Propecia (finasteride 1 mg) is an FDA-approved oral medication for the treatment of male pattern hair loss (androgenetic alopecia) in men. It works by blocking the conversion of testosterone to dihydrotestosterone (DHT), the hormone responsible for shrinking hair follicles and causing hair thinning over time. By lowering scalp DHT levels, Propecia helps slow hair loss, promote regrowth in some men, and improve hair density when taken consistently. It is typically prescribed for long-term use, with visible results often seen after 3 to 6 months. Propecia is available in tablet form for once-daily dosing and is not approved for use in women or children.