AR and androgenetic alopecia: In hair follicles, increased expression patterns for both 5αR2 and AR have been associated with androgenetic alopecia [19] and treatment of androgenetic alopecia with 5α-reductase inhibitors (5ARIs) such as finasteride is a definite proof of the involvement of DHT in clinical manifestations of androgen activity as well as side effects of 5ARIs (such as impaired sexual function and more frequent psychological and cognitive complaints), putatively inhibiting especially the cerebral 5αR3 isomer [20–24].