The end result is a miniature follicle with no hair. The cause of the failure to grow a new hair is not well understood, but it is associated with a genetic predisposition and the presence of endocrine hormones (androgens), especially testosterone. The follicle, however, remains alive, suggesting the possibility of new growth. The typical pattern of male-pattern baldness begins at the hairline. The hairline gradually recedes to form an "M" shape.
The existing hair may be finer and does not grow as long as when younger. The hair at the crown also begins to thin, and eventually the top points of the hairline "M" meet the thinned crown, leaving a horseshoe pattern of hair around the sides of the head. Indications are absent hair or hair loss, receding hairline, hairline recedes from the front toward the back over time, thinning of hair,loss of hair at the crown of head progression of hair loss in a typical "M"-shaped pattern which eventually results in a loss of hair over the top of the head, and a horseshoe ring shape to remaining hair
Classic male-pattern baldness is usually diagnosed based on the appearance and pattern of hair loss. Hair loss that occurs in an atypical manner may be caused by other medical disorders. A skin biopsy or other procedures may be needed to diagnose other disorders that cause loss of hair.