Hair Loss

Does Finasteride Work for Hair Loss? Results, Safety & Risks

By Dr Suhail Alam

February 24, 2026
Reading Time: 10 Mins

Finasteride 1 mg taken once daily is a prescription oral medication used to treat male pattern hair loss, also known as androgenetic alopecia.

It works by lowering levels of dihydrotestosterone, the hormone responsible for shrinking hair follicles in genetically susceptible men. Clinical trials show that finasteride slows hair loss and increases hair count in many men when taken consistently. Visible improvement typically begins within 6 to 12 months. Continued use is required to maintain results. Finasteride is generally well tolerated but can cause sexual or mood-related side effects in a small proportion of users, so medical supervision is essential.

Key Takeaways

Finasteride inhibits 5-alpha-reductase, lowering scalp DHT by roughly 70% and slowing hormone-driven follicle miniaturisation in male pattern baldness.
Clinical trials show significant hair count increases versus placebo, improving total hair density and active growth phase ratios.
Sexual or mood-related side effects affect a small percentage of users, highlighting the importance of informed medical supervision.

What Is Finasteride?

Finasteride is a 5 alpha reductase inhibitor. It blocks the Type II 5 alpha reductase enzyme, which converts testosterone into dihydrotestosterone, commonly referred to as DHT.

It is licensed at:

1 mg daily for male pattern hair loss
5 mg daily for benign prostatic hyperplasia

Finasteride for hair loss is a prescription-only medicine in the UK and many other countries.

How Finasteride Works for Hair Loss

Male pattern hair loss occurs when DHT binds to androgen receptors within scalp hair follicles. Over time, this shortens the hair growth phase and causes follicles to become smaller. The hair produced becomes finer and shorter until growth may stop completely.

Finasteride lowers DHT levels in the scalp and bloodstream. By reducing DHT exposure:

The rate of follicle miniaturisation slows
Existing hairs may increase in thickness
Hair density may improve

Finasteride targets the hormonal cause of androgenetic alopecia rather than stimulating growth directly.

Effectiveness and What to Expect

Clinical Evidence

In large randomised trials, finasteride 1 mg daily significantly slowed hair loss and produced measurable increases in scalp hair counts versus placebo over 1–2 years. In these studies, treated men showed more new and thicker hairs at points like the crown than those on placebo.

Review articles confirm finasteride’s effectiveness compared with untreated progression and note hair count improvements sustained with continuous use.

Timeline of Results

3–6 months: Hair loss often stabilises; some early thickening may begin.
6–12 months: Visible improvements in density for many users.
12–24 months: Peak improvements typically observed; continued daily use needed to maintain gains.

Consistent use is key: stopping finasteride usually leads to loss of gains and a resumption of previous hair loss patterns within a few months.

Studies report that up to around 80–90% of men see reduced hair loss or better density with finasteride.

Who Is Finasteride For?

Finasteride is suitable for:

Adult men with confirmed androgenetic alopecia
Men experiencing thinning at the crown or early frontal recession
Individuals seeking to slow further hair loss

It is most effective when started earlier in the course of hair loss.

Who should not take it

Finasteride is not recommended for:

Women who are, or may become, pregnant (risk of birth defects).
Children and adolescents.
Individuals with known hypersensitivity to finasteride.
People with significant liver impairment or conditions that complicate hormone therapies.

Women of childbearing potential must not handle crushed or broken tablets due to risk of harm to a male foetus.

Response may vary by age and severity. Men with advanced hair loss may experience stabilisation rather than significant regrowth.

Dosage and Administration

Standard dose for hair loss is 1 mg taken orally once daily.

How to take it:

Take at the same time each day
May be taken with or without food
Swallow tablet whole

If a dose is missed, take the next scheduled dose. Do not double the dose. Long-term, continuous use is required. Stopping treatment usually results in gradual loss of benefits.

Side Effects & Safety

Common and Less Common Effects

Finasteride is generally well-tolerated, but side effects can occur — especially affecting sexual function and mood.

Sexual side effects may include:

Reduced libido.
Difficulty with erections.
Change in ejaculation.

These effects are uncommon but recognised side effects, occurring at a higher rate than placebo in some studies.

Psychiatric Considerations

Regulators have issued warnings that psychiatric side effects — including depression and, in rare cases, suicidal thoughts — have been reported in men taking finasteride. Updated product packaging in the EU and UK will include patient alert cards to raise awareness of these potential effects and the importance of prompt medical review if they occur.

Reversibility

Many side effects resolve after stopping the drug, but rare cases are reported where symptoms persist beyond discontinuation. Clinicians should counsel potential users about this and perform appropriate monitoring.

Interactions and Precautions

There are no major common drug interactions, but finasteride is contraindicated in women of childbearing potential (because of serious teratogenic risk) and should be used with caution in individuals with hormone-related conditions. A careful medication and health history review is part of safe prescribing.

Men undergoing prostate screening should inform clinicians that they are taking finasteride, as it lowers PSA values used in prostate cancer screening.

Monitoring & Follow-Up

Before treatment: Full medical and medication history, discussion of benefits and risks, assessment of hair loss pattern.
Early checks: Around 3–6 months to assess adherence, side effects, and initial response.
Ongoing review: Annually or as clinically indicated.

If persistent or concerning side effects develop, a clinician may consider dose adjustment, alternative therapies, or stopping treatment.

Comparisons With Other Hair Loss Treatments

Many clinicians recommend combination therapy (finasteride plus minoxidil) to maximise outcomes because one tackles hormonal decline and the other stimulates growth.

Treatment	Mechanism	Prevents Hair Loss	Regrowth Chance
Finasteride (1 mg)	DHT inhibition	Yes	Moderate
Topical minoxidil	Follicle stimulation	Partial	Yes
Dutasteride (off-label)	Broader DHT inhibition	Yes (stronger)	Often greater than finasteride
Hair transplant	Surgical relocation	No (needs meds adjunct)	Yes

What to Tell Your Healthcare Provider Before Taking Finasteride

Tell your healthcare provider if you:

Have liver disease
Have a history of depression or other mental health conditions
Have sexual dysfunction
Are trying to conceive
Have prostate conditions or are undergoing PSA testing
Have had an allergic reaction to finasteride

Tell your provider about all medicines, supplements or herbal products you are taking.

Women who are pregnant or may become pregnant must not take this medicine or handle crushed or broken tablets.

Conclusion

Finasteride slows DHT-driven hair loss and helps maintain density when used consistently. Earlier treatment often produces better outcomes because more follicles remain viable, making timely assessment important.

Medical consultation ensures suitability and realistic expectations. If you are noticing progressive thinning, book a free consultation, and we’ll help determine whether finasteride suits your needs and treatment goals.

FAQs

How long does finasteride take to work for hair loss?

Visible improvements typically appear at 6 to 12 months with peak benefits occurring around 12 to 24 months of consistent daily use. Early changes involve shedding stabilisation within 3 to 6 months.

Will hair loss return after stopping finasteride?

Yes, hair loss resumes within 3 to 6 months of discontinuation because DHT levels return to baseline and follicle miniaturisation restarts. Finasteride manages hair loss rather than curing it permanently.

Is finasteride safe for long-term use?

Long-term safety data spanning decades shows finasteride remains well-tolerated with continued use. Annual medical review ensures ongoing appropriateness and monitors for any delayed effects.

Can finasteride affect fertility or mood?

Fertility effects are minimal in clinical studies, though reduced semen volume occurs in some users without affecting sperm function. Mood changes affect fewer than 1% of users but warrant monitoring.

Can women use finasteride for thinning hair?

Women of childbearing potential should not use finasteride because of birth defect risks. Postmenopausal women occasionally use it off-label under strict medical supervision with informed consent.