Finasteride

Finasteride is a prescription oral medication that treats androgenetic alopecia by inhibiting the 5-alpha-reductase type II enzyme, which reduces levels of dihydrotestosterone (DHT) in the scalp. Taken typically as a 1 mg daily dose for male pattern hair loss, it can slow hair thinning and may promote hair regrowth over several months, with visible results often appearing after 3–6 months and needing ongoing use to maintain benefits.

Clinical studies show finasteride is effective for many men, particularly those with mild to moderate hair loss, but it can cause side effects such as decreased libido, erectile dysfunction, and mood changes in a small percentage of users; these effects are often reversible after stopping the drug. Finasteride is teratogenic and must not be used or handled by women who are pregnant or trying to conceive, and patients should discuss risks, potential interactions, and baseline health factors including PSA testing with their healthcare provider before starting treatment.