I visited an endocrinologist and he found my testosterone level to be normal. He said giving me testosterone has a lot of side effects, such as breast enlargement and shrinkage of testicles. The problem is not that I don't have hair at all, but they are very very tiny hair pieces that have not increased by shaving. The amount and distribution of ones hair growth is mainly dictated by your parents. In particular by your father and your mother's father.
Facial hair is very similar to hair in other parts of the body.
There doen't seem to be any way to induce hair growth which will last. Use of rogaine on the face should work, but must be performed every day or the effect will begin to vanish. I am now 29. I noticed the thinning after a 3 month period of taking Fastin for weight reduction. Recently I was prescribed prednisone for an allergic reaction to an unknown source.