Can a shampoo stop hair loss?

You step out of the shower and look at the drain. Hair, again. So you start washing less often, worried that the water and lather pull out even more. And at the supermarket, you hesitate in front of an "anti-hair loss" bottle that costs three times as much as your usual shampoo. Two questions, then: does washing make your hair fall out, and can a shampoo stop it?

Does washing your hair make it fall out?

No. The French Society of Dermatology (SFD) is clear: despite a common belief, shampoo doesn't make hair loss worse. On the contrary, it recommends washing your hair whenever it needs it¹.

It adds a practical point: clean hair has more volume, which hides thinner areas from view¹. So washing less does nothing against hair loss, and your hair just looks flatter between washes.

Is there such a thing as an anti-hair loss shampoo?

According to the SFD, no shampoo really stops hair loss, whatever some labels suggest¹.

To see why, it helps to know what a shampoo is in the eyes of the law. In Europe, it's a cosmetic: a product meant to come into contact with the outer parts of the body, to clean them, perfume them, change their appearance, protect them or keep them in good condition². A cosmetic isn't a medicine. And its label isn't allowed to claim properties it doesn't have². Hence the vague words you see on so many bottles, like "strengthening" or "stimulating".

European dermatologists reviewed these "miscellaneous" products, shampoos and lotions included, in their guideline on hereditary hair loss (androgenetic alopecia). For many of them, they found no study solid enough to include, and at best one or two studies per product³. Their conclusion: no evidence-based recommendation can be given for these products³.

A telling example: a commercial shampoo combining several active ingredients was compared with a placebo in 40 people, 20 in each group. After 16 weeks, hair count had risen slightly in the shampoo group and dropped slightly in the placebo group, but the difference wasn't significant³. On a label, that kind of result can turn into "clinically tested".

What about caffeine?

It's the most heavily promoted ingredient. In the lab, on follicles taken from human scalps, caffeine made the hair shaft longer³. But a follicle in a culture dish isn't a head in the shower.

A review published in 2025 pooled 9 clinical trials with 684 participants: 4 on shampoos and 5 on leave-in products⁴. Its authors conclude that caffeine preparations applied to the scalp appear safe and effective. They also admit that most of the studies are of poor quality: 5 of the 9 got the lowest evidence rating, many had no randomisation and no comparison group, and only 2 stated how much caffeine was used⁴. In one trial, 71% of participants were satisfied with a caffeine and adenosine shampoo, against 66% with a shampoo without those two ingredients⁴.

The European guideline also notes that the studies on caffeine shampoos and lotions have methodological weaknesses³. A lead, then, not proof.

If you have dandruff

There's one situation where shampoo matters more: when the scalp is irritated. Seborrhoeic dermatitis, an inflammation of the scalp that often causes dandruff, frequently comes with hereditary hair loss and can make it worse³.

A team of dermatologists followed 150 men who had both hair loss and dandruff. For 6 months, each used one of three commercial anti-dandruff shampoos, 2 to 3 times a week⁵. The itching and flakes cleared up quickly. And at the end:

Less hair in the drain, then, but no more hair on your head⁵. The limits are real: no untreated group to compare against, men only, all with dandruff, and shedding in the wash estimated roughly rather than counted hair by hair⁵. These results say nothing about hair loss without dandruff.

If you have dandruff, the American Academy of Dermatology advises following the instructions on the bottle: some anti-dandruff shampoos need to stay on the scalp for 5 to 10 minutes before rinsing. The active ingredients it lists include zinc pyrithione, salicylic acid, sulphur, selenium sulphide, antifungals and coal tar⁶. If the dandruff doesn't clear, it recommends seeing a dermatologist⁶.

Worth knowing: in France, some antifungal shampoos are prescription-only medicines⁷. That's for a doctor to decide.

So which shampoo?

The one that suits your scalp and that you like using. A gentle shampoo, used as often as you need, does its job well: cleaning and adding volume. The price or an "anti-hair loss" label adds nothing proven.

As for habits, the SFD points out that colouring and relaxing treatments applied straight onto the roots can weaken hair¹.

When to see a doctor

If your hair loss goes on, if your parting is widening or your temples are receding, a shampoo won't replace medical advice. Hair loss can have several causes. In women, for example, the SFD says it can be useful to check iron stores and vitamin B12 levels¹. A dermatologist can make a diagnosis, and your doctor can suggest a suitable treatment.

Testing a shampoo fairly

You still want to try that bottle? Fair enough. But give yourself a way to know whether it changes anything, instead of relying on the number of hairs in the drain, which varies from one wash to the next.

Before you switch shampoo, take a first set of photos. Then the same ones every week, for several months: same room, same light, same distance, hair dry and styled the same way. Aim at your parting, the crown and the temples.

That's what Calvap does. Your previous photo shows as an overlay so you can line up in exactly the same spot, and the log notes the day you changed products. Calvap shows you whether your photos have changed. They stay on your phone, and you can show them to your dermatologist if you see one.