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Ingredient

DMDM Hydantoin

A preservative that works by slowly releasing small amounts of formaldehyde. EU rules require products above a threshold to carry a specific label warning.

  • Preservative

What it is there to do

  • Preservative

    Keeps the product free of microbial growth in use.

Where this comes up

The notes BeautySignal puts beside this ingredient when it is on a label.

  • Contains a formaldehyde-releasing preservative

    This product contains a preservative that works by slowly releasing formaldehyde. EU rules require products above a threshold to carry a specific label warning.

    Why we mention it

    This group is genuinely subject to a labelling obligation, so it is marked regulatory. The ingredient is not formaldehyde itself, and the flag says so.

What the rules say

Each line names the rule it comes from. A limit is not a warning.

  • EU · Restricted

    Regulation (EC) No 1223/2009, Annex V

    What it sets out

    Products releasing formaldehyde above the threshold must be labelled 'releases formaldehyde'.

What we don't know

  • Where it comes from — plant, mineral, synthetic — isn't recorded.
  • How much of it is used in any particular product. We hold no concentrations at all.

This is information about an ingredient, not medical advice, and not a judgement about any product that contains it. Back to the reference.