It has been suggested that high DHT levels in genetically predisposed hair follicles initiate baldness.

It is this chemical conversion from testosterone to dihydrotestosterone that is blocked by hair restoration products, such as finasteride, which is a prescription medicine and the active ingredient in Propecia, another prescription medication to treat hair loss.

 Finasteride blocks the formation of active testosterone and allows those hairs predisposed to inactivity to become active again and make new hairs.