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Article · Wellness Equipment

Red Light Therapy for Hair Loss: What the Meta-Analyses Show

What meta-analyses of 38 studies found for red light and laser caps in pattern hair loss, the first FDA-cleared laser comb, and the caveats in the trials.

Related guide

Red Light Therapy Benefits: What the Research Shows

By Wellness Equipment
On this page
  1. What the meta-analyses found
  2. The FDA-cleared comb
  3. Limitations: what the trials don’t show
  4. Sources

Hair loss is where light therapy has its longest regulatory history. FDA cleared the first laser comb for hair growth in January 2007.

This article covers what the pooled trials show and where they fall short. It sits under our overview of red light therapy benefits. It is general information, not medical advice: see a dermatologist to confirm the type of hair loss first.

Short answer: for pattern hair loss, the evidence is among the best for any red light use. A 2025 meta-analysis of 38 studies and 3,098 patients found more hair density than placebo, and a 2020 review found every sham-controlled trial positive. However, many trials were small or industry-linked, and other types of hair loss lack data.

What the meta-analyses found

Perez (2025) found the largest pooled result. The meta-analysis in Dermatologic Surgery covered 38 studies and 3,098 patients, 2,930 of them with androgenetic alopecia. Compared with placebo, hair density rose in treatments under 20 weeks (standardized mean difference 1.14) and over 20 weeks (1.44). The authors call it “a promising treatment option” for pattern hair loss.

Review What it pooled Finding
Perez, Dermatologic Surgery, 2025 38 studies, 3,098 patients More hair density than placebo in pattern hair loss
Egger, Skin Appendage Disorders, 2020 10 trials, 8 sham-controlled Every sham-controlled trial positive
Delaney, J Cosmetic and Laser Therapy, 2018 Double-blind trials Positive, but “must be interpreted with caution”

The 2020 review put it plainly:

“All sham-device controlled studies demonstrated statistically significant increase in hair diameter or density (p < 0.01).”

Egger A, et al., Skin Appendage Disorders, 2020

The FDA-cleared comb

FDA’s 510(k) database lists the HairMax LaserComb from Lexington International, cleared on January 18, 2007, under product code OAP (“Laser, Comb, Hair”). A 510(k) clearance means FDA found the device substantially equivalent to one already on the market. FDA Cleared vs. Approved vs. Registered Devices explains the difference.

Limitations: what the trials don’t show

According to the 2020 review, some included studies had industry ties. The 2018 review asked for larger trials, longer follow-up, and independent funding. A 2017 review in Dermatologic Surgery found the trials hard to compare because of small samples and varied lengths, and recommended 12-month studies.

Evidence for other hair loss types is thin. The 2025 meta-analysis found only 5 studies on alopecia areata, scarring alopecia, and other types, too few to pool.

Adding light to minoxidil is also unsettled. Mawu (2025) reported more hair density with the combination across 7 trials, while Alosaimi (2025) found no difference in hair counts across 4 trials.

Here’s what the spec sheet won’t tell you. Most hair trials used caps, helmets, or combs worn on the scalp. A wall panel at arm’s length delivers a different dose, and none of these trials tested one.

My rule of thumb: give any device 20 weeks, the shorter of the two time frames in the 2025 meta-analysis, before deciding it works.

Bottom line: red light and low-level laser devices have fair evidence for pattern hair loss, backed by an FDA-cleared comb since 2007. The trials are small and often industry-linked. For the other claims, see the red light therapy benefits overview linked above.

Sources

  • Perez SM, et al., “Low-Level Laser and LED Therapy in Alopecia: A Systematic Review and Meta-Analysis,” Dermatologic Surgery, 2025 (abstract): pubmed.ncbi.nlm.nih.gov
  • Egger A, et al., “Examining the Safety and Efficacy of Low-Level Laser Therapy for Male and Female Pattern Hair Loss: A Review of the Literature,” Skin Appendage Disorders, 2020 (abstract): pubmed.ncbi.nlm.nih.gov
  • Delaney SW, et al., “Systematic review of low-level laser therapy for adult androgenic alopecia,” Journal of Cosmetic and Laser Therapy, 2018 (abstract): pubmed.ncbi.nlm.nih.gov
  • Gupta AK, et al., “A Critical Assessment of the Evidence for Low-Level Laser Therapy in the Treatment of Hair Loss,” Dermatologic Surgery, 2017 (abstract): pubmed.ncbi.nlm.nih.gov
  • Mawu FO, et al., Lasers in Medical Science, 2025 (abstract): pubmed.ncbi.nlm.nih.gov
  • Alosaimi A, et al., The Journal of Dermatological Treatment, 2025 (abstract): pubmed.ncbi.nlm.nih.gov
  • U.S. Food and Drug Administration, 510(k) Premarket Notification K060305, HairMax LaserComb, decision date January 18, 2007: accessdata.fda.gov

Not medical advice.This page is general product information. Heat and cold exposure aren't safe for everyone. Talk to a physician before starting a sauna or cold plunge routine, particularly if you are pregnant or have a heart, blood pressure, or circulation condition. See our Editorial Policy.

Frequently Asked Questions

Does red light therapy regrow hair?

For androgenetic alopecia (pattern hair loss), a 2025 meta-analysis of 38 studies and 3,098 patients found hair density rose more with low-level light than with placebo. Evidence for other types of hair loss is too thin to pool.

Are laser caps and combs FDA-cleared?

Some are. FDA's 510(k) database shows the HairMax LaserComb cleared on January 18, 2007, under product code OAP. Clearance means FDA found it substantially equivalent to an existing device, not that it was approved as a drug.

Is red light better than minoxidil?

The trials don't settle it. Two 2025 meta-analyses that added light to minoxidil disagreed: one found more hair density with the combination, the other found no difference in hair counts.