Finasteride is a prescription oral medication belonging to the 5-alpha-reductase inhibitor class, which works by blocking the conversion of testosterone to dihydrotestosterone (DHT) — the potent androgen implicated in male-pattern hair loss (androgenetic alopecia). In men who are beginning to experience hair-line recession or crown thinning, finasteride has been shown in clinical trials to slow or halt hair loss and in some cases stimulate modest regrowth of scalp hair, especially when started early in the hair-loss process. Treatment should be continued long-term to maintain benefit; cessation of therapy often leads to reversal of gains and resumed hair shedding within months. Although generally well tolerated, finasteride’s side-effect profile includes decreased libido, erectile dysfunction, and ejaculation disorder in a minority of users — and these effects typically resolve when the medication is discontinued. It is contraindicated in women who are or may become pregnant, as it may cause abnormalities in a male fetus if exposed. For hair-line control in men, finasteride is a validated option — but users should consult their clinician about long-term commitment, monitoring, and realistic expectations (regrowth is modest, and individual responses vary). In summary, finasteride offers a medically-supported pharmacologic approach to slowing or reversing certain patterns of androgen-driven hair loss when used appropriately.
