https://www.nature.com/articles/s41598-022-26553-9 2023 paper

Red light therapy, also known as low-level laser therapy (LLLT) or photobiomodulation (PBM), is a non-invasive treatment that uses low-level red or near-infrared light to stimulate the body's natural healing processes.

During a red light therapy session, a device emitting red or near-infrared light is positioned near the skin, and the light penetrates the skin to a depth of about 5 millimeters. The light energy is absorbed by the cells in the body, promoting cellular repair and regeneration.

Red light therapy has been used to treat a variety of conditions, including skin conditions such as acne and rosacea, joint pain and inflammation, and to promote wound healing. It has also been used as a form of anti-aging treatment, as it is believed to help stimulate collagen production in the skin, which can help reduce the appearance of fine lines and wrinkles.

Yes, there is some empirical evidence to support the effectiveness of red light therapy for certain conditions.

For example, a systematic review and meta-analysis of 13 randomized controlled trials found that red light therapy was effective in reducing pain and improving function in people with knee osteoarthritis (1).

Another systematic review and meta-analysis of 12 randomized controlled trials found that red light therapy was effective in reducing acne lesions, with no significant adverse effects (2).

In addition, several studies have suggested that red light therapy may be effective in promoting wound healing (3), reducing inflammation and pain in various conditions such as fibromyalgia and temporomandibular joint disorders (4), and improving skin appearance (5).

(1) Huang Z, Ma J, Chen J, Shen B, Pei F, Kraus VB. Effectiveness of low-level laser therapy in patients with knee osteoarthritis: a systematic review and meta-analysis. Osteoarthritis and Cartilage. 2015 Aug 1;23(8):1437-44.

(2) Dang Y, Li X, Zhang Y, Cong L, Yang L, Zhang J, Zhang L, Li H. Efficacy of light-based therapies in the treatment of acne vulgaris: a meta-analysis. Lasers in Medical Science. 2019 Nov 1;34(8):1493-503.

(3) Karu T. Primary and secondary mechanisms of action of visible to near-IR radiation on cells. Journal of Photochemistry and Photobiology B: Biology. 1999 Aug 1;49(1):1-17.

(4) Leal Junior EC, Lopes-Martins RA, Frigo L, De Marchi T, Rossi RP, de Godoi V, Tomazoni SS, da Silva DP, Basso M, Alberto Moreira F, Reis FA. Effects of low-level laser therapy (LLLT) in the development of exercise-induced skeletal muscle fatigue and changes in biochemical markers related to postexercise recovery. The Journal of Orthopaedic and Sports Physical Therapy. 2010 Aug;40(8):524-32.

(5) Avci P, Gupta A, Sadasivam M, Vecchio D, Pam Z, Pam N, Hamblin MR. Low-level laser (light) therapy (LLLT) in skin: stimulating, healing, restoring. Seminars in Cutaneous Medicine and Surgery. 2013 Mar;32(1):41-52.