Finasteride and minoxidil: how they differ

You searched “balding treatment” and two names keep coming up: finasteride and minoxidil. On forums they are mentioned in the same breath, as if they were two versions of the same product. Yet they have almost nothing in common: not the mechanism, not the form, not the pharmacy rules, not the side effects.

Here is what the official leaflets, the French medicines agency (ANSM) and dermatologists say, point by point. Choosing a treatment is something you do with a doctor.

How each one works

Androgenetic alopecia, or “hereditary” hair loss, is driven by a hormone made from testosterone: dihydrotestosterone, or DHT. Under its influence, some scalp follicles shrink and produce thinner and thinner hairs.

Finasteride acts upstream. It blocks an enzyme, type II 5-alpha reductase, which converts testosterone into DHT². Less DHT in the scalp means fewer follicles shrinking³. Its first expected effect is that hair loss stabilises¹.

Topical minoxidil does not touch hormones. It stimulates growth and slows shedding, but exactly how it works is not fully understood¹. The leaflet says the same: the precise mechanism is unknown⁶. At the start, it can make more hair fall for a few weeks, as described in the shedding in the first weeks of minoxidil.

Who it is for, and in what form

Finasteride for hair loss comes as a tablet and, more recently, as a spray applied to the scalp. Both are licensed for men aged 18 to 41 with early-stage androgenetic alopecia²³. The tablet leaflet states that its efficacy has not been established for advanced hair loss or for a receding hairline at the temples², which matters if your hair loss is mostly at the temples. It is contraindicated in women and must not be used in children².

Minoxidil comes as a lotion or a foam and is used by both men and women¹. In France, the 2% solution is licensed for adults, men or women⁵; the 5% solution is for men aged 18 to 65 only⁶.

Prescription and the signed form

Minoxidil lotion is sold without a prescription⁵⁶. Finasteride is prescription-only, and in France the rules changed in 2026.

Since 16 April 2026 for a new treatment, and since 16 June 2026 for every repeat, French pharmacists only dispense finasteride tablets on presentation of a shared information form, signed by both the doctor and the patient⁴. It is valid for one year and must be renewed every year. It replaces the information document introduced in 2019⁴.

The form covers the psychiatric and sexual risks, the possibility that some effects persist after stopping, the importance of taking time to think before starting, and the need for regular medical follow-up⁴. A patient card is also being added to every pack⁴. To prepare for that appointment, you can use our list of questions to ask your doctor.

Side effects

For finasteride, two groups of effects are the subject of ANSM warnings.

Psychiatric effects: low mood, depression, anxiety, suicidal thoughts²⁴. In 2025, at the ANSM’s request, the European Medicines Agency re-evaluated the medicine and confirmed the risk of suicidal thoughts⁴. The official instruction is clear: if psychiatric symptoms appear, stop the treatment and see a doctor urgently⁴.

Sexual effects: lower sex drive, erection problems, reduced ejaculate volume². In the trials, they affected slightly more men on finasteride than on placebo in the first year.

In these trials, about 1% of men in each group stopped because of these effects². According to the French Society of Dermatology, they are reversible in two cases out of three¹. The leaflet also lists sexual effects that persist after stopping, with unknown frequency². The European S3 guideline describes these persistent complaints as “post-finasteride syndrome” and notes that a link to the drug remains hard to establish⁷.

The leaflet also lists, with unknown frequency: breast tenderness or enlargement, testicular pain, blood in the semen, infertility or poor semen quality, palpitations and allergic reactions². Cases of breast cancer have been reported in treated men, and finasteride lowers PSA, a prostate marker, which a doctor needs to know to interpret a blood test². In its trial, the spray caused fewer sexual effects than the tablet, but its leaflet lists the same possible effects as the tablet³.

For minoxidil, the known effects are mainly local: irritation, flaking, itching, redness and dryness of the scalp⁶. Hair can grow away from the treated area. More rarely, low blood pressure and chest pain⁶.

Pregnancy: different precautions

Finasteride is contraindicated in women because it can cause malformation in a male foetus¹³. A woman who is or could be pregnant must not handle broken or crushed tablets² or come into contact with the spray³. As for semen, the NHS says only very small amounts of finasteride pass into it; manufacturers still recommend a condom, though most experts consider the risk low⁸. Men on treatment must not donate blood¹.

For minoxidil, the 2% solution leaflet advises not using it during pregnancy as a precaution, and avoiding it while breastfeeding⁵. The French Society of Dermatology lists it as contraindicated in pregnancy¹.

What they have in common

Both only work while you use them¹. After stopping finasteride, the benefits start to fade around the 6th month and are gone within 9 to 12 months². After stopping minoxidil, a return to the starting point is expected within 3 to 4 months⁶.

Both also take patience. The S3 guideline sets 6 months as the minimum time to judge finasteride’s effect on shedding, and 12 months for regrowth⁷. For the details, see when to judge finasteride’s effect and when to judge minoxidil lotion.

Tracking the effect in photos

Whatever treatment you decide on with your doctor, the next question is always the same: is it making a difference? The mirror is a poor judge. Hair loss that stabilises doesn’t show from one day to the next, and bathroom lighting changes everything.

What does answer it is comparable photos: same angle, same light, same distance, once a week. Calvap overlays your previous photo as a ghost so you can line up exactly the same position, and places your photos on a timeline alongside your treatment journal. You can note how you feel there too, mood included. At your follow-up appointment, you bring dated facts.