It is the most common type of hair loss in women and men. The reason of that is genetically determined sensitivity of hair follicles against the hormone called DHT (dihydrotestosterone). Actually, DHT is the active form of the hormone called testosterone found
in men and slightly in women. Because of the increasing in the activity of an enzyme called “5-alpha reductase”, testosterone begins to form DHT rapidly. DHT that damages the hair follicles causes weakness at the hair and has hair loss.
The greater the sensitivity to this hormone is the degree of hair loss is more.
In particular, there isn’t sensitivity region to DHT between the two ears in male, and therefore; at this region there is almost no possibility of hair loss. Hair follicles that are located in the donor in other words recipient site in hair transplantation continue their characters also in transported region.
Nonetheless, over polycystic that alters the oestrogen-androgen balance in women, hyperplastic over, carcinomas, pituitary hyperplasia, and various drugs (testosterone, danazol, adrenocorticotropic hormone, steroids, and progesterone) can also cause androgenetic alopecia.
After eliminating the underlying cause, hair transplantation to the balding or thinning areas gives good results at this type of loss.