Dihydrotestosterone is the hormone formed in the prostate gland, testes, hair follicles, and adrenal glands when the enzyme 5-alpha reductase acts on testosterone. Traditionally considered a "male hormone", DHT is also produced by females in smaller quantities.

DHT is suspected to be a strong contributing factor in many cases of male baldness. The drug Finasteride (also sold as Propecia) reduces the activity of 5-alpha reductase and has been in use roughly since the year 2000 as a counter against this presumed cause of baldness. Equol is a DHT blocker.