What makes the results of a hair transplant permanent? I would think that any hair you put in a balding portion of the scalp would just fall out eventually, especially since it is still your own hair. Why does this happen?
This is a very good question, however the underlying premise is wrong unfortunately. The hair falls out because of the hair itself, which is genetically primed to last to a certain age. Hair that has been genetically primed to be permanent, meaning the hair in the back and the sides of the head in a male, is the hair that is used for a transplant. It does not matter if it is placed in an area where the hair was previously primed to fall out at an early age because the new hair is set to last a lifetime.
You can put hair that is genetically primed to last a lifetime anyplace that there is a good blood supply and it will last according to how it is genetically set up, which again in this case would be for a lifetime. The fact that it is your own hair just simply means that the hair itself will not be rejected on transplantation.