Platelet-rich plasma for androgenetic alopecia: Efficacy differences between men and women.

Platelet-rich plasma (PRP) may be effective for treating androgenetic alopecia (AGA); albeit, its efficacy in men and women is still debated. We conducted meta-analyses to determine PRP efficacy in men and women separately. Studies were identified after systematically searching for trials that investigated PRP monotherapy for AGA in men and women separately. We included trials that studied PRP injections on hair density and/or hair diameter. Pooled effect of PRP was determined using a random effects model. For men, PRP significantly increased hair density from baseline (pooled sample size [N] = 250, mean difference [MD] = 25.83, 95% confidence interval [CI]: 15.48-36.17, P < .00001) and significantly increased hair diameter (N = 123, MD = 6.66, 95% CI: 2.37-10.95, P = .002). For women, PRP significantly increased hair diameter (N = 95, MD = 31.22, 95% CI: 7.52-54.91, P = .01), but not hair density (N = 92, MD = 43.54, 95% CI: -1.35-88.43, P = .06). Subgroup analyses indicated that PRP prepared by the double spin method significantly increased hair density in men (N = 131, MD = 32.83, CI: 21.14-44.52, P < .00001), while the single spin method did not (N = 88, MD = 21.61, CI: -2.03-45.26, P = .07). In the studies evaluated, PRP significantly increased hair diameter in men and women, but significantly increased hair density only in men. PRP effectiveness may be increased by using higher concentrations of platelets.