Is imidazolidinyl urea safe to use?

Imidazolidinyl urea is a formaldehyde-releasing preservative used to prevent microbial growth. It is one of the more frequently reported contact-allergy triggers among preservatives. People with eczema-prone skin, a known formaldehyde allergy, or previous sensitivity reactions should patch test or avoid products containing this ingredient.

Why is a formaldehyde-releasing ingredient allowed in cosmetics?

The EU permits imidazolidinyl urea up to a set maximum concentration with restrictions on free formaldehyde release above 0.05%, which requires a label warning. Like other preservatives, the ingredient must balance microbial safety of the product against individual sensitivity risk. For people without formaldehyde sensitivity, the published evidence supports that it is acceptable as used.

preservative

Imidazolidinyl Urea

Watch if sensitive·Strong evidence

A formaldehyde-releasing preservative used to extend shelf life. It is one of the more frequently reported contact-allergy triggers among preservatives, so people with sensitive or eczema-prone skin, or a known formaldehyde allergy, may want to patch test or avoid it.

Worth knowing

Known contact sensitizer for some
Can irritate, especially left on
Restricted in the EU

Permitted in the EU up to a set maximum concentration, with a formaldehyde warning label required above 0.05% free formaldehyde.

Gentler alternatives

Questions

Is imidazolidinyl urea safe to use?: Imidazolidinyl urea is a formaldehyde-releasing preservative used to prevent microbial growth. It is one of the more frequently reported contact-allergy triggers among preservatives. People with eczema-prone skin, a known formaldehyde allergy, or previous sensitivity reactions should patch test or avoid products containing this ingredient.
Why is a formaldehyde-releasing ingredient allowed in cosmetics?: The EU permits imidazolidinyl urea up to a set maximum concentration with restrictions on free formaldehyde release above 0.05%, which requires a label warning. Like other preservatives, the ingredient must balance microbial safety of the product against individual sensitivity risk. For people without formaldehyde sensitivity, the published evidence supports that it is acceptable as used.

Products with Imidazolidinyl Urea

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References

Cosmetic information for general education, not medical advice. A verdict is a reading of the published evidence, never a guarantee for your skin: any ingredient can irritate someone, so patch test new products and see a professional if you react. Concern is graded on cited evidence, never on hazard-score lists. See how we score.