The disease typically begins at the hairline. The hair follicles that are most sensitive to DHT are located at the temples, the hairline and on the crown of the head. Male Pattern Baldness gets its name from this “pattern” of sensitive hair follicles.

The culprit is a hormone called dihydrotestosterone (DHT), which is converted from testosterone in the scalp. Over time, DHT builds up around the hair follicle, thinning or “miniaturizing” the hair and ultimately stopping growth. The follicle regresses as a result, causing each new hair that cycles through the follicle to be gradually thinner than the previous one. Eventually the follicle shuts down altogether, ending hair growth completely and permanently. Both a follicles resistance to DHT and the levels of DHT in the scalp are genetically determined , which explains why some people go bald and others do not. The gene can be inherited from both the mother and the father, so men with balding relatives (on either side of the family) have increased odds of losing their hair too.

The hair line often recedes to form an “M” shape Hair at the crown of the head begins to thin. Existing hair becomes finer and shorter. The top of the hairline eventually meets the thinned crown, leaving a horseshoe pattern of hair around the sides of the head that continues to grow.

Other hair loss causes account for 10% of cases in men (and an even larger percent of hair loss in women). Hair loss in patches, diffused shedding of hair, breaking hair shafts, or hair loss associated with redness, scaling, pain or rapid progression is probably indicative of a condition other than Male Pattern Baldness. These different types of hair loss can be caused by medical conditions, poor nutrition, certain medications, stress or other factors. If any of these symptoms are present in conjunction with hair loss, it is recommended to consult a physician.