Effect of caffeine and testosterone on the proliferation of human hair follicles <i>in vitro</i>

The study investigated the effects of testosterone and caffeine on human hair follicles in vitro, using samples from 14 male patients with androgenetic alopecia (AGA). Testosterone at 5 µg/ml significantly suppressed hair follicle growth, but this effect was counteracted by caffeine at concentrations of 0.001% and 0.005%. Caffeine alone also significantly stimulated hair follicle growth. These findings, confirmed by Ki-67 staining, suggested that caffeine could be a potential stimulator of hair growth and may have clinical implications for managing AGA.