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Proline

ProlineHydrator

An amino acid used as a humectant and conditioning agent at the skin surface.

What it does

Proline is an amino acid. As a humectant it helps draw and hold water at the skin surface and acts as a conditioning ingredient that contributes to a smoother feel. It is a hydration ingredient rather than a skin active.

Browse all 668 ingredients — grouped by what they do, each with whatever evidence we can cite.

This page is public so a shared ingredient card always has its sources behind it — and so you can check them without an account.
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