androgenetic alopecia
"When I turned 50, I went in for a physical. The doctor noticed my hair was thinning and recommended Propecia. That was 14 years ago and today I have a very full head of hair, especially for a 64 yo.  Two issues, one it must be taken religiously. I take it at least  350+ times a year. Two, its not cheap. Generics are available on the internet. My brother was born 10 months before me. Physically, we are very similar. During our youth, our hair was almost identical. Today, he is balding, badly. Side affects. Shortly after I starting taking it, I DID have trouble getting an erection, but the problem went away after a number of weeks. I was thinking of quitting, but just wanted to give my body a little more time to adjust. And it did. No regrets"