Dihydrotestosterone (DHT) is an androgen, which is a hormone that stimulates the development of male characteristics through converting testosterone. The testes and prostate in men, and the ovaries in women, convert around 10% of daily testosterone to DHT. Many of the effects that testosterone has in the body only happen after it is converted to DHT.

Dihydrotestosterone makes male primary sex characteristics during embryonic life in the womb. DHT is also responsible for developing most secondary sex characteristics in males at puberty and male sexual function throughout adulthood. Less is known about its importance in women, but it is known to cause much of the body and pubic hair growth after puberty.

Elevated DHT levels may indicate hypogonadism (when the testes do not function properly) or hirsutism (excessive hair growth on a woman's face and body).