Biotin and hair: what we are legally allowed to say
In a hair care aisle, biotin is everywhere. On bottles, on capsules, in advertising. Dosages run from 50 to 10,000 µg without anyone explaining why, and the promises go far beyond what regulation allows.
Here is what can be said, what cannot, and why the difference matters.
What biotin is
Biotin is a B-group vitamin — B8 in France, B7 in international nomenclature. It is the same molecule.
It is water-soluble: it dissolves in water, the body stores no reserve of it, and whatever is not used leaves in the urine. That is an important difference from vitamins A, D, E and K, which do accumulate.
It acts as a cofactor in several metabolic reactions. It is found in egg yolk, liver, pulses, nuts and certain vegetables. In countries with a varied diet, insufficient intake is rare.
The only sentence allowed in Europe
European regulation 432/2012 sets the list of authorised health claims. For biotin and hair, there is exactly one:
« Biotin contributes to the maintenance of normal hair. »
Every word has been weighed.
« Contributes », not « enables » or « ensures »: it plays a part, among other factors.
« To the maintenance », not « to the improvement ». Maintaining a state is not transforming it.
« Of normal hair »: the ordinary physiological state, not an improved one.
Anything beyond that sentence is not permitted. Not on a bottle, not on a website, not in an Instagram post, and not on a photo of packaging — a claim in an image carries exactly the same legal weight as a claim in text.
We make two in total: this one, and « vitamin C contributes to the reduction of tiredness ». That is all.
Why 10,000 µg when the reference is 50 µg?
That is the question that deserves an honest answer.
The European reference intake for biotin is 50 µg per day. COMAI BIOTINE provides 10,000 µg per 15 mL dose, 200 times more.
Not because 200 times more would produce 200 times the effect. It is a formulation choice, common for this kind of product, made possible by the fact that biotin is water-soluble and well tolerated: the excess is eliminated.
What that figure does not say: it guarantees no additional result. A high dose is a high dose. We state it because it is a fact of composition, not because it promises anything.
The point almost nobody mentions
A high dose of biotin can distort certain blood tests.
This is not a safety question for you, but a question of result reliability: biotin interferes with the assay technique used by many laboratories. Affected tests include thyroid assays (TSH, T3, T4), troponin — a marker used in cardiac emergencies — and other hormone assays. The result can come out artificially high or low.
What to do is simple:
- Always state that you are taking biotin, both to the doctor prescribing the test and to the laboratory taking the sample.
- Stop taking it at least 3 days before a blood test, unless your doctor advises otherwise.
No brand has a commercial interest in writing this. That is precisely why we write it.
Liquid or tablet?
A liquid form is already in solution: it does not go through the disintegration step a tablet requires. The graduated cap allows the dose to be adjusted.
These are two practical advantages, not a promise of greater efficacy. We have no comparative study to show you, so we claim nothing more.
What we will not tell you
We will not tell you how long it will take before you see something, nor what you will see.
Hair follows a biological cycle counted in months. A food supplement is not a medicine: it complements a diet, it treats nothing. And it replaces neither a varied diet nor a healthy lifestyle.
What we can say is verifiable line by line: what is in the bottle, in what quantity, where it is made, under what notification number. Everything is published on the Our formulas page and on About us.
COMAI BIOTINE is a food supplement for adults only, 18 and over. Do not exceed 15 mL per day. A food supplement does not replace a varied, balanced diet and a healthy lifestyle. Keep out of reach of young children.
