Finasteride
is an
FDA-approved prescription medication used to treat male pattern hair loss
(androgenetic alopecia) at a 1 mg dose and an enlarged prostate (benign
prostatic hyperplasia or BPH) at a 5 mg dose. It works
by blocking the 5-alpha-reductase enzyme, which prevents testosterone from
converting into dihydrotestosterone (DHT)—the hormone responsible for shrinking
hair follicles and enlarging the prostate.
