Abstract
Androgenetic alopecia (AGA) is the most common form of hair loss, affecting up to 80%
of men and 50% of women in the course of their life. It is caused by a progressive reduction
in the diameter, length, and pigmentation of the hair. Hair thinning is limited to the frontal,
temporal, and vertex areas (androgen-dependent scalp regions) and results from the effects
of the testosterone metabolite dihydrotestosterone (DHT) on androgen-sensitive hair follicles.
Androgen sensitivity is genetically determined and depends on DHT production through the
enzyme 5α-reductase.