Low-Level Laser and LED Therapy in Alopecia: A Systematic Review and Meta-Analysis

BACKGROUND: Low-level laser/LED therapy (LLLT) has been described as a treatment option for alopecia, but no study has comprehensively reviewed its efficacy in multiple alopecia types. OBJECTIVE: To review and evaluate LLLT for various alopecia types. MATERIALS AND METHODS: A systematic search of PubMed/MEDLINE, Embase, and CENTRAL was conducted to identify studies assessing the effect of LLLT on patients diagnosed with alopecia. Prespecified outcome measure was the change in hair density. Meta-analysis was performed to calculate the standardized mean difference in hair density before and after LLLT compared with placebo. RESULTS: Thirty-eight studies were included that described 3,098 patients with androgenetic alopecia (2,930/3,098), scarring alopecia (49/3,098), alopecia areata (50/3,098), telogen effluvium (17/3,098), and chemotherapy-induced alopecia (32/3,098). The mean change in hair density increased significantly in androgenetic alopecia patients after LLLT for 4 to 26 weeks compared with placebo (<20 weeks: SMD = 1.14; 95% CI [0.51-1.78]; p = .000; I 2 = 88.26%; >20 weeks: SMD = 1.44; 95% CI [0.97-1.91]; p = .000; I 2 = 80.81%). Change in hair density was reported in 5 studies evaluating other alopecia types; however, statistical information was insufficient for meta-analysis. CONCLUSION: LLLT is a promising treatment option for patients with androgenetic alopecia, but future studies are needed to better understand its efficacy in other alopecia types.