Although red light therapy (RLT), or in other words photobiomodulation (PBM), is a well-studied and documented topic (there are over 121,000 studies on it on PubMed.gov), it has only recently achieved noteworthy status thanks to today’s technological advances.
PBM uses a low-level laser that irradiates tissue with red and near-infrared (NIR) light. The light penetrates deep into the tissue and affects the mitochondria there, increasing the production of adenosine triphosphate (ATP), whose role is to provide energy for numerous biochemical reactions. As a result, it stimulates faster production of collagen, vascular structures, DNA, RNA, and other materials necessary for various processes in the body.
To all this, phototherapy uses non-thermal, non-invasive light to achieve a therapeutic result. This means that it is a painless, drug-free, natural procedure, after which no recovery time is required. Therefore, it has no serious consequences or contraindications.
Due to its effectiveness and safety, photobiomodulation is actively used for various medical and cosmetic purposes.
Noticeable results of PBM efficacy achieved concerning:
- reduction of fine lines, wrinkles, and increased collagen density in the intradermal tissue 
- treatment of inflammatory diseases, especially acne 
- wound healing and scar prevention 
- stimulation of hair growth in both men and women [4, 5]
- aid in weight loss in overweight people [6, 7]
- reducing the appearance of cellulite [8, 9]
- оrelief of pain (lower back pain [10, 11], neuropathy [12, 15, 20], osteoarthritis [13, 14] etc.)
- improvement of sleep and depressed mood [16, 17, 18, 19]
The main application of photobiomodulation is tissue repair, pain, and inflammation relief.
However, it is important to understand that red light therapy is not a one-time treatment. The treatment period is prescribed individually for each case. In some cases, treatment lasts one to three months with several weekly sessions (e.g., for temporary pain relief, wound healing, or seasonal mood disorders), and in some cases, continuous maintenance therapy may be needed to maintain results (e.g., to combat wrinkles or chronic pain).
 Goldberg DJ, Russell BA. Combination blue (415 nm) and red (633 nm) LED phototherapy in the treatment of mild to severe acne vulgaris. J Cosmet Laser Ther. 2006 Jun;8(2):71-5. doi: 10.1080/14764170600735912. PMID: 16766484
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 Saltmarche AE, Naeser MA, Ho KF, Hamblin MR, Lim L. Significant Improvement in Cognition in Mild to Moderately Severe Dementia Cases Treated with Transcranial Plus Intranasal Photobiomodulation: Case Series Report. Photomed Laser Surg. 2017 Aug;35(8):432-441. doi: 10.1089/pho.2016.4227. Epub 2017 Feb 10. PMID: 28186867; PMCID: PMC5568598.
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 Reeves GM, Nijjar GV, Langenberg P, Johnson MA, Khabazghazvini B, Sleemi A, Vaswani D, Lapidus M, Manalai P, Tariq M, Acharya M, Cabassa J, Snitker S, Postolache TT. Improvement in depression scores after 1 hour of light therapy treatment in patients with seasonal affective disorder. J Nerv Ment Dis. 2012 Jan;200(1):51-5. doi: 10.1097/NMD.0b013e31823e56ca. PMID: 22210362; PMCID: PMC5336550.
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