Androgenic alopecia or male pattern baldness (MPB) is responsible for the vast majority of hair loss in men. While there are many possible reasons people lose their hair, including serious disease, reaction to certain medications, and in rare cases extremely stressful events, most hair loss in men can be blamed on heredity.
What male pattern baldness sufferers are actually inheriting are hair follicles with a genetic sensitivity to Dihydrotestosterone (DHT). Hair follicles that are sensitive to DHT begin to miniaturize, shortening the lifespan of each hair follicle affected. Eventually, these affected follicles stop producing cosmetically acceptable hair.
Male pattern baldness is generally characterized with the onset of a receeding hairline and thinning crown. Hair in these areas including the temples and mid-anterior scalp appear to be the most sensitive to DHT. This pattern eventually progresses into more apparent baldness throughout the entire top of the scalp, leaving only a rim or "horseshoe" pattern of hair remaining in the more advanced stages of MPB. For some men even this remaining rim of hair can be affected by DHT.
A closer look at DHT
Dihydrotestosterone (DHT) is a derivative or by-product of testosterone. Testosterone converts to DHT with the aid of the enzyme Type II 5-alpha-reductace, which is held in the hair follicle's oil glands. While the entire genetic process of male pattern baldness is not completely understood, scientists do know that DHT shrinks hair follicles, and that when DHT is suppressed, hair follicles continue to thrive. Hair follicles that are sensitive to DHT must be exposed to the hormone for a prolonged period of time in order for the affected follicle to complete the miniaturization process. Today, with proper intervention this process can be slowed or even stopped if caught early enough.