On average 20 percent of the world's male population report hair loss during their lifetime. Hair loss can begin as early as the teenage years; by age 35 almost 40 percent of men demonstrate some degree of hair loss. Propecia (finasteride) is the first prescription oral medication for the effective treatment of male pattern hair loss. In clinical trials Propecia was shown to: Maintain or increase the amount of hair in 83 percent of men. # Promote visible hair regrowth in 66 percent of men. # Reduce the level of dihydrotestosterone (DHT), an apparent cause of hair lossDemonstrate an excellent safety profile.