> ## 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.
# Side effects: hair-loss medicines
> Reported side effects of finasteride, minoxidil and dutasteride, with placebo comparators where they exist, and the EU regulatory warnings that apply.
Hair-loss treatment is long-term, so its side effects matter more than they
would for a short course. Some of the medicines used for hair loss in Europe are
authorised for that purpose; several are not, and are prescribed off-label or
not at all. That distinction changes how much is known about their risks.
## Finasteride
Finasteride is a daily 1 mg tablet and one of the few hair-loss medicines
formally authorised for this purpose in EU countries. It is authorised for men
only, and it is not for women.
| Reported effect | Finasteride 1 mg | Placebo |
| ------------------------------------------------------ | ---------------- | ------- |
| Drug-related sexual adverse reactions, first 12 months | 3.8% | 2.1% |
| Decreased libido | 1.8% | 1.3% |
| Erectile dysfunction | 1.3% | 0.7% |
| Decreased ejaculate volume | 0.8% | 0.4% |
In the phase III trials the overall sexual adverse reaction rate fell to 0.6%
over the following four years. About 1% of men in each group stopped treatment
for this reason in the first 12 months (EU SmPC, section 4.8). Decreased libido,
erectile dysfunction and ejaculation disorder are each classified as **uncommon**
(1 in 1,000 to 1 in 100) in the EU SmPC.
**Mood.** 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.
Two further points from the EU product information:
* **Persistence after stopping.** 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.
* **Contraindicated in women.** Finasteride can cause abnormalities of the
external genitalia in a male foetus if taken during pregnancy.
Male breast cancer has been reported during post-marketing use; frequency cannot
be estimated from the available data.
## Minoxidil
Minoxidil comes in two very different forms and the difference matters. The
liquid or foam rubbed into the scalp is an authorised medicine for male pattern
hair loss in EU countries. Minoxidil tablets also exist, but in the EU those are
licensed **only** as a blood-pressure medicine, so taking low-dose minoxidil
tablets for hair is off-label.
### Topical minoxidil
There is no placebo column here — the EU product information records these by
frequency band rather than against a comparator.
| Reported effect | EU frequency |
| ----------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------- |
| Itching, dermatitis, acneiform dermatitis and rash — application-site reactions can occasionally be more severe and include peeling, blistering, bleeding or ulceration | Common |
| Unwanted hair growth away from the scalp (hypertrichosis), including facial hair growth in women | Common |
| Headache and dyspnoea | Common |
| Dizziness, nausea, peripheral oedema | Uncommon |
| Palpitations, tachycardia, chest pain | Rare |
| Low blood pressure and allergic reactions including angioedema | Frequency not known |
| Temporary hair loss | Frequency not known |
### Low-dose oral minoxidil, used off-label
In a 24-week randomised trial of oral minoxidil 5 mg versus topical minoxidil 5%
(n=45 per arm):
| Reported effect | Oral 5 mg | Topical 5% |
| --------------- | ----------- | ----------- |
| Hypertrichosis | 22/45 (49%) | 11/45 (25%) |
| Headache | 6/45 (14%) | 1/45 (2%) |
| Scalp eczema | 1/45 (2%) | 7/45 (16%) |
In a retrospective multicentre study of 1,404 patients treated for at least
3 months, the most frequent adverse effect was hypertrichosis (15.1%, causing
withdrawal in 0.5%). Systemic effects were lightheadedness 1.7%, fluid retention
1.3%, tachycardia 0.9%, headache 0.4%, periorbital oedema 0.3% and insomnia
0.2%, leading to discontinuation in 1.2% of patients.
EU-authorised minoxidil tablets are indicated only for severe resistant high
blood pressure, and their product information states they must never be used
alone or as initial therapy — always alongside a beta-blocker and a diuretic.
None of that licensed dosing framework applies to the low doses used off-label
for hair loss, which is why the doctor monitors blood pressure.
## Dutasteride
Dutasteride is authorised in the EU for an enlarged prostate, not for hair loss;
using it for hair loss in Europe is off-label. The figures below come from
placebo-controlled phase III **prostate** trials in older men taking 0.5 mg, not
from hair-loss trials.
| Reported effect | Year 1 (n=2,167) | Year 2 (n=1,744) |
| ------------------------------------------------- | ---------------- | ---------------- |
| Impotence | 6.0% | 1.7% |
| Decreased libido | 3.7% | 0.6% |
| Ejaculation disorders, incl. reduced semen volume | 1.8% | 0.5% |
| Breast disorders (tenderness, enlargement) | 1.3% | 1.3% |
The EU product information states that these sexual adverse events are
associated with dutasteride treatment, that they may persist after treatment is
stopped, and that the role of dutasteride in that persistence is not known.
Depression is listed with frequency not known. Following the EU Article 31
review concluded in 2025, information about the mood changes seen with
finasteride is being added to dutasteride product information as a precaution,
because dutasteride works in the same way; a direct link between dutasteride and
suicidal ideation was not established. Alopecia (mainly loss of body hair) and
hypertrichosis are listed as uncommon.
## Two medicines Hi-Doctor does not prescribe for hair
Authorised in EU countries for high blood pressure, some types of heart
failure and excess aldosterone — not for hair loss anywhere in the EU. In a
pooled analysis of five studies (413 patients), scalp itching or flaking was
reported in 18.9% of women, menstrual changes in 11.9% and facial hair
growth in 6.9%. Those five studies were mostly observational, used doses
from 25 to 200 mg over six months to over a year, and none compared
spironolactone against a placebo, so the figures cannot be separated from
natural variation or from other treatments taken at the same time.
An antifungal. In the EU the shampoo, cream and gel are authorised for
dandruff, seborrhoeic dermatitis and pityriasis versicolor. The Spanish
product information for topical ketoconazole 20 mg/g lists a local burning
sensation, itching, and contact dermatitis from irritation or allergy, and
records oily or dry hair as rare along with rare discolouration of
chemically damaged or grey hair. The oral form was suspended EU-wide — CHMP
recommendation 25 July 2013, European Commission decision 11 October 2013 —
because the risk of liver injury outweighed the benefit. Topical forms were
not suspended.
## Contact your doctor if
* you have persistent side effects that concern you — sexual, mood changes,
breast tenderness or enlargement
* you notice a breast lump or nipple discharge, or severe low mood
* a scalp reaction does not improve, or you have a severe scalp reaction, facial
swelling or breathing difficulty
* you have chest pain, a fast heartbeat, faintness, sudden weight gain, or
swelling of hands or feet while on oral minoxidil
* there is no visible improvement after 12 months of consistent use
Related: [finasteride](/library/medicines/finasteride) ·
[minoxidil](/library/medicines/minoxidil) ·
[dutasteride](/library/medicines/dutasteride) ·
[what to expect in the first month](/library/guides/what-to-expect-first-month) ·
[Safety](/essentials/safety)
## 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.