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.
