Hair loss serum or medicine?

At the pharmacy, two bottles sit side by side. Same dropper, same “anti-hair loss” on the label, similar prices. One is a medicine, the other a cosmetic. In law, they have almost nothing in common: the first had to prove it works before reaching the shelf, the second didn’t ask anyone’s permission.

Knowing which one you’re holding changes what you can expect from it. It’s written on the packaging, as long as you know where to look. This article follows French and EU law.

What makes a medicine

The French Public Health Code defines a medicine in two ways¹. First, it’s any product presented as curing or preventing a disease. What it contains doesn’t matter: the promise is what counts. Second, it’s any product that restores, corrects or modifies a bodily function through a pharmacological, immunological or metabolic action, in other words one that actually acts on how the body works.

The same article adds a rule of caution: when a product could fit both the definition of a medicine and that of another category, it is treated as a medicine whenever there is doubt¹.

A medicine can only be sold once it has a marketing authorisation. The ANSM, the French medicines agency, bases it on weighing up benefits against risks². The manufacturer has to show the product works for specific indications, describe its side effects and how often they occur, and prove the quality of its manufacturing. The authorisation is granted by the ANSM or the European Commission, with two documents: the summary of product characteristics for health professionals, and the patient leaflet for you².

What makes a cosmetic

A cosmetic, in the definition the ANSM uses, is a product applied to the outer parts of the body, hair included, to clean them, perfume them, change their appearance, protect them, keep them in good condition or correct body odour³. A scalp serum, a “strengthening” lotion or a shampoo for hair loss all fit this description.

Here is the big difference: there is no prior authorisation to put a cosmetic on the market³. Nobody signs off on the product before it reaches the shelf. It’s up to the manufacturer to make sure it complies with the law and is safe for health. EU regulation requires a “responsible person” to be named, with their name and address on the packaging⁴.

Checks come afterwards. The ANSM monitors the market together with the DGCCRF, the French consumer protection authority, and runs a vigilance system to spot side effects once products are on sale³.

“Anti-hair loss”: where the line falls

A product for hair loss can land on either side. To settle these borderline cases, experts from the member states and the European Commission wrote a manual. It isn’t legally binding, but it exists so that every country applies the rules the same way⁵. On products that stimulate growth or reduce hair loss, it says three things.

First, each case is judged on its own. The question is whether the product changes how the follicle works through a pharmacological action. Concentration, absorption, how often it’s applied, how far it penetrates the skin: all of it counts⁵.

Second, an ingredient also being used in a medicine isn’t enough to make the serum a medicine. It’s a clue, not proof⁵.

Third, the wording on the pack is a useful pointer. A promise to make hair grow usually points to a medicine. A promise to reduce hair loss usually points to a cosmetic, and a product that prevents hair fall can be a cosmetic too⁵. The manual gives an example: minoxidil, found in lotions sold as medicines, is banned as a cosmetic ingredient. So a cosmetic serum can’t contain it.

What a serum is allowed to claim

The EU Cosmetics Regulation sets the principle: text, names, trade marks and pictures can’t attribute to a product characteristics or functions it doesn’t have⁴. A 2013 regulation lays down six criteria every claim must meet, including claims made through a picture, a range name or a brand⁶. Four rules matter to you directly.

• Every claim, even an implied one, must rest on adequate, verifiable evidence: studies on the product and on the claimed effect, using sound methods⁶.
• The promised effect can’t go beyond what that evidence shows⁶.
• Praising an ingredient mustn’t suggest the finished product has the same properties if it doesn’t⁶.
• A cosmetic can’t say it’s authorised or approved by an EU authority, or present as a selling point something every product is required to do⁶.

And one limit doesn’t move: as soon as a product presents itself as treating or preventing a disease, it falls within the definition of a medicine¹. A cosmetic that said “treats alopecia” would be out of its lane.

How good is the evidence?

“Clinically tested” on its own doesn’t tell you how many people, for how long, or what was measured. To get an idea of the real level of evidence, you have to look at published research.

In 2024, a Canadian team reviewed non-prescription products for hereditary hair loss, known as androgenetic alopecia⁷. Out of 903 articles found in scientific databases, they kept only trials with a comparison group and an assessor who didn’t know who was getting what. That left 13, covering eight ingredients, including caffeine and rosemary oil.

Review by Gupta et al., Skin Appendage Disorders, 2025⁷

These trials show gains in hair density or thickness compared with a placebo. But they are small, often a few dozen participants, and no ingredient proved more effective than the standard treatments⁷. The authors call for larger, longer trials. One more limit: the review looks at ingredients tested on their own, not at the serums on sale, which often mix several.

Reading the label

A medicine comes with a patient leaflet in the box. In France, you can also type its name into the public medicines database, run by the ANSM with the French health authority and national health insurance. It lists the medicines sold in France over the last three years, with their official information⁸.

For a cosmetic, EU law requires the packaging to show⁴:

• the name and address of the responsible person;
• the product’s function, unless it’s obvious;
• the ingredient list, headed by the word “ingredients”;
• a use-by date, or how long it keeps once opened;
• precautions for use and a batch number.

Then read the promise word by word. “Reduces hair loss”, “helps limit hair fall”, “stronger hair”: that’s cosmetic vocabulary. “Regrows hair” usually belongs to medicines⁵. If a bottle with no leaflet promises regrowth, ask yourself what evidence it rests on. Look at the full ingredient list rather than the star ingredient on the front: that’s what tells you what you’re putting on your scalp, just like what’s inside a capsule.

Judge your serum on the evidence

Cosmetic or medicine, a hair product is judged over months. The trials in the Canadian review lasted from 16 weeks to 6 months⁷. The mirror, meanwhile, changes its mind every morning depending on the light.

With Calvap, you take the same photo every week, in the same spot, guided by a ghost of last week’s photo. You log the day you start your serum in the journal. After a few months, you compare zone by zone: part, crown, temples. You see what your serum has changed for you, not for the participants in a study. And if the shedding carries on, you can show dated photos to the right doctor, who can suggest a treatment.