Medication questions Finasteride

Is there an age limit for taking finasteride for hair loss?

Short answer

Under 18, no: the UK product information says finasteride is not indicated for children and adolescents. From 18, the licence for male pattern hair loss sets no upper age limit, but the main trials enrolled men aged 18 to 41, so there is less trial evidence outside that range. A doctor decides whether it is appropriate at your age, and the MHRA mood and sexual warnings apply at every age.

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Key facts

  • Under 18: not indicated. The SmPC says there are no data demonstrating efficacy or safety in children under 18.
  • The licence for male pattern hair loss in men has no stated upper age limit.
  • The clinical studies behind the licence enrolled 1,879 men aged 18 to 41.
  • No dose change is needed in older men (SmPC), but finasteride lowers PSA, which matters for prostate checks.
  • Finasteride is for men. It is contraindicated in women because of the risk in pregnancy.

Under 18

The Propecia summary of product characteristics (SmPC) says finasteride is not indicated for use in children or adolescents, and that there are no data demonstrating efficacy or safety in children under 18. Hair loss in teenagers also has many causes other than pattern hair loss, so a GP is the right first stop. WMG Meds does not prescribe to anyone under 18.

From 18 to the mid twenties

The licence is for men with male pattern hair loss. It does not set a minimum age above 18. In practice, a hairline that is changing in your late teens or early twenties may be a maturing hairline rather than pattern hair loss, and the pattern may not be settled; see mature or receding hairline and hair loss in your 20s.

Whether to start earlier or wait is a decision to make with a doctor. Because finasteride carries MHRA warnings about depression, suicidal thoughts and sexual side effects that may persist after stopping, a prescriber should ask about any history of depression and explain the risks before you start; see finasteride side effects and what the MHRA says.

Over 41, and in older men

The SmPC says the clinical studies were conducted in 1,879 men aged 18 to 41. It does not state that finasteride is unsuitable over 41, and the indication covers men with male pattern hair loss without an upper age limit, but the trial evidence in older men is thinner, and a doctor will weigh your own history.

For older men, the SmPC says no dose reduction is needed, although the half-life lengthens from about 5 to 6 hours to about 8 hours in men over 70. It also matters that finasteride lowers PSA (prostate-specific antigen), the blood marker used to check the prostate: the SmPC says doubling the PSA level should be considered before a result is evaluated. Tell any doctor ordering a PSA test that you take finasteride; see finasteride and the PSA test. If you have urinary symptoms, you may be thinking of the 5 mg tablet, which is a different product licensed for an enlarged prostate, not hair loss; see how to take finasteride.

Women

The age discussion above applies to men. The SmPC says Propecia is contraindicated in women because of the risk in pregnancy, and the NHS says finasteride is generally not recommended for women. See can women take finasteride and, for licensed options, women and minoxidil.

Is it right for you?

Age is only one factor. A GMC-registered doctor will look at your hair loss pattern, your history and your preferences, and will tell you honestly if finasteride is not the right choice. The free online assessment is the place to start.

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Related questions

Can you take finasteride at 18?

The licence is for men with male pattern hair loss and does not set an age limit above 18, but the product information is based on trials in men aged 18 to 41. A doctor decides whether it is appropriate, and the MHRA warnings apply.

Is finasteride safe for under 18s?

It is not indicated. The SmPC says there are no data demonstrating efficacy or safety in children under 18.

Is there an upper age limit for finasteride?

The Propecia SmPC does not state one. The trials enrolled men aged 18 to 41, so there is less evidence beyond that, and a doctor will consider your individual situation.

Does finasteride affect PSA tests in older men?

Yes. It lowers PSA, and the SmPC says doubling the level should be considered before the result is evaluated. Tell the doctor who orders the test.

Do older men need a lower dose of finasteride?

No. The SmPC says a reduction in dosage in the elderly is not warranted, even though the half-life is longer in men over 70.

Sources

Facts checked against these sources on 22 October 2026. This page is general information, not personal medical advice. Read our editorial policy.

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