Q: Why does a hair transplant grow – why doesn’t the transplanted hair fall out? — J.F., Redding, C.T.

A: Hair transplants work because hair removed from the permanent zone in the back and sides of the scalp continues to grow when transplanted to the balding area in the front or top of one’s head. The reason is that the genetic predisposition for hair to fall out resides in the hair follicle itself, rather than in the scalp — this idea is called Donor Dominance. This predisposition is an inherited sensitivity to the effects of DHT, which causes affected hair to decrease in diameter and in length and eventually disappear — a process called “miniaturization.” When DHT resistant hair from the back of the scalp is transplanted to the top, it will continue to be resistant to DHT in its new location and grow normally.

Read more about Miniaturization
Read about the Causes of Hair Loss in Men