How common is male pattern hair loss?

Male pattern hair loss affects nearly all men at some point in their lives. It affects different populations at different rates, probably because of genetics. Up to half of male Caucasians will experience some degree of hair loss by age 50, and possibly as many as 80% by the age of 70 years, while other population groups such as Japanese and Chinese men are far less affected.The severity of hair loss can be classified in several ways.