Platelet-Rich Plasma for Treating Androgenic Alopecia: A Systematic Review.

BACKGROUND: Platelet-rich plasma (PRP) contains a variety of growth factors and proteins that can accelerate tissue repair. Androgenic alopecia is a genetic disorder characterized by atrophy of hair follicles and hair loss. At present, PRP injections for hair restoration have become a popular though controversial practice. We conducted a meta-analysis to compare the differences between patients treated with local injections of PRP and control group subjects to explore the effectiveness of PRP treatment for androgenic alopecia. MATERIALS AND METHODS: We searched PubMed, EMBASE and the Cochrane Library until Jan 2019 for human studies evaluating the efficacy of PRP for the treatment of androgenic alopecia. RESULTS: We retrieved 132 papers; 11 articles matched our inclusion criteria and comprised 262 androgenic alopecia patients. Through a meta-analysis, we found a significantly locally increased hair number per cm2 after PRP injections in the treatment group versus the control group (mean difference 38.75, 95% CI 22.22-55.28, P < .00001). Similarly, a significantly increased terminal hair density was found in the PRP group compared with the control group (mean difference 22.83, 95% CI 0.28-45.38, P = 0.05). CONCLUSION: Most studies suggest that subcutaneous injection of PRP is likely to reduce hair loss, increase hair diameter and density in patients with androgenic alopecia. Because of the low quality of the studies, small sample sizes, different treatment regimens and possible publication bias, the results of this meta-analysis should be interpreted with caution. Furthermore, more randomized controlled studies should be performed. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .