Male hair loss: causes and what is proven to work

How hereditary hair loss develops

Androgenetic alopecia is not a disease in the narrow sense but a genetically determined reaction of hair follicles to male hormones. In the follicles at forehead and crown the enzyme 5-alpha reductase converts testosterone into dihydrotestosterone. With the corresponding predisposition, this hormone shortens the growth phase of the hair from several years to months and shrinks the follicle. Strong terminal hair becomes fine, short vellus hair until the follicle finally falls silent. The rim of hair at the back and sides is spared because its follicles are insensitive; that is why hair transplants work.

Testosterone levels themselves are normal in men with hair loss. It is the sensitivity of the follicles that is inherited, via many genes and from both parents, not only from the maternal grandfather as is often claimed. About every second man is affected at 50, four in five at 70. A quarter show first signs before the age of 30. The course is individual: some men lose a lot in a few years, others keep a thin but stable hair pattern for decades.

Is it really hereditary hair loss?

The pattern reveals the cause. A receding hairline, retreating temples and a thinning crown while the rim of hair remains, graded on the Hamilton-Norwood scale, are typical of androgenetic alopecia. The doctor usually recognises it by looking at scalp and distribution, if needed with a magnified examination that shows the difference between strong and shrunken hairs.

Other causes look different:

Cause	Pattern	Typical clues
Telogen effluvium	diffuse over the whole head	begins 2 to 3 months after fever, surgery, crash diet, severe stress; usually regrows
Alopecia areata	sharply defined round patches	often sudden, also beard and eyebrows, autoimmune disease
Deficiency and metabolism	diffuse	low ferritin, thyroid dysfunction, vitamin D deficiency, zinc deficiency
Medicines	diffuse	anticoagulants, retinoids, chemotherapy, some antidepressants, high-dose vitamin A
Scalp diseases	patchy, with scaling, redness or scarring	fungal infection, lichen planopilaris, discoid lupus; belong in dermatology

With diffuse hair loss or an unusual course, laboratory values are sensible: ferritin, thyroid values, if needed vitamin D, zinc and blood count. With the typical pattern no blood test is needed.

What is proven to work

The European S3 guideline on androgenetic alopecia rates the available treatments by the quality of the studies. Two substances receive the strongest recommendation.

Finasteride

Finasteride inhibits 5-alpha reductase and lowers dihydrotestosterone in the scalp by around two thirds. In the approval trial by Kaufman and colleagues with 1,553 men aged 18 to 41, after two years 83 percent on finasteride 1 mg showed no further hair loss, on placebo 28 percent; 66 percent had visibly more hair, on placebo 7 percent. Long-term data over five years confirm the sustained effect as long as intake continues.

Side effects mainly concern sexual function: reduced libido, erection problems and lower ejaculate volume in about 4 percent compared with around 2 percent on placebo; in most men they subside while continuing or after stopping. Persistent symptoms after stopping have been reported; they are rare and their frequency disputed. Rarer are breast tenderness and mood changes. In 2025 the German Federal Institute for Drugs and Medical Devices warned in a safety letter of suicidal thoughts and behaviour as a possible side effect; the European Medicines Agency has updated the product information accordingly. Anyone who notices a mood change on finasteride stops and speaks to a doctor. With a history of depression the decision must be weighed particularly carefully. Finasteride lowers the PSA value by about half; this must be known for later prostate screening. Women of childbearing age must not touch broken tablets because the substance can harm an unborn child.

Minoxidil

Minoxidil prolongs the growth phase and improves blood flow to the follicle; the exact mechanism is not fully understood according to the review by Suchonwanit and colleagues. The 5 percent solution or foam is applied twice daily to the dry scalp and works better than the 2 percent form. Side effects are itching, scaling and, with the solution, irritation from the carrier; the foam is better tolerated. In the first weeks hair loss may temporarily increase because resting hairs are shed. Minoxidil is available without prescription in Germany.

Low-dose oral minoxidil is increasingly used but is not approved for this indication and belongs under medical supervision because of possible effects on blood pressure and heart.

Combination and duration

The guideline recommends the combination of finasteride and minoxidil for pronounced loss because both act at different points and achieve more together. Realistic expectations: stabilisation after three to six months, thickening after six to twelve. Lost follicles do not come back; the earlier treatment starts, the more hair is preserved. After stopping, the gain is lost within six to twelve months.

What helps only to a limited extent or not at all

Platelet-rich plasma (PRP) and low-level laser therapy showed moderate improvements in smaller studies; the guideline sees them as possible additions. Ketoconazole shampoo can improve accompanying scalp inflammation but does not replace therapy. Caffeine shampoos have weak evidence. Biotin helps only with a proven deficiency, which is rare with a normal diet; high doses distort laboratory values, for example of the thyroid and the cardiac marker troponin. Supplements with zinc, selenium, millet or saw palmetto have no proven effect on hereditary hair loss. Dutasteride inhibits both forms of 5-alpha reductase and is somewhat stronger than finasteride but is not approved for hair loss in Germany.

Hair transplantation

With advanced loss and a stabilised course, a transplant can permanently relocate your own hair from the rim to forehead and crown; the follicles keep their insensitivity. Follicular unit extraction leaves no visible scar. Important are realistic planning of the hairline that takes the further natural course into account, and continuing finasteride or minoxidil so that the non-transplanted hair is preserved. A transplant is a cosmetic operation with risks and costs; independent medical advice beforehand is worthwhile.

What the video consultation can do

The hair pattern can be assessed well by video and with good photos of hairline, crown and back of the head. The doctor asks about onset and course, family history, pre-existing conditions, medicines, mood, plans for children and expectations, rules out other causes and discusses the benefits and risks of the options. If suitable, they issue a private prescription for finasteride; minoxidil is available without prescription. With diffuse loss, scalp changes or an unclear picture, the recommendation is laboratory tests or dermatology.

German statutory health insurers do not reimburse hair loss treatments (section 34 SGB V). The medical service at OpenClinic24 is billed under the GOÄ fee schedule, with every item on the invoice.

Hair loss in women

Women also experience hereditary hair loss, usually as diffuse thinning at the crown with a preserved hairline, often after menopause. According to the Cochrane analysis by van Zuuren and colleagues, minoxidil is effective in women too; finasteride is not suitable for women of childbearing age because of the risk to an unborn child. In women, iron deficiency, thyroid disease and hormonal disorders are more often the cause and should always be checked.