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 works 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. In hair follicles, this enhanced activity can stimulate growth, prolong the anagen phase (the active growing stage of hair), and reduce inflammation around the follicles that may impede healthy growth.

What Studies Say About Men

One of the earliest large-scale trials on LLLT for male pattern hair loss was conducted by Leavitt et al. (2009). This double-blind, randomized, sham device-controlled study involved 110 men with androgenetic alopecia—the most common type of hereditary hair loss. Participants used the HairMax LaserComb three times a week for 26 weeks, and their hair density was evaluated using phototrichograms, a technique that measures the number of hairs per square centimeter.

Results: Men who used the laser device showed a 17 hairs/cm² increase compared to the placebo group. The authors concluded that LLLT significantly improved hair density and thickness.

Criticism: While the study was FDA-cleared and peer-reviewed, it was funded by Lexington International, the manufacturer of the device, which may present a conflict of interest. Moreover, 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-controlled trial that included 128 women with mild to moderate androgenetic alopecia. Participants used a laser comb emitting 655-nm red light for 26 weeks, identical to the male study. Hair density was again measured using phototrichograms.

Results: The study showed an average increase of 20 hairs/cm², a slightly higher response compared to men. The researchers suggested that women might experience more visible improvement because they typically retain more hair follicles even in advanced stages of thinning.

Criticism: The trial's strength lies in its standardized design, but it shared the same funding source as the earlier male study. Additionally, the study population excluded women with hormonal or medical causes of hair loss, limiting the generalizability of the results.

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

A 2017 meta-analysis published in Lasers in Medical Science reviewed 11 clinical trials involving over 700 participants (both men and women). The researchers found that both sexes experienced significant hair density improvements compared to placebo, with no statistically significant difference between genders. However, they noted that individual response rates varied depending on the severity of hair loss, treatment frequency, and device type.

Further supporting this, Zhou et al. (2021) conducted a systematic review and meta-analysis of 15 studies (PubMed ID: 33677638). They confirmed that LLLT was effective in both men and women, showing an average hair density increase of 20–25% after 4 to 6 months of consistent use. The mechanisms appeared identical for both sexes—enhanced mitochondrial function and improved follicular metabolism.

Criticism: Despite solid evidence for efficacy, these 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. Because their follicles are not as severely miniaturized, LLLT can sometimes produce more noticeable cosmetic improvements in women, particularly when started early.

How Long Before Results Appear?

Most controlled trials indicate that visible results start around 16 to 24 weeks of consistent use. The therapy must be maintained, usually 3 times per week, to sustain growth. When discontinued, regrown hair may gradually shed as follicles revert to their natural cycle.

FDA and Safety Profile

The U.S. Food and Drug Administration (FDA) has cleared several LLLT devices for both men and women, including the HairMax LaserComb (2007) and iRestore Helmet (2018), for treatment of androgenetic alopecia. These approvals were based on randomized clinical trials demonstrating statistically significant increases in hair density and safety. Reported side effects are minimal, limited mainly to mild scalp redness or irritation.

So, Who Really Benefits More?

Based on the current body of research, both men and women benefit from LLLT. The magnitude of improvement depends more on the stage of hair loss, consistency of use, and overall follicle health than on gender. Women may perceive greater cosmetic improvement due to their typically diffuse thinning pattern, while men often use LLLT to slow down or partially reverse more advanced recession.

In short, LLLT is a gender-inclusive therapy. Its effectiveness relies on biology, not gender identity.

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/19409148/

• Zhou, Y., Zhang, L., Guan, X., Li, W., & Song, M. (2021). Efficacy of low-level laser therapy in treating androgenetic alopecia: A systematic review and meta-analysis of randomized controlled trials. Lasers in Medical Science, 36(8), 1687–1696. https://pubmed.ncbi.nlm.nih.gov/33677638

• U.S. Food and Drug Administration (FDA). (2007–2018). 510(k) Premarket Notification database—HairMax LaserComb, iRestore Laser System. https://www.fda.gov/medical-devices

• Perfect Hair Health. (2023). Evidence summary: Low-level laser therapy for hair loss. https://perfecthairhealth.com/low-level-laser-therapy/