Autologous platelet-rich plasma therapy for pattern hair loss: A systematic review.

BACKGROUND: Androgenetic alopecia (male pattern and female pattern hair loss) is characterized by thinning of the scalp hair. Intradermal injection of autologous platelet-rich plasma (PRP) might have an effect on hair regrowth. AIMS: The aim was to evaluate efficacy and safety of platelet-rich plasma compared to placebo or no treatment in people with pattern hair loss. PATIENTS/METHODS: We searched the databases CENTRAL and MEDLINE on December 24, 2018 and included randomized controlled trials (RCTs). Primary outcomes were mean change of hair density from baseline and serious treatment-related adverse events. Secondary outcome was mean change of hair thickness from baseline. Time point of outcome assessment was 6 months after start of treatment. RESULTS: We identified 13 relevant randomized controlled trials with 356 randomized (343 analyzed) people or half-head areas who received PRP in a simple parallel or half-head design. The pooled data of seven studies (171 analyzed people or half-head areas) were favorable in the PRP group on hair density. We estimated a mean difference from baseline of 30.35 associated with a wide 95% confidence interval (1.77-58.93), a considerable heterogeneity (I 2 = 100%), and unclear risk of bias in most of the studies. Regarding hair thickness, data were also favorable in the PRP group, but these data were limited to a single study. We did not identify serious treatment-related adverse events. CONCLUSION: The results of seven RCTs indicated that autologous platelet-rich plasma was associated with an increase of hair density when compared to placebo.