Male Pattern Hair Loss or Androgenetic alopecia is the most common type of hair loss in men. It is caused by an interaction of a person’s genetic makeup and hormonal influences. Thinning and baldness occur in scalp hair progressively over time. The hairs become smaller and more fine through a process called miniaturization.
Miniaturization involves the hormone Testosterone that is circulating in our body. In the scalp it is converted into Dihydrotestosterone (DHT). DHT binds hair follicles that are sensitive to it and causes changes to the hair cycle. Over time, the hairs shrink until there is little or no hair visible.
Fortunately, the hairs present in the very back of the head are not subject to this type of hair loss and can last a lifetime. Hair transplant surgery involves moving this hair to other sites of the head that need it.
Evolution of Male Pattern Hair Loss
The Norwood Classification below shows the stages of hair loss progression that is typical for men if untreated.