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Finasteride is a daily 1 mg tablet, and one of the few hair-loss medicines formally authorised for this purpose in EU countries. It works by lowering DHT, a hormone made from testosterone that gradually shrinks hair follicles in male pattern hair loss. It is authorised for men only, and it is not for women.

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What it is

Finasteride is a 5-alpha-reductase inhibitor — specifically a 4-azasteroid 5-alpha-reductase inhibitor, taken as a 1 mg film-coated tablet. It reduces the conversion of testosterone into DHT, the hormone responsible for follicle miniaturisation in male androgenetic alopecia.
Active ingredient: finasteride. Dosage: 1 mg once daily, with or without food. It is a continuous daily treatment — on discontinuation, effects fade over 6–12 months.

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How it works

DHT shrinks the hair follicle

Male pattern hair loss is driven by dihydrotestosterone (DHT), a hormone the body makes from testosterone. A balding scalp contains miniaturised follicles and higher amounts of DHT, so each growth cycle produces a thinner, shorter hair until visible growth stops.

Finasteride blocks the converting enzyme

It blocks the type II 5-alpha-reductase enzyme that turns testosterone into DHT, so less DHT reaches the scalp.

Scalp DHT falls, follicles recover

With less DHT reaching the scalp, the miniaturisation process is opposed and follicles can recover over time.

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EU authorisation

Finasteride has been authorised for use in the EU since 1 February 1999 (AEMPS CIMA, Propecia 1 mg film-coated tablets, Spain registration 62441), so a licensed doctor can prescribe it when it is clinically appropriate.

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What the studies reported

The trials behind finasteride (Kaufman et al., J Am Acad Dermatol 1998, PMID 9777765) enrolled only men aged 18–41 with vertex-pattern hair loss. They did not establish an effect on bitemporal recession or late-stage hair loss, and the EU product information states that continued use is needed to keep the benefit.

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What has been reported

The figures below compare finasteride 1 mg with placebo, as reported in the EU Summary of Product Characteristics (SmPC, section 4.8). About 1% of men in each group (finasteride and placebo) stopped treatment for a sexual side effect in the first 12 months.
Persistence of decreased libido, erectile dysfunction and ejaculation disorders after finasteride is stopped has been reported in post-marketing use. Frequency is not known, because these are spontaneous reports.
Depression is listed as uncommon; anxiety and suicidal ideation are listed with frequency not known. After an EU-wide Article 31 review (started October 2024, European Commission decision August 2025), suicidal ideation was confirmed as a side effect of finasteride 1 mg and 5 mg tablets at an unknown frequency, and a patient card is now included in 1 mg packs. Anyone who experiences mood changes should seek medical advice and, on finasteride 1 mg, stop treatment.
Reported during post-marketing use; frequency cannot be estimated from the available data.
The EU product information contraindicates use in women, because finasteride can cause abnormalities of the external genitalia in a male foetus if taken during pregnancy.

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A steady, monitored routine

1

Months 1–3

Daily 1 mg tablet; changes build silently.
2

Months 3–6

Shedding stabilises.
3

Months 6–12

Visible improvement is assessed.
4

Ongoing

Continuous use with periodic reviews.

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Who it is not suitable for

Finasteride is authorised for adult men with male pattern hair loss only — it is not authorised for women or people under 18.

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How Hi-Doctor handles it

A licensed doctor confirms the diagnosis, reviews the risks, and rules out contraindications before prescribing. The medicine itself is paid separately at a pharmacy; the pricing page covers what the consultation fee includes.

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Sources

  • AEMPS CIMA — Propecia 1 mg comprimidos recubiertos, ficha técnica (Spain, registration 62441, authorised 1 February 1999)
  • emc — Propecia 1 mg Film-Coated Tablets, Summary of Product Characteristics
  • EMA — Article 31 referral: finasteride- and dutasteride-containing medicinal products
  • Kaufman et al., J Am Acad Dermatol 1998 (PMID 9777765)

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Answer the hair-growth questionnaire and a registered doctor reviews it. They decide whether treatment is appropriate, which one, and at what dose — and declining is a normal outcome. See what it costs and how the review works.
This page is reference information, not medical advice and not a prescription. Whether a medicine is appropriate for you is decided by a registered doctor after reviewing your consultation.