I have done some investigation into Propecia’s studies recently and have come across something that may be significant. It seems that in nearly all of the trials, the men who participated almost exclusively had hair loss at the crown.
My question therefore is, if side effects are caused by a certain hormonal profile, could there be any bias in studies where most of the men only have balding at the crown? Perhaps being predisposed to such a balding pattern makes you more likely to be immune to side effects from taking Propecia.
In my case it makes sense, since I have prolonged side effects after discontinuing finasteride treatment and only have recesson at the hairline, but what about everybody else?