The effectiveness of treatments for androgenetic alopecia: A systematic review and meta-analysis

Background: Androgenetic alopecia, or male pattern hair loss, is a hair loss disorder mediated by dihydrotestosterone, the potent form of testosterone. Currently, minoxidil and finasteride are Food and Drug Administration (FDA) eapproved, and HairMax LaserComb, which is FDA-cleared, are the only treatments recognized by the FDA as treatments of androgenetic alopecia. Objective: This systematic review and meta-analysis assesses the efficacy of nonsurgical treatments of androgenetic alopecia in comparison to placebo for improving hair density, thickness, growth (defined by an increased anagen: telogen ratio), or subjective global assessments done by patients and investigators. Methods: A systematic review of randomized controlled trials was conducted. PubMed, Embase, and Cochrane were searched up to December 2016, with no lower limit on the year. We included only randomized controlled trials of good or fair quality based on the US Preventive Services Task Force quality assessment process. Results: A meta-analysis was conducted separately for 5 groups of studies that tested the following hair loss treatments: low-level laser light therapy in men, 5% minoxidil in men, 2% minoxidil in men, 1 mg finasteride in men, and 2% minoxidil in women. All treatments were superior to placebo (P<.00001) in the 5 meta-analyses. Other treatments were not included because the appropriate data were lacking. Limitations: High heterogeneity in most studies. Conclusions: This meta-analysis strongly suggests that minoxidil, finasteride, and low-level laser light therapy are effective for promoting hair growth in men with androgenetic alopecia and that minoxidil is effective in women with androgenetic alopecia.