> ## Documentation Index
> Fetch the complete documentation index at: https://docs.hi-doctor.ai/llms.txt
> Use this file to discover all available pages before exploring further.
# Propecia
> Propecia (finasteride 1mg): how it lowers DHT, its national EU authorisation, sexual side-effect rates, and the 2025 mood-safety update.
Finasteride is a daily 1 mg tablet, and it is 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, and it is authorised for men only.
## What it is
Propecia contains the active ingredient finasteride, a 4-azasteroid 5-alpha-reductase inhibitor, taken as a 1 mg film-coated tablet, with or without food, once a day. Propecia holds national authorisations rather than a single EU-wide one; the details here come from the Spanish authorisation (AEMPS CIMA registration 62441, holder Organon Salud, S.L.), authorised since 1 February 1999. The authorised age band is narrow — men aged 18 to 41 with androgenetic alopecia — and it is not authorised for use in women.
Active ingredient: **finasteride**. Dosage: **1 mg / day**.
## How it works
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 5-alpha-reductase type II enzyme that converts testosterone into DHT, so less DHT reaches the scalp.
Daily 1 mg; changes build silently.
Shedding stabilises.
Visible improvement is assessed.
## What the studies reported
The trials enrolled only men aged 18–41 with vertex-pattern loss (Kaufman et al., *J Am Acad Dermatol* 1998, PMID 9777765), and did not establish an effect on bitemporal recession or late-stage hair loss. The EU product information states continued use is needed to keep the benefit.
## What has been reported
| Reaction | Finasteride 1 mg | Placebo | EU SmPC classification |
| ---------------------------------------------------- | ---------------- | ------- | --------------------------------- |
| Sexual adverse reactions overall (first 12 months) | 3.8% | 2.1% | — |
| Sexual adverse reactions overall (following 4 years) | 0.6% | — | — |
| Decreased libido | 1.8% | 1.3% | Uncommon (1 in 1,000 to 1 in 100) |
| Erectile dysfunction | 1.3% | 0.7% | Uncommon (1 in 1,000 to 1 in 100) |
| Ejaculation disorder (decreased ejaculate volume) | 0.8% | 0.4% | Uncommon |
About 1% of men in each group stopped treatment for a sexual side effect in the first 12 months (EU SmPC, section 4.8). Persistence of decreased libido, erectile dysfunction and ejaculation disorders after finasteride is stopped has been reported in post-marketing use, at a frequency that is not known because these are spontaneous reports. Male breast cancer has been reported during post-marketing use; frequency cannot be estimated from the available data.
**Mood and suicidal ideation.** Depression is listed as uncommon in the EU SmPC; anxiety and suicidal ideation are listed at a frequency that is 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.
## Who it is not suitable for
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. The authorised age band is men aged 18 to 41.
Female hair loss sometimes involves finasteride prescribed off-label, at a different dose and under different safeguards. See the [finasteride for female hair loss guide](/library/guides/female-finasteride).
## How Hi-Doctor handles it
Our doctors review every hair-growth option and recommend what fits your history and goals. An EU-licensed doctor reviews your case and, if eligible, issues an electronic prescription valid at any EU pharmacy under Directive 2011/24/EU. See [how it works](/essentials/how-it-works) for the full process, [pricing](/essentials/pricing) for the consultation fee, and [topical minoxidil](/library/medicines/topical-minoxidil) for another EU-authorised hair-growth option.
## Start a consultation
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](/essentials/pricing)
and [how the review works](/essentials/how-it-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.