Siah TW, Guo H, Chu T, et al. - Researchers conducted this randomized, blinded, placebo controlled, pilot clinical trial to discover the effectiveness of platelet rich plasma (PRP), processed from autologous peripheral blood, for hair growth promotion in androgenetic alopecia (AGA) individuals. In 10 AGA affected patients, the effectiveness of an 8 week, 5 sessions, PRP treatment course was determined by measuring hair density and hair caliber changes. The concentrations of selected growth factors were determined using a multiplex assay system for each PRP sample. According to this small pilot clinical trial, at 16 weeks, 8 weeks after the last PRP injection, treated areas displayed increased mean hair density (+12.76%) over baseline vs placebo (+0.99%). In both treated and placebo regions, the mean hair caliber reduced. Overall, a positive relationship was found between GDNF concentration and hair density. Findings suggested that PRP treatment can be advantageous for AGA. The variable responses to hair growth between patients, however, suggest that there is a major opportunity to improve hair growth promotion protocols for PRP therapy. The variability in the concentration of growth factors in PRP suggests that standardization of postprocessing growth factors might improve responses to hair growth.