Maybe the key is "early onset baldness".

Proscar is the 5x dose of Propecia.

Proscar is used to reduce DHT to reduce the size of the prostate. Propecia is tha same medication in a smaller quantity that is used to reduce DHT in order to regrow hair.

Maybe it has to do with WHEN your body is producing an excess amount of DHT? I believe prostate issues are more common in the 35-40+ demographic, if I'm not mistaken.