Male pattern baldness: assessment, treatments, evidence

What happens under the scalp

Common baldness, or androgenetic alopecia, affects up to 80% of men of European origin. It depends on genes and on dihydrotestosterone (DHT), a hormone made from testosterone by an enzyme, 5-alpha reductase.

In predisposed men, DHT shortens the growth phase: cycle after cycle, the follicle shrinks (this is miniaturisation) and the hair becomes thin, like down. The Hamilton-Norwood scale describes the progression in seven stages: the temples recede first, then the crown thins.

The assessment: making sure it really is baldness

The diagnosis is mostly clinical: pattern of the loss, pull test, dermatoscope (an illuminated magnifier), examination of the beard, eyebrows and nails. To be told apart:

• Alopecia areata: round, smooth patches that appear quickly, sometimes in the beard.
• Telogen effluvium: sudden, diffuse shedding two to three months after a fever, an operation, a diet or major stress.
• A deficiency, particularly in iron, or a thyroid disorder.
• A medicine, or the use of testosterone or anabolic steroids.
• More rarely, scarring alopecia: a red, painful or shiny scalp.

A blood test is not routine: European guidelines reserve it for cases where the examination does not rule out another cause; we then measure, for example, ferritin (iron) and TSH (thyroid).

Minoxidil lotion or foam

It is a first-line treatment, superior to placebo in meta-analyses and recommended by the European Dermatology Forum (EDF) for mild to moderate stages: 1 ml of 2% or 5% solution (5% is suggested in men), or half a capful of 5% foam, twice a day on a dry scalp.

The effect appears within three to six months. Increased shedding may occur in the first weeks: resting hairs are re-entering the growth phase, and you should not stop. When treatment stops, hair loss resumes after about three months. Side effects are mainly local: itching, redness, eczema, sometimes hair growth on the face; applying it at least two hours before bedtime limits this risk.

Finasteride: effective, but its safety is debated

It blocks type 2 5-alpha reductase and lowers DHT by about two thirds. At 1 mg a day, recommended by the EDF in 2018, it slows hair loss and increases hair count compared with placebo; the effect on hair loss is judged at six months, regrowth at one year.

Its best-known side effects are sexual: reduced desire, erection or ejaculation problems, in about 2 to 6% of men in trials. Problems persisting after stopping have been reported, with a debated link. A woman who is pregnant, or may become pregnant, must not handle the tablets.

In May 2025, the European pharmacovigilance committee (PRAC) confirmed that suicidal ideation is a side effect of finasteride 1 mg and 5 mg tablets, with an unknown frequency. It considers that the benefits still outweigh the risks in the authorised indications, subject to measures: stop finasteride 1 mg and seek medical advice if mood changes occur, seek medical advice for sexual problems, and a patient card in the packs. This position, adopted by majority, has been final since August 2025.

Belgium, like France, expressed a divergent opinion. The 1 mg tablet has never been authorised in Belgium: it is prescribed off-label, as a pharmacy-compounded preparation. For the Belgian medicines agency (FAMHP), as for the Belgian Centre for Pharmacotherapeutic Information, its risks are not outweighed by its benefits in baldness. For finasteride spray, available in Belgium since 2025, the PRAC found no evidence of a link with suicidal ideation. This spray is nevertheless partly absorbed into the blood: pregnant women and children must avoid any contact with the treated scalp.

So I only discuss finasteride case by case, after a thorough discussion. It is contraindicated in case of current depression or sexual dysfunction.

Low-dose oral minoxidil

Developed for high blood pressure, oral minoxidil is used off-label for hair loss, at low doses (often 1.25 to 5 mg a day in men). The data diverge: a network meta-analysis ranks it among the most effective options at six months; another, of four comparative trials (279 patients), finds no difference in density compared with the lotion.

More often than with the lotion, it causes hair growth elsewhere than on the scalp (in about one patient in four). Temporary shedding at the start and swollen ankles are possible; fluid around the heart is rare. Contraindications: pericardial disease, poorly controlled high blood pressure. I check your blood pressure and pulse.

Dutasteride

At 0.5 mg a day, dutasteride increases hair count slightly more than finasteride at six months. But in Belgium, as in the European Union, it is authorised only for benign prostatic hyperplasia: in baldness, its use is off-label, and the EDF only considers it after one year of finasteride failure. Its sexual side effects are similar; for suicidal ideation, no link has been established, but a warning has been added as a precaution.

PRP: an add-on with a modest benefit

A concentrate of your own platelets is injected into the scalp. Protocols vary widely, and in 2018 the EDF made no recommendation for or against it. A meta-analysis of nine randomised trials (238 patients) shows increased density compared with placebo at three and six months, but no clear effect on hair count or diameter: the benefit is modest. It is a possible add-on, not a substitute.

What about a hair transplant?

A transplant moves follicles from the back of the head, which are not very sensitive to DHT, to thinning areas, without stopping the progression of the remaining hair. It is another approach, which I do not perform at the practice: we can talk it over together.

Judging the effect: standardised photographs

The mirror is misleading: I take standardised photographs at the start, at six months and at one year (same lighting, same angles). For the EDF, this is the most reliable method to assess hair growth. Stabilising hair loss is already a result; partial regrowth is possible, never guaranteed.