Propecia is the real deal for most people. I know a guy who reversed his early MPB with it and Minoxidil.
That said, it doesn't work for everyone and it can have sides. Because it blocks the conversion from test to DHT, it affects hairloss caused by DHT, but ALSO sex drive. DHT is multiple times more powerful than Test and that CAN mean lowered libido and or impotence issues.
For me, my MPB is light, and I have been able to manage with just minoxidil when on cycle. The Propecia screwed too much with my sex life.
At the end of the day though, if you're serious about AAS, you're going to have to embrace either your hairline or your guns... No matter what drugs you take, if you put enough AAS in your body, you won't have that hair (on your head anyways) for long. My experience is, the people who are turned on by big muscle, aren't really the people who're too obsessed with your hair....