Cited skincare — every flag names its source, no upsell.

Caprylhydroxamic Acid

Keeps germs out of a product and binds stray metals across a wide pH range. Common in "preservative-free" style products.

What it does

Caprylhydroxamic acid helps keep products free of microbial growth and binds metal ions, and it stays effective across a wider pH range than some preservatives. It is frequently paired with glycols in "preservative-free"-style systems. Its role is keeping the formula safe and stable, not acting on the skin.

The EU’s ingredient database lists it as a chelating agent (holds on to metals that could spoil the product).European Commission, CosIng (© European Union, CC BY 4.0) · uses put in plain words by Drop ↗

The evidence, graded

expert consensusUS safety reviewers (2025) say products use caprylhydroxamic acid to bind metals. Allergy cases rose in Finland after a moisturizer was changed to include it, and the reviewers linked them to use on damaged skin. In a patch test of 39 people with damaged skin who suspected it, some reacted to the ingredient itself; 33 comparison people, 20 with eczema, didn’t. The reviewers judged it safe as used, but cautioned against formulas that let more of it into skin.Fiume 2025 · International Journal of Toxicology ↗

Graded per the methodology: strong · moderate · emerging · expert consensus. A weak source on a strong claim gets the weaker label.

Also known as

CHA

Browse all 1238 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.

Want more like this?

Every evidence-based flag cites its source, Drop tells you when your routine is complete, and it helps you simplify — instead of selling you more. The app launches on iOS and Android in October 2026. Rate my routine works today at /rate — no sign-in.

See what Drop does How Drop works