What it is used for

Symptoms of an enlarged prostate (5mg)
Male pattern hair loss (1mg, private prescription)

Read our guides:

Enlarged prostate (BPH)

Off-label uses

Doctors sometimes prescribe a medicine for a condition it is not officially licensed for. This is called off-label use. It is legal and common when there is good evidence it helps, and your doctor should explain why they are suggesting it.

Excess hair growth in women (hirsutism), under a specialist

How it works

Finasteride blocks an enzyme that turns testosterone into dihydrotestosterone (DHT). Lower DHT shrinks the prostate and slows hair loss.

Side effects

Like all medicines, Finasteride can cause side effects, although not everyone gets them. Many are mild and ease after the first few weeks.

Common side effects

erection problems
lower sex drive
less semen
breast tenderness or swelling

Tell your doctor or pharmacist if these bother you or do not go away.

Serious side effects

These are rare. Call 111 or contact your doctor straight away if you get:

low mood, depression or thoughts of harming yourself. Stop and see a doctor
breast lumps, pain or nipple discharge

Call 999 if you have signs of a serious allergic reaction, such as swelling of your lips, mouth, throat or tongue, or trouble breathing.

You can report any side effect to the Yellow Card scheme, run by the medicines regulator.

Stopping and withdrawal

Important safety information

The medicines regulator warns about depression and suicidal thoughts. Tell your doctor about any mood changes.
Women who are or may become pregnant should not handle crushed or broken tablets.
It lowers PSA test results.

Questions about your medicine?

A pharmacist can answer questions about your medicines for free, without an appointment. You can also ask your GP for a medication review. Check if you can get free prescriptions.