Light-Based Therapies for Alopecia: What’s Established and What’s Emerging

Interest in light-based therapies for alopecia has increased, driven by patient demand for noninvasive options and steady refinements in photobiomodulation technology. In a comprehensive 2025 review, Vanaria and colleagues examine how low-level light therapy (LLLT) and other laser-based modalities are being applied across a spectrum of alopecias, highlighting both established signals of efficacy and meaningful gaps that remain.

Rather than positioning LLLT as a replacement for pharmacologic therapy, the authors frame it as a biologically plausible adjunct—one that may improve follicular responsiveness, support adherence, and expand therapeutic choice. LLLT delivers low-energy red or near-infrared light (typically 620–680 nm, 1–9 J/cm²) to scalp tissue, where photons are hypothesized to interact with mitochondrial chromophores such as cytochrome c oxidase. This interaction increases ATP production, modulates reactive oxygen species, enhances microcirculation, and shifts follicles toward the anagen phase. These cellular effects underpin its application across multiple hair loss disorders.

The review is based on a structured PubMed search of English-language literature published primarily between 2020 and 2025, supplemented by citation tracking. Of 403 identified articles, 63 were selected for inclusion based on relevance to alopecia and light-based therapies. The included evidence spans randomized controlled trials, prospective studies, pilot trials, and case series, reflecting both the maturity and heterogeneity of the field.

Where LLLT Is Most Established
The strongest clinical signal emerges in androgenetic alopecia (AGA). Multiple randomized, double-blind, placebo-controlled trials demonstrate that LLLT increases terminal hair density and slows progression in both men and women. In one prospective, randomized, double-blind study of a dual-wavelength LED device, patients who were at least 80% compliant gained an average of 21 additional hairs per cm² after 16 weeks, while placebo-treated participants continued to lose hair. Importantly, dual-wavelength systems may also reduce dihydrotestosterone production via nitric oxide–mediated inhibition of 5α-reductase, offering a mechanistic complement to finasteride.

Combination therapy stands out as a recurring theme. Trials combining LLLT with topical minoxidil or oral finasteride consistently show greater improvements in hair density and patient satisfaction than monotherapy, suggesting a synergistic effect rather than simple additivity.

Emerging and Adjunctive Applications
Beyond AGA, the evidence becomes more exploratory but remains intriguing. In telogen effluvium, small studies suggest that LLLT may reduce shedding and subjectively improve density, even when increases in hair count do not reach statistical significance (p=0.143 in one pilot study). These findings align with LLLT’s ability to prolong anagen and support follicular metabolism during recovery phases.

In alopecia areata, light-based therapies appear to act through immunomodulatory pathways. Excimer laser treatments have demonstrated patch-level regrowth, while LLLT may reduce perifollicular inflammation and promote re-entry into anagen. Although data are limited, early studies report statistically significant improvements in hair counts and assessment scores after twice-weekly treatments.

Scarring alopecias, including lichen planopilaris and central centrifugal cicatricial alopecia, represent an area of cautious optimism. Case series describe reduced inflammation, symptom improvement, and partial regrowth with LLLT, particularly when initiated before irreversible fibrosis. While these observations are preliminary, they suggest a potential role for LLLT as a disease-stabilizing adjunct.

Practical Takeaways and Ongoing Limitations
Across indications, LLLT is consistently well tolerated, with mild, self-limited scalp pruritus as the most common adverse effect. At-home devices, particularly app-connected dual-wavelength systems, appear to improve adherence—an often-overlooked determinant of real-world outcomes.

At the same time, the authors are transparent about limitations, including small sample sizes, variable protocols, short follow-up, and occasional manufacturer sponsorship. Long-term durability, optimal dosing parameters, and predictors of response remain open questions.

Taken together, this review positions light-based therapy as a credible, evolving component of alopecia management, most convincingly in AGA, and increasingly as an adjunct in other hair loss disorders.

References

Vanaria RJ, Chaudry A, Nestor MS. The Use of Light-Based Therapies in the Treatment of Alopecia. J Cosmet Dermatol. 2025;24(9):e70434. doi:10.1111/jocd.70434