Keratin sits in our formulas for one job: conditioning hair and scalp. We file it under Hair & Scalp in this glossary because that is the effect its evidence actually supports, not because it is the most flattering label available.

Strength in the fibre

The mechanism is the one stated in the summary above, and we have deliberately not extended it. Where a supplier or a competitor would reach for a bigger promise, the sentence we publish stops where the research stops.

Strength in the evidence

Our source is a peer reviewed observational or laboratory study, recorded as Fan 2025 PMID 40076404. You can read it yourself at PubMed 40076404. We grade that as solid support for what the ingredient does.

Strength and its limits

The research behind Keratin studies the ingredient, not the finished Opuliss product it sits in. It supports what Keratin does. It is not a trial of our formula, and we will not present it as one.

Cosmetic claims describe how skin looks and feels. Nothing here is a medical claim, and nothing here treats a condition.