Cited skincare — every flag names its source, no upsell.What it does
It keeps products from spoiling and is often paired with parabens so together they cover bacteria and fungi. It releases less formaldehyde than DMDM hydantoin or quaternium-15, but patch tests still find reactions, and people allergic to formaldehyde usually react to this whole group. If preservatives or fragrance bother your skin, skip it.
The EU’s ingredient database lists it as a preservative (holds back germs in the product).European Commission, CosIng (© European Union, CC BY 4.0) · uses put in plain words by Drop ↗
The evidence, graded
moderateFragrance, essential oils, denatured alcohol and certain preservatives (methylisothiazolinone, the formaldehyde-releasers) are the usual suspects on sensitive skin. In the patch-test data read here — patients whose dermatitis was linked to a cleanser — the preservative quaternium-15 topped the list at 11.2% and fragrance mix I came fifth at 7.7%. Test a new product on a small patch of skin before you use it on your face.Warshaw 2018 · Dermatitis ↗ expert consensusSCCS/1632/21 (7 May 2021) advised on the threshold for the warning ‘contains formaldehyde’ for formaldehyde-releasing preservatives. It considered that the 0.05% threshold does not sufficiently protect consumers sensitized to formaldehyde. Reducing it by a factor of 50, to 0.001% (10 ppm) of total free formaldehyde, will protect the vast majority of them. The advice covered allergy to the formaldehyde released, not to the releasers themselves.SCCS 2021 · European Commission SCCS (final version, 7 May 2021) ↗ Graded per the methodology: strong · moderate · emerging · expert consensus. A weak source on a strong claim gets the weaker label.
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.