Ingredient
Diazolidinyl Urea
A formaldehyde-releasing preservative, often paired with a paraben or with phenoxyethanol.
- 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 we don't know
- Where it comes from — plant, mineral, synthetic — isn't recorded.
- No published rule in our reference names it. That is about the rules, not safety.
- 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.