Low-Level Light Therapy for Hair Loss

​Low-level light therapy can be used to promote hair growth

What Is Low-Level Light Therapy and How Is It Used for Alopecia?

Alopecia is a common disorder leading to hair thinning and hair loss. It affects many men and women worldwide and can be an emotionally devastating and anxiety provoking condition.[1] There are different forms of alopecia with different causes (See Table 1). 

Table 1. Types of Alopecia

Type of Alopecia

Who it Affects


Androgenetic Alopecia

(also known as male pattern baldness or female pattern baldness)

Androgenetic alopecia is the most common type of alopecia, affecting up to 50% of men by age 50 and up to 32% of women over age 20[2]

Many causes – genetic susceptibility, excess male sex hormones (DHT), low estrogen, insulin resistance

Telogen Effluvium[3]

Can affect anyone

Stress-induced hair loss – excess hair shedding following stressful events, trauma, severe illness, malnutrition, etc.

Alopecia Areata[4]

Affects up to 2% of Americans by age 50, with men and women equally affected

Autoimmune inflammatory disease, many have family history of alopecia areata

Scarring Alopecia[4]

Can affect anyone

Lupus erythematosus, lichen planopilaris, central centrifugal cicatricial alopecia

Medication Induced Hair Loss[4]

Women taking oral contraceptive pills, people taking chemotherapy medications, anti-thyroid medications, etc.

Medications such as chemotherapy drugs can destroy the rapidly dividing hair follicular cells, leading to hair loss

A first line treatment for many people with androgenetic alopecia includes the topical medications, minoxidil, and finasteride.[4] These medications may not work for everyone. In order to be effective, they must be used indefinitely and can be burdensome by the need to use them daily. Another option is surgical hair transplantation, which is limited by many factors including cost, individual hair distribution and donor hair supply.[5] 

An emerging treatment option for alopecia is Low-Level Light Therapy. The United States Food and Drug Administration (FDA) cleared Low-Level Light Therapy devices for marketing as an effective and safe option for male and female androgenetic alopecia.[6] Low-Level Light Therapy can be done as an in-office treatment, or people can purchase commercially available devices for use at home.

Low-Level Light Therapy Devices for Alopecia

  • HairMax® LaserComb and LaserBand – FDA approved to promote hair growth in men and women with androgenetic alopecia.[7]
  • iRestore™ Hair Growth System – this at home device was cleared for marketing by the FDA to treat hair loss in men and women.[8]
  • iGrow Hair Growth System® - at home helmet device cleared for marketing by the FDA to promote hair growth in men and women with androgenetic alopecia.[9]
  • Super Lizer – Japanese device shown to improve hair growth in patients with alopecia areata.[10]


How Does Low-Level Light Therapy for Alopecia Work?

There are several proposed mechanisms for how Low-Level Light Therapy works for alopecia although the exact mechanism is not yet known.  Most devices and studies have used wavelengths of red light ranging from 635 to 900 nm.[11]

Proposed Mechanisms for Low-Level Light Therapy

  • One mechanism suggests that Low-Level Light Therapy targets a tiny organelle within our cells. This might lead to an alteration in cellular metabolism, increased ATP production (an energy molecule), and production of messenger molecules called transcription factors that increase hair growth promoting proteins.[12]
  • Low-Level Light Therapy may increase production of nitric oxide (NO), leading to greater blood flow to hair follicles.[13]
  • Low-Level Light Therapy may alter production of dihydrotestosterone (DHT), which is a hormone implicated in the cause of androgenetic alopecia.[14]
  • Low-Level Light Therapy may modulate the immune system and inflammatory responses that are important in normal hair growth.[12]


What Condition Does Low-Level Light Therapy Treat? 

FDA-cleared uses for Low-Level Light Therapy: Most Low-Level Light Therapy devices available on the market are approved to promote hair growth in men and women with androgenetic alopecia.


How Is Low-Level Light Therapy Done?

Low-Level Light Therapy for alopecia is available as at-home devices, in the salon setting, or as treatments in a health practitioner’s office. Low-Level Light Therapy devices deliver red light (650-900 nm wavelength light) at 5 mW.[15]  Most clinical studies demonstrated the best results when people used the Low-Level Light Therapy device daily or every other day for approximately 10-20 minutes per treatment for four to six months.[16]

Some devices operate by a comb with lights that the person can move across their scalp for the instructed amount of time. Other devices consist of a helmet that covers the entire scalp for the duration of the treatment. Despite promising clinical results, there is still limited evidence on whether at-home Low-Level Light Therapy devices are as effective for alopecia as receiving treatment in a licensed practitioner’s office.[6,10]


What Are the Common Side Effects and Risks of Low-Level Light Therapy?

Low-Level Light Therapy is generally well tolerated with a low incidence of adverse events. Side effects may include headaches, skin pain or burning, itching, scalp redness, and mild tingling.[16]

* This Website is for general skin beauty, wellness, and health information only. This Website is not to be used as a substitute for medical advice, diagnosis or treatment of any health condition or problem. The information provided on this Website should never be used to disregard, delay, or refuse treatment or advice from a physician or a qualified health provider.


  1. Spahn G, Plettenberg H, Nagel H, et al. Evaluation of cartilage defects with near-infrared spectroscopy (NIR): an ex vivo study. Med Eng Phys.2008;30(3):285-292; PMID: 17553725.
  2. Olsen EA, Messenger AG, Shapiro J, et al. Evaluation and treatment of male and female pattern hair loss. J Am Acad Dermatol.2005;52(2):301-311; PMID: 15692478.
  3. Sinclair R. Chronic telogen effluvium: a study of 5 patients over 7 years. J Am Acad Dermatol.2005;52(2 Suppl 1):12-16; PMID: 15692504.
  4. Otberg N, Shapiro J. Hair Growth Disorders. In: Goldsmith LA, Katz SI, Gilchrest BA, et al., eds. Fitzpatrick's Dermatology in General Medicine. 8 ed: McGraw Hill; 2012.
  5. Rogers NE, Avram MR. Medical treatments for male and female pattern hair loss. J Am Acad Dermatol.2008;59(4):547-566; quiz 567-548; PMID: 18793935.
  6. Wikramanayake TC, Rodriguez R, Choudhary S, et al. Effects of the Lexington LaserComb on hair regrowth in the C3H/HeJ mouse model of alopecia areata. Lasers Med Sci.2012;27(2):431-436; PMID: 21739260.
  7. FDA. 510(k) SUMMARY Lexington International, LLC LaserComb. Food and Drug Administration;2009.
  8. FDA. 510(k) Summary iRestore Hair Growth System. Food and Drug Administration;2016.
  9. FDA. 510(k) Summary Aspira Science, inc. igrow-II Hair Growth System. Food and Drug Administration;2012.
  10. Yamazaki M, Miura Y, Tsuboi R, et al. Linear polarized infrared irradiation using Super Lizer is an effective treatment for multiple-type alopecia areata. Int J Dermatol.2003;42(9):738-740; PMID: 12956694.
  11. Avci P, Gupta GK, Clark J, et al. Low-level laser (light) therapy (Low-Level Light Therapy) for treatment of hair loss. Lasers Surg Med.2014;46(2):144-151; PMID: 23970445.
  12. Chung H, Dai T, Sharma SK, et al. The nuts and bolts of low-level laser (light) therapy. Ann Biomed Eng.2012;40(2):516-533; PMID: 22045511.
  13. Makihara E, Masumi S. Blood flow changes of a superficial temporal artery before and after low-level laser irradiation applied to the temporomandibular joint area. Nihon Hotetsu Shika Gakkai Zasshi.2008;52(2):167-170; PMID: 18467786.
  14. Castex-Rizzi N, Lachgar S, Charveron M, et al. [Implication of VEGF, steroid hormones and neuropeptides in hair follicle cell responses]. Ann Dermatol Venereol.2002;129(5 Pt 2):783-786; PMID: 12223959.
  15. Rangwala S, Rashid RM. Alopecia: a review of laser and light therapies. Dermatol Online J.2012;18(2):3; PMID: 22398224.
  16. Zarei M, Wikramanayake TC, Falto-Aizpurua L, et al. Low level laser therapy and hair regrowth: an evidence-based review. Lasers Med Sci.2016;31(2):363-371; PMID: 26690359.
  17. Frigo L, Luppi JS, Favero GM, et al. The effect of low-level laser irradiation (In-Ga-Al-AsP - 660 nm) on melanoma in vitro and in vivo. BMC Cancer.2009;9:404; PMID: 19930543.