The FDA has approved Dutasteride for treating BPH ( Benign Prostate Hyperplasia ), the same condition that Proscar, made by Merck, is used for. Dutasteride like Finasteride, (the active ingredient in Proscar and Propecia), also has the added benefit of being able to be used to treat genetic hair loss in men also known as Male Pattern Baldness or Androgenic Alopecia.
The difference between Dutasteride and Finasteride is that Dutasteride inhibits the activities of both type 1 and type 2 5AR ( 5-Alpha Reductase ) enzymes unlike Finasteride which mainly only inhibits type 2 5AR. These enzymes are responsible for the conversion of testosterone into DHT ( dihydrotestosterone ). DHT is the primary cause of prostate growth and hair loss and Dutasteride decreases serum blood levels of DHT by 90 percent after only two weeks making it a powerful weapon against hair loss and BPH ( note: DHT levels in the skin do not fall as dramatically as serum blood levels of DHT. DHT levels in the skin may be a more important factor in hair loss than serum blood levels ).