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Finasteride

Brand names: Proscar, Propecia

Finasteride shrinks an enlarged prostate and treats male-pattern hair loss.

Brand namesProscar, Propecia
Type of medicine5-alpha reductase inhibitor
Prescription?Prescription
ImportantThis page is general information, not a prescription. Don't start, stop, or change a medicine without talking to your provider or pharmacist.

Overview

It lowers DHT, a hormone that drives prostate growth and hair loss. It takes months to work.

What it's used for

  • Enlarged prostate (BPH)
  • Male-pattern hair loss

How to take it

  • Take it once a day, with or without food.
  • Benefits for hair stop if you stop taking it.
  • Women who are or may become pregnant shouldn't handle crushed or broken tablets.

Your dose depends on your health and other medicines. Always follow your prescription label, and ask your pharmacist if anything is unclear.

Side effects

Common side effects

  • Lower sex drive
  • Trouble getting an erection
  • Less semen
Call your provider todayBreast lumps, pain, or nipple discharge
Call your provider todayDepression or thoughts of self-harm
Call 911Swelling of the face, lips, or throat, hives, or trouble breathing

Warnings

  • It lowers PSA results; tell anyone checking your PSA that you take it.
  • Sexual side effects may continue after stopping in some men.

Other medicines, foods, and alcohol

  • Few major interactions.

Tell your provider and pharmacist about every medicine, vitamin, and supplement you take.

Pregnancy and breastfeeding

Not for use by women. It can cause birth defects in a male baby.

Missed doses, overdose, and storage

If you miss a dose

Take it as soon as you remember, unless it's almost time for your next dose. Then skip the missed dose. Don't take two doses at once.

If someone takes too much

Call Poison Control at 1-800-222-1222 or get help online at poison.org. Call 911 if the person collapses, has a seizure, has trouble breathing, or can't be woken.

Storing it

Store at room temperature, away from heat and moisture (not in the bathroom), and out of reach of children and pets.

Conditions it's used for

Sources

Last updated 2026-11-13.