that the same effects occurred, at least for the topics we are discussing here, across the wavelengths that we accepted as relevant. We did not deviate from the commonly reported benefits of red light therapy and reported only what we found to be consistent effects in the literature.
REFERENCES
HOW DOES IT WORK?
[1] Low-level light therapy of the eye and brain - PMC (nih.gov) - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5436183/
[2] Investigating the effects of low intensity visible light on human keratinocytes using a customized LED exposure system - https://pubmed.ncbi.nlm.nih.gov/36344673/
[3] Photobiomodulation enhancement of cell proliferation at 660 nm does not require cytochrome c oxidase - https://pubmed.ncbi.nlm.nih.gov/30927704/
[4] Low-level laser (light) therapy (LLLT) in skin: stimulating, healing, restoring - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4126803/
[5] Proposed Mechanisms of Photobiomodulation or Low-Level Light Therapy | IEEE Journals & Magazine | IEEE Xplore - https://ieeexplore.ieee.org/abstract/document/7488285
[6] Effect of Red-to-Near Infrared Light on the Reaction of Isolated Cytochrome c Oxidase with Cytochrome c - https://pubmed.ncbi.nlm.nih.gov/27111566/
[7] Photobiomodulation Response From 660 nm is Different and More Durable Than That From 980 nm - https://pubmed.ncbi.nlm.nih.gov/33998008/
[8] Investigating the effects of low intensity visible light on human keratinocytes using a customized LED exposure system - https://pubmed.ncbi.nlm.nih.gov/36344673/
[9] A study to determine the efficacy of combination LED light therapy (633 nm and 830 nm) in facial skin rejuvenation - https://pubmed.ncbi.nlm.nih.gov/16414908/
[10] Phototherapy promotes healing of chronic diabetic leg ulcers that failed to respond to other therapies - https://onlinelibrary.wiley.com/doi/10.1002/lsm.20789
[11] GaAlAs (830 nm) low-level laser enhances peripheral endogenous opioid analgesia in rats - https://pubmed.ncbi.nlm.nih.gov/18081143/
[12] R&D report: the benefits of phototherapy: the horizon infrared and red light therapy unit delivers 800 mW of infrared (880 nm) and red (660 nm) light with 36 infrared LEDs and seven visible red LEDs. - link.gale.com/apps/doc/A172598200/HRCA?u=nysl_oweb&sid=googleScholar&xid=a2285fac
[13] What Lies at the Heart of Photobiomodulation: Light, Cytochrome C Oxidase, and Nitric Oxide-Review of the Evidence - https://pubmed.ncbi.nlm.nih.gov/32716711/
[14] Specific helium-neon laser sensitivity of the purified cytochrome c oxidase - https://pubmed.ncbi.nlm.nih.gov/10902741/
[15] Nitric oxide and cytochrome oxidase: substrate, inhibitor or effector? - https://pubmed.ncbi.nlm.nih.gov/11796222/
[16] Cytochrome c oxidase structures suggest a four-state stochastic pump mechanism - PubMed (nih.gov) - https://pubmed.ncbi.nlm.nih.gov/30775748/
[17] Nitric oxide and cellular respiration - PubMed (nih.gov) - https://pubmed.ncbi.nlm.nih.gov/11212305/
[18] Physiology, Adenosine Triphosphate - StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK553175/
[21] In vitro observations on the influence of copper peptide aids for the LED photoirradiation of fibroblast collagen synthesis - https://pubmed.ncbi.nlm.nih.gov/17603859/
IMPROVE COGNITIVE FUNCTION
[19] Pulsed Transcranial Red/Near-Infrared Light Therapy Using Light-Emitting Diodes Improves Cerebral Blood Flow and Cognitive Function in Veterans with Chronic Traumatic Brain Injury: A Case Series - https://www.liebertpub.com/doi/full/10.1089/pho.2018.4489
[20] Light-emitting diode treatment reverses the effect of TTX on cytochrome oxidase in neurons - PubMed (nih.gov) - https://pubmed.ncbi.nlm.nih.gov/11568632/
[22] Transcranial, Red/Near-Infrared Light-Emitting Diode Therapy to Improve Cognition in Chronic Traumatic Brain Injury - https://www.liebertpub.com/doi/abs/10.1089/pho.2015.4037
[23] Pulsed Transcranial Red/Near-Infrared Light Therapy Using Light-Emitting Diodes Improves Cerebral Blood Flow and Cognitive Function in Veterans with Chronic Traumatic Brain Injury: A Case Series - https://www.liebertpub.com/doi/full/10.1089/pho.2018.4489
[24] Significant Improvements in Cognitive Performance Post-Transcranial, Red/Near-Infrared Light-Emitting Diode Treatments in Chronic, Mild Traumatic Brain Injury: Open-Protocol Study - https://www.liebertpub.com/doi/abs/10.1089/neu.2013.3244
[25] Rapid Reversal of Cognitive Decline, Olfactory Dysfunction, and Quality of Life Using Multi-Modality Photobiomodulation Therapy: Case Report) - https://www.liebertpub.com/doi/abs/10.1089/photob.2018.4569
[26] Can transcranial photobiomodulation improve cognitive function? A systematic review of human studies - ScienceDirect - https://www.sciencedirect.com/science/article/pii/S1568163722002288
[27] Transcranial infrared laser stimulation produces beneficial cognitive and emotional effects in humans - ScienceDirect - https://www.sciencedirect.com/science/article/abs/pii/S0306452212011268
[28] Frontiers | Turning On Lights to Stop Neurodegeneration: The Potential of Near Infrared Light Therapy in Alzheimer's and Parkinson's Disease - https://www.frontiersin.org/articles/10.3389/fnins.2015.00500/full
RELEASE OF BETA ENDORPHINS
[29] Peripheral beta-endorphin and pain modulation. - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2161980/
[30] Blue light (λ=453 nm) nitric oxide dependently induces β-endorphin production of human skin keratinocytes in-vitro and increases systemic β-endorphin levels in humans in-vivo - https://www.sciencedirect.com/science/article/abs/pii/S089158491931158X
[31] Roles of β-Endorphin in Stress, Behavior, Neuroinflammation, and Brain Energy Metabolism - PMC (nih.gov) - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7796446/
[32] The role of beta-endorphin in the pathophysiology of major depression - https://pubmed.ncbi.nlm.nih.gov/19647870/
[33] The β-Endorphin Role in Stress-Related Psychiatric Disorders - https://www.ingentaconnect.com/content/ben/cdt/2009/00000010/00000011/art00007
[34] Opioids and anxiety - https://journals.sagepub.com/doi/abs/10.1177/0269881110367726
[35] PLASMA ACTH AND β-ENDORPHIN LEVELS IN RESPONSE TO LOW LEVEL LASER THERAPY (LLLT) FOR MYOFASCIAL TRIGGER POINTS - https://www.jstage.jst.go.jp/article/islsm/6/3/6_94-OR-07/_article/-char/ja/
[36] GaAlAs (830 nm) low-level laser enhances peripheral endogenous opioid analgesia in rats - PubMed (nih.gov) - https://pubmed.ncbi.nlm.nih.gov/18081143/
[37] Pre-Irradiation of Blood by Gallium Aluminum Arsenide (830 n... : Anesthesia & Analgesia - https://journals.lww.com/anesthesia-analgesia/fulltext/2008/09000/Pre_Irradiation_of_Blood_by_Gallium_Aluminum.57.aspx
[38] Blue light (λ=453 nm) nitric oxide dependently induces β-endorphin production of human skin keratinocytes in-vitro and increases systemic β-endorphin levels in humans in-vivo - https://www.sciencedirect.com/science/article/abs/pii/S089158491931158X
IMPROVED SLEEP
[39] Red Light and the Sleep Quality and Endurance Performance of Chinese Female Basketball Players - https://meridian.allenpress.com/jat/article/47/6/673/111318/Red-Light-and-the-Sleep-Quality-and-Endurance
[40] Significant Improvements in Cognitive Performance Post-Transcranial, Red/Near-Infrared Light-Emitting Diode Treatments in Chronic, Mild Traumatic Brain Injury: Open-Protocol Study - https://www.liebertpub.com/doi/10.1089/neu.2013.3244
[41] Melatonin as a principal component of red light therapy - https://pubmed.ncbi.nlm.nih.gov/17321060/
[42] Role of Melatonin in the Regulation of Human Circadian Rhythms and Sleep - https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1365-2826.2003.00989.x
IMPROVED MOOD
[31] Roles of β-Endorphin in Stress, Behavior, Neuroinflammation, and Brain Energy Metabolism - PMC (nih.gov) - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7796446/
[32] The role of beta-endorphin in the pathophysiology of major depression - https://pubmed.ncbi.nlm.nih.gov/19647870/
[34] Opioids and anxiety - https://journals.sagepub.com/doi/abs/10.1177/0269881110367726
[43] The effects of sleep deprivation on mood. - https://psycnet.apa.org/record/1978-20357-001
[44] Total sleep deprivation, chronic sleep restriction and sleep disruption - https://www.sciencedirect.com/science/article/abs/pii/B9780444537027000063
[45] The effects of chronic sleep reduction on the performance of cognitive tasks sensitive to sleep deprivation - https://onlinelibrary.wiley.com/doi/abs/10.1002/acp.2350090103
[46] Sleep deprivation leads to mood deficits in healthy adolescents - https://www.sciencedirect.com/science/article/abs/pii/S138994571500698X
INFLAMMATION
[47] Inflammation Mediates Body Weight and Ageing Effects on Psychomotor Slowing | Scientific Reports (nature.com) - https://www.nature.com/articles/s41598-019-52062-3
[48] Radiation, inflammation and the immune response in cancer - https://link.springer.com/article/10.1007/s00335-018-9777-0
[49] Markers of inflammation and their clinical significance - ScienceDirect - https://www.sciencedirect.com/science/article/abs/pii/S1567568805000061
[50] Inflamed moods: A review of the interactions between inflammation and mood disorders - ScienceDirect - https://www.sciencedirect.com/science/article/abs/pii/S0278584614000141
[51] Low level light effects on inflammatory cytokine production by rheumatoid arthritis synoviocytes - https://onlinelibrary.wiley.com/doi/abs/10.1002/lsm.20766
[52] Dual Effect of low‐level laser therapy (LLLT) on the acute lung inflammation induced by intestinal ischemia and reperfusion: Action on anti‐ and pro‐inflammatory cytokines - https://onlinelibrary.wiley.com/doi/abs/10.1002/lsm.21053
[53] Macrophages Modulated by Red/NIR Light: Phagocytosis, Cytokines, Mitochondrial Activity, Ca2+ Influx, Membrane Depolarization and Viability - https://onlinelibrary.wiley.com/doi/abs/10.1111/php.13526
[54] LED therapy or cryotherapy between exercise intervals in Wistar rats: anti-inflammatory and ergogenic effects - https://link.springer.com/article/10.1007/s10103-013-1371-9
PAIN
[29] Peripheral beta-endorphin and pain modulation. - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2161980/
[35] PLASMA ACTH AND β-ENDORPHIN LEVELS IN RESPONSE TO LOW LEVEL LASER THERAPY (LLLT) FOR MYOFASCIAL TRIGGER POINTS - https://www.jstage.jst.go.jp/article/islsm/6/3/6_94-OR-07/_article/-char/ja/
[55] Understanding Endorphins and Their Importance in Pain Management - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3104618/
[56] Cytokines, Inflammation and Pain - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2785020/
[57] Light-emitting diode phototherapy: pain relief and underlying mechanisms - https://pubmed.ncbi.nlm.nih.gov/35404002/
[58] Review of Literature on Low-level Laser Therapy Benefits for Nonpharmacological Pain Control in Chronic Pain and Osteoarthritis - https://pubmed.ncbi.nlm.nih.gov/28987080/
[59] Low-intensity LASER and LED (photobiomodulation therapy) for pain control of the most common musculoskeletal conditions - https://pubmed.ncbi.nlm.nih.gov/34913330/
[60] The Use of Low Level Laser Therapy (LLLT) For Musculoskeletal Pain - https://pubmed.ncbi.nlm.nih.gov/26858986/
[61] Postendodontic treatment pain management with low-level laser therapy - https://jdentlasers.org/article.asp?issn=2321-1385;year=2014;volume=8;issue=2;spage=60;epage=63;aulast=Pawar
IMPROVED POST EXERCISE & MUSCULAR INJURY RECOVERY
[62] Effects of light emitting diode (LED) therapy and cold water immersion therapy on exercise-induced muscle damage in rats - https://pubmed.ncbi.nlm.nih.gov/22223060/
[63] LED therapy or cryotherapy between exercise intervals in Wistar rats: anti-inflammatory and ergogenic effects - https://link.springer.com/article/10.1007/s10103-013-1371-9
[64] Effect of cluster multi‐diode light emitting diode therapy (LEDT) on exercise‐induced skeletal muscle fatigue and skeletal muscle recovery in humans - https://onlinelibrary.wiley.com/doi/abs/10.1002/lsm.20810
[65] Comparison between cold water immersion therapy (CWIT) and light emitting diode therapy (LEDT) in short-term skeletal muscle recovery after high-intensity exercise in athletes--preliminary results - https://pubmed.ncbi.nlm.nih.gov/21088862/
[66] Does photobiomodulation therapy is better than cryotherapy in muscle recovery after a high-intensity exercise? A randomized, double-blind, placebo-controlled clinical trial - https://link.springer.com/article/10.1007/s10103-016-2139-9
[67] Phototherapy in skeletal muscle performance and recovery after exercise: effect of combination of super-pulsed laser and light-emitting diodes - https://link.springer.com/article/10.1007/s10103-014-1611-7
[69] Photobiomodulation in human muscle tissue: an advantage in sports performance? - https://onlinelibrary.wiley.com/doi/abs/10.1002/jbio.201600176
EHANCED ATHLETIC PERFORMANCE
[63] LED therapy or cryotherapy between exercise intervals in Wistar rats: anti-inflammatory and ergogenic effects - https://link.springer.com/article/10.1007/s10103-013-1371-9
[64] Effect of cluster multi‐diode light emitting diode therapy (LEDT) on exercise‐induced skeletal muscle fatigue and skeletal muscle recovery in humans - https://onlinelibrary.wiley.com/doi/abs/10.1002/lsm.20810
[67] Phototherapy in skeletal muscle performance and recovery after exercise: effect of combination of super-pulsed laser and light-emitting diodes - https://link.springer.com/article/10.1007/s10103-014-1611-7
[68] Low-level laser (light) therapy (LLLT) on muscle tissue: performance, fatigue and repair benefited by the power of light - https://www.degruyter.com/document/doi/10.1515/plm-2012-0032/html
[69] Photobiomodulation in human muscle tissue: an advantage in sports performance? - https://onlinelibrary.wiley.com/doi/abs/10.1002/jbio.201600176
IMPROVED SKIN HEALTH
[70] Photobiomodulation: The Clinical Applications of Low-Level Light Therapy | Aesthetic Surgery Journal - https://academic.oup.com/asj/article/41/6/723/6104785
ACNE
[4] Low-level laser (light) therapy (LLLT) in skin: stimulating, healing, restoring - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4126803/
[71] A global perspective on the epidemiology of acne - PubMed (nih.gov) - https://pubmed.ncbi.nlm.nih.gov/25597339/
[72] A Qualitative Investigation of the Impact of Acne on Health-Related Quality of Life (HRQL): Development of a Conceptual Model - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5825329/
[73] Blue and red light combination LED phototherapy for acne vulgaris in patients with skin phototype IV - https://pubmed.ncbi.nlm.nih.gov/17111415/
[74] Phototherapy with blue (415 nm) and red (660 nm) light in the treatment of acne vulgaris - Wiley Online Library - https://onlinelibrary.wiley.com/doi/full/10.1046/j.1365-2133.2000.03481.x
[75] Comparison of Red and Infrared Low-level Laser Therapy in the Treatment of Acne Vulgaris - https://pubmed.ncbi.nlm.nih.gov/22615511/
[76] Low‐level red LED light inhibits hyperkeratinization and inflammation induced by unsaturated fatty acid in an in vitro model mimicking acne - https://onlinelibrary.wiley.com/doi/abs/10.1002/lsm.22747
[77] Red Light Phototherapy Alone Is Effective for Acne Vulgaris: Randomized, Single‐Blinded Clinical Trial - https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1524-4725.2007.33258.x
COLLAGEN / AGING / WRINKLES
[78] Decreased Collagen Production in Chronologically Aged Skin: Roles of Age-Dependent Alteration in Fibroblast Function and Defective Mechanical Stimulation - https://www.sciencedirect.com/science/article/pii/S0002944010622055
[79] Effects of a nutritional supplement containing collagen peptides on skin elasticity, hydration and wrinkles - https://www.jmnn.org/article.asp?aulast=Borumand&epage=53&issn=2278-1870&issue=1&spage=47&volume=4&year=2015
[80] Collagen induction therapy for the treatment of upper lip wrinkles - https://www.tandfonline.com/doi/abs/10.3109/09546634.2010.544709
[81] Oral Intake of Specific Bioactive Collagen Peptides Reduces Skin Wrinkles and Increases Dermal Matrix Synthesis - https://www.karger.com/Article/Abstract/355523
[82] In vitro observations on the influence of copper peptide aids for the LED photoirradiation of fibroblast collagen synthesis - https://pubmed.ncbi.nlm.nih.gov/17603859/
[83] Regulation of skin collagen metabolism in vitro using a pulsed 660 nm LED light source: clinical correlation with a single-blinded study - https://pubmed.ncbi.nlm.nih.gov/19587693/
[84] A Controlled Trial to Determine the Efficacy of Red and Near-Infrared Light Treatment in Patient Satisfaction, Reduction of Fine Lines, Wrinkles, Skin Roughness, and Intradermal Collagen Density Increase - https://www.liebertpub.com/doi/full/10.1089/pho.2013.3616
[85] A study to determine the efficacy of combination LED light therapy (633 nm and 830 nm) in facial skin rejuvenation - https://pubmed.ncbi.nlm.nih.gov/16414908/
SCARS
[86] Prophylactic low‐level light therapy for the treatment of hypertrophic scars and keloids: A case series - https://onlinelibrary.wiley.com/doi/abs/10.1002/lsm.20952
[87] Efficacy of low-level laser therapy on scar tissue: Journal of Cosmetic and Laser Therapy: Vol 15, No 3 (tandfonline.com) - https://www.tandfonline.com/doi/abs/10.3109/14764172.2013.769272
[88] Prevention of Thyroidectomy Scars in Asian Adults With Low-Level Light Therapy - https://journals.lww.com/dermatologicsurgery/Abstract/2016/04000/Prevention_of_Thyroidectomy_Scars_in_Asian_Adults.14.aspx
[89] Increased epidermal thickness and abnormal epidermal differentiation in keloid scars - https://onlinelibrary.wiley.com/doi/10.1111/bjd.14844
WOUND REPAIR
[90] Phototherapy promotes healing of chronic diabetic leg ulcers that failed to respond to other therapies - https://onlinelibrary.wiley.com/doi/10.1002/lsm.20789
[91] Effectiveness of laser photobiomodulation at 660 or 780 nanometers on the repair of third-degree burns in diabetic rats - https://pubmed.ncbi.nlm.nih.gov/18248161/
[92] Effect of red and near-infrared wavelengths on low-level laser (light) therapy-induced healing of partial-thickness dermal abrasion in mice - https://pubmed.ncbi.nlm.nih.gov/23619627/
[93] Effects of low-power light therapy on wound healing: LASER x LED Effects of low-power light therapy on wound healing: LASER x LED - https://www.scielo.br/j/abd/a/pRwVq9Z7WyJrD6ZB8zscpTG/abstract/?lang=en
[94] Investigating the effects of low intensity visible light on human keratinocytes using a customized LED exposure system - https://pubmed.ncbi.nlm.nih.gov/36344673/
[95] Low-energy helium-neon laser irradiation stimulates interleukin-1 alpha and interleukin-8 release from cultured human keratinocytes - https://pubmed.ncbi.nlm.nih.gov/8823366/
[96] The Immune Functions of Keratinocytes in Skin Wound Healing - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7699912/
