Male pattern hair loss is a common condition in which men experience thinning of the hair on the scalp. These changes typically begin gradually in men in their 20s.
Doctors believe male pattern hair loss is due to heredity and is dependent on hormonal effects.
Doctors refer to this type of hair loss as androgenetic alopecia. Of these men, approximately 1200 with hair loss at the top of the head were studied for an additional 12 months. In one study, patients were questioned on the growth of body hair. Although results will vary, generally you will not be able to grow back all of the hair you have lost. Male pattern hair loss occurs gradually over time.