Low-Level Laser Therapy for Hair Loss: What You Need to Know

Low-Level Laser Therapy for Hair Loss: What You Need to Know

Red and near-infrared laser lights have been used for a long time for tissue repair and regeneration. But after the discovery of lasers in 1960, a new therapy for stimulating cellular activity was introduced, called low-level laser therapy (LLLT)[1]. Since then, various industries took advantage of laser devices to treat different medical conditions, such as wound healing, stroke recovery, nerve regeneration, and joint pain relief[2]. Today, one of the most successful applications of LLLT is the stimulation of hair growth in the scalp’s balding areas[3].

Actually, the name of low-level laser therapy is more commercially used, but international agreement recognized the term “photobiomodulation, PBM” more relevant[4]. PBM has replaced LLLT mainly for two reasons. First, because it was agreed that the term “low” had no concrete meaning. Then, after finding out that light-emitting diodes (LEDs) could perform as well as lasers, the word “laser” was no longer appropriate.

LLLT devices

LLLT devices have been used for years in the treatment of hair loss. They can be used at home without medical attention. In 2007 and 2011, the FDA approved the first LLLT device as a safe treatment for male and female pattern hair loss. Currently, you can find LLLT devices in many forms, including caps, combs, and headbands. Mostly, they use low power (5 mW) red laser diodes, and recently some contain LEDs in addition to lasers. The red wavelengths are usually effective between 630 nm and 660 nm. 

The device’s total number of laser diodes determines the total power administered to the scalp. This only affects the time required to obtain the desired results and the coverage rate. More laser diodes provide better scalp coverage, but it does not make the hair grow faster[5].

How LLLT stimulates hair growth

When the scalp tissues absorb the lights, it induces physiological reactions that affect the hair follicles, stimulating hair growth.

Low-level laser therapy for hair growth

Hair follicles (HF) undergo repetitive cycles of three stages. Anagen is the active stage, during which the hair grows, lasts between 2-6 years. Catagen is the transitional phase, during which the hair moves from anagen to telogen stage, lasts 1-2 weeks. Telogen is the resting stage, during which the hair follicles remain inactive, lasts up to 3 months

Hair loss (or alopecia) mostly develops when the hair growth cycle is disrupted. Two main forms of alopecia require treatments; androgenetic alopecia (AGA) and alopecia areata (AA).

AGA is the most common form of hair loss that affects the majority of men as they age and is also called male pattern baldness. But women can also suffer from AGA. AGA is caused by genetic and hormonal factors, as well as an irregularity between two androgen steroids, testosterone, and dihydrotestosterone (DHT). High levels of DHT can affect hair follicles to stay in the resting phase for longer, decreasing the hair production rate. This can also cause hair to grow thinner and smaller.

AA is an auto-immune disease and develops when the body attacks its own hair follicles, more precisely when T-cells attack the HF. AA can begin at any age. Most people develop AA during childhood or their teenage years, and about half of them see their hair regrow within 12 months without treatment[6].

LLLT in treating androgenic alopecia

The use of low-level laser therapy for AGA shows to move more hair in the anagen phase, increase the anagen phase’s duration, increase the reproduction rate of inactive hair follicles, and prevent premature catagen development[7]. LLLT is also assumed to modulate 5-α reductase expression responsible for converting testosterone into DHT. Thus LLLT decreases DHT production, which has significant roles in hair follicle growth.

Matt Leavitt, and other researchers, used the first approved LLLT device, HairMax Laser Comb (655 nm), on a 26-week trial with 110 males patients suffering from AGA[8]. Results show an increase in hair density for the patients receiving LLLT, while the non-LLLT part presents decreased hair density. The study suggests that LLLT is an effective, well-tolerated, and safe therapy for AGA treatment in men.

Another study reported improvements in hair regrowth in both men and women using the HairMax device[9]. The LLLT increased the hair counts by 51% in patients suffering from AGA.

LLLT in treating alopecia areata

LLLT has also been demonstrated to modulate inflammatory processes. Inflammatory infiltrates highly disruptive the hair follicle biology. A highly inflammatory environment encourages T-cell attack on the HF, while a less inflammatory environment is more healthy for the HF.

Research found that LLLT can treat multiple forms of AA[10]. The authors used a device operating with infrared wavelengths (600–1,600nm) on 15 patients over 18 years, diagnosed with alopecia areata. The patients were irradiated intermittently for 3 minutes once every week or every two weeks. The hair regrowth occurred 1.6 months earlier than the nonirradiated areas in 46% of patients. The hair density and length were the same, suggesting that LLLT only accelerates the hair regrowth process in AA patients. 

Effectiveness & risks of LLLT

An article published by Lasers Surg Med summarized the results of 8 clinical trials for LLLT found on PubMed and Google Scholar[11]. Most studies investigating the effects of LLLT on hair growth have used wavelengths that range from 635 to 650 nm. All clinical trials concluded that LLLT is an effective and convenient solution for the treatment of alopecia. No serious adverse reactions were detected.


  1. Schindl A, Schindl M, Pernerstorfer-Schön H, Schindl L. Low-intensity laser therapy: a review. J Investig Med. 2000 Sep;48(5):312-26. PMID: 10979236.
  2. Bjordal JM, Couppé C, Chow RT, Tunér J, Ljunggren EA. A systematic review of low-level laser therapy with location-specific doses for pain from chronic joint disorders. Aust J Physiother. 2003;49(2):107-16. DOI: 10.1016/s0004-9514(14)60127-6. PMID: 12775206.
  3. Metelitsa AI, Green JB. Home-use laser and light devices for the skin: an update. Semin Cutan Med Surg. 2011 Sep;30(3):144-7. doi: 10.1016/j.sder.2011.05.005. PMID: 21925367.
  4. Anders JJ, Lanzafame RJ, Arany PR. Low-level light/laser therapy versus photobiomodulation therapy. Photomed Laser Surg. 2015 Apr;33(4):183-4. doi: 10.1089/pho.2015.9848. PMID: 25844681; PMCID: PMC4390214.
  5. https://bbbprograms.org/archive/nad-recommends-capillus-discontinue-certain-claims-for-its-laser-device-including-clinically-proven-and-physician-recommended-claims/
  6. https://www.aad.org/public/diseases/hair-loss/types/alopecia
  7. Leavitt M, Charles G, Heyman E, Michaels D. HairMax LaserComb laser phototherapy device in the treatment of male androgenetic alopecia: A randomized, double-blind, sham device-controlled, multicentre trial. Clin Drug Investig. 2009;29(5):283-92. doi: 10.2165/00044011-200929050-00001. PMID: 19366270.
  8. Leavitt M, Charles G, Heyman E, Michaels D. HairMax LaserComb laser phototherapy device in the treatment of male androgenetic alopecia: A randomized, double-blind, sham device-controlled, multicentre trial. Clin Drug Investig. 2009;29(5):283-92. doi: 10.2165/00044011-200929050-00001. PMID: 19366270.
  9. Friedman S, Schnoor P. Novel Approach to Treating Androgenetic Alopecia in Females With Photobiomodulation (Low-Level Laser Therapy). Dermatol Surg. 2017 Jun;43(6):856-867. doi: 10.1097/DSS.0000000000001114. PMID: 28328705.
  10. Yamazaki M, Miura Y, Tsuboi R, Ogawa H. Linear polarized infrared irradiation using Super Lizer is an effective treatment for multiple-type alopecia areata. Int J Dermatol. 2003 Sep;42(9):738-40. doi: 10.1046/j.1365-4362.2003.01968.x. PMID: 12956694.
  11. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3944668/

Leave a Reply

Your email address will not be published.