Platelet-rich plasma as a therapy for androgenic alopecia: a systematic review and meta-analysis.

OBJECTIVE: The past decade has seen platelet-rich plasma (PRP) become a popular therapy around the world as a treatment for androgenetic alopecia (AGA). These systematic review and meta-analyses assess the effectiveness and adverse effects of PRP to determine the role of PRP as a treatment for AGA among the other non-surgical treatment modalities. METHODS: This study follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and is registered under the PROSPERO ID CRD42019136329. Seven databases were searched from inception through May 2019. Meta-analyses of randomized controlled trials (RCTs) were performed to evaluate the effect of PRP treatments on hair density and hair thickness. RESULTS: Thirty studies, including 687 patients, met our inclusion criteria. Twenty-nine studies reported beneficial results, and 24 studies reached statistical significance on a measured outcome. Ten RCTs were included. Our meta-analyses show that PRP treatment increases hair density and hair thickness. CONCLUSIONS: PRP is an autologous treatment that lacks serious adverse effects and effectively improves hair density and hair thickness in men and women with AGA. Future research should include low risk-of-bias RCTs to optimize treatment protocols, investigate variability among studies, and to obtain more data on hair thickness changes.