Who benefits most from low level laser therapy—men, women, or both?

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    Who Benefits Most from Low Level Laser Therapy—Men, Women, or Both?

    Low-level laser therapy (LLLT), also known as red light therapy, has become one of the most discussed non-invasive treatments for hair loss. Marketed as a safe and painless method to stimulate hair growth, LLLT uses specific wavelengths of light to target hair follicles and improve their cellular activity. But does it work equally well for everyone? Or are there meaningful differences between men and women when it comes to results? To answer this, we must look at what the research actually shows.

    The Science Behind the Light

    LLLT is thought to work through photobiomodulation, a process in which light energy is absorbed by the mitochondria—the energy-producing centers of our cells. When exposed to red or near-infrared light (typically between 630 and 680 nanometers), the mitochondria increase their production of adenosine triphosphate (ATP), which fuels cellular activity. The hypothesis is that, in hair follicles, this enhanced activity may stimulate growth, prolong the anagen phase (the active growing stage of hair), and reduce inflammation around the follicles. This has not been proven in people.

    What Studies Say About Men

    One of the earliest trials on LLLT for male pattern hair loss was conducted by Leavitt et al. (2009). This double-blind, randomized, sham device-controlled study enrolled men with androgenetic alopecia (Norwood-Hamilton IIa–V)—the most common type of hereditary hair loss. Men were randomized 2:1 to the HairMax LaserComb or a sham device, and 110 completed 26 weeks of treatment.

    Results: Men who used the laser device had a significantly greater increase in mean terminal hair density than the sham group. No serious adverse events were reported.

    Limits: The study did not assess whether results were maintained after treatment ended.

    What Studies Say About Women

    In 2014, Jimenez et al. published a multicenter, randomized, sham device-controlled, double-blind study that randomized 128 men and 141 women with pattern hair loss to a HairMax Lasercomb (one of three models) or a sham device, used three times a week for 26 weeks. Hair density was measured from masked digital photographs.

    Results: Terminal hair counts rose by 20.2 and 20.6 hairs/cm² in the two groups of women and by 18.4, 20.9 and 25.7 hairs/cm² in the three groups of men, compared with 1.6 to 9.4 hairs/cm² with the sham device. The authors found the increase was independent of the age and sex of the subject. No serious adverse events were reported.

    A smaller 2014 trial of a 655 nm helmet in 47 women over 16 weeks reported a 37% greater increase in hair counts than with a sham device, similar to an earlier trial of the same helmet in men (Lanzafame et al., 2014).

    Head-to-Head Comparisons: Are There Gender Differences?

    A 2017 systematic review in Lasers in Surgery and Medicine (Afifi et al.) looked at 11 studies with 680 patients (444 men and 236 women). Nine of the 11 studies that measured hair count or density found statistically significant improvements in both men and women; the authors advised caution in interpreting these findings.

    A 2021 meta-analysis of seven double-blind, randomized, sham-controlled trials of home-use devices (Lueangarun et al.) found a significant increase in hair density with active devices, and its subgroup analysis showed increased hair growth in both male and female subjects, with both comb and helmet devices.

    Criticism: Despite these positive results, the studies also highlight a lack of long-term follow-up data. We do not yet know how long results last once treatment stops.

    Biological and Hormonal Factors

    While both men and women benefit, hormonal environments can influence the degree of improvement. Androgenetic alopecia in men is primarily driven by dihydrotestosterone (DHT), a derivative of testosterone that shrinks hair follicles. LLLT does not block DHT but may help follicles resist its miniaturizing effects by improving their metabolic resilience.

    In women, hair thinning is often multifactorial—linked not only to androgens but also to hormonal shifts (like menopause) and nutritional deficiencies.

    How Long Before Results Appear?

    Controlled trials measured results after 16 to 26 weeks of use, about three times per week. None of the trials described here tested what happens after stopping.

    FDA and Safety Profile

    The U.S. Food and Drug Administration (FDA) first cleared the HairMax LaserComb for men in January 2007 (K060305); versions for women were cleared later (for example K112524, September 2011). iRestore was first cleared in January 2016 (K151662). These are 510(k) clearances, not approvals: the FDA found each device substantially equivalent to one already on the market. The trials above reported no serious adverse events.

    Most home devices use Class 3R lasers. The FDA says lasers in this class can be momentarily hazardous to the eye when a person looks directly into the beam, so do not look into the light or point it at the eyes.

    So, Who Really Benefits More?

    Based on the current research, sham-controlled trials report gains in both men and women, and the largest trial found the effect was independent of sex. Response varies between individuals, and the trials enrolled people with early to moderate hair loss, so there is little evidence for advanced baldness.

    In short, the evidence so far does not show that sex makes a clear difference to results. Talk to a doctor or pharmacist before starting or changing a hair-loss treatment.

    References (APA 7)

    • Jimenez, J. J., Wikramanayake, T. C., Bergfeld, W., Hordinsky, M., Hickman, J. G., Hamblin, M. R., & Schachner, L. A. (2014). Efficacy and safety of a low-level laser device in the treatment of male and female pattern hair loss: A multicenter, randomized, sham device-controlled, double-blind study. American Journal of Clinical Dermatology, 15(2), 115–127. https://pubmed.ncbi.nlm.nih.gov/24474647/

    • Leavitt, M., Charles, G., Heyman, E., Michaels, D., & HairMax LaserComb Clinical Study Group. (2009). HairMax LaserComb laser phototherapy device in the treatment of male androgenetic alopecia: A randomized, double-blind, sham device-controlled, multicentre trial. Clinical Drug Investigation, 29(5), 283–292. https://pubmed.ncbi.nlm.nih.gov/19366270/

    • Lanzafame, R. J., Blanche, R. R., Bodian, A. B., Chiacchierini, R. P., Fernandez-Obregon, A., Kazmirek, E. R. (2013). The growth of human scalp hair mediated by visible red light laser and LED sources in males. Lasers in Surgery and Medicine, 45(8), 487–495. https://pubmed.ncbi.nlm.nih.gov/24078483/

    • Lanzafame, R. J., Blanche, R. R., Chiacchierini, R. P., Kazmirek, E. R., & Sklar, J. A. (2014). The growth of human scalp hair in females using visible red light laser and LED sources. Lasers in Surgery and Medicine, 46(8), 601–607. https://pubmed.ncbi.nlm.nih.gov/25124964/

    • Afifi, L., Maranda, E. L., Zarei, M., et al. (2017). Low-level laser therapy as a treatment for androgenetic alopecia. Lasers in Surgery and Medicine, 49(1), 27–39. https://pubmed.ncbi.nlm.nih.gov/27114071/

    • Lueangarun, S., Visutjindaporn, P., Parcharoen, Y., Jamparuang, P., & Tempark, T. (2021). A systematic review and meta-analysis of randomized controlled trials of United States Food and Drug Administration-approved, home-use, low-level light/laser therapy devices for pattern hair loss: Device design and technology. Journal of Clinical and Aesthetic Dermatology, 14(11), E64–E75. https://pubmed.ncbi.nlm.nih.gov/34980962/

    • U.S. Food and Drug Administration. 510(k) K060305, HairMax LaserComb (Lexington International), decision 18 January 2007, substantially equivalent; product code OAP. https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm?ID=K060305

    • U.S. Food and Drug Administration. 510(k) K151662, iRestore Hair Growth System (Freedom Laser Therapy), decision 6 January 2016, substantially equivalent. https://www.accessdata.fda.gov/cdrh_docs/pdf15/K151662.pdf

    • U.S. Food and Drug Administration. Laser Products and Instruments. https://www.fda.gov/radiation-emitting-products/home-business-and-entertainment-products/laser-products-and-instruments

    • U.S. Food and Drug Administration. 510(k) K112524, HairMax LaserComb (Lexington International), decision 26 September 2011 (indication for females). https://www.accessdata.fda.gov/cdrh_docs/pdf11/K112524.pdf