Which skincare preservatives release formaldehyde?

Quaternium-15, DMDM hydantoin, imidazolidinyl and diazolidinyl urea all release formaldehyde.

Preservatives that work by releasing small amounts of formaldehyde. Someone sensitised to formaldehyde generally reacts to the releasers as a group rather than to one of them.

Information, not medical advice. A suspected contact allergy should be confirmed by a dermatologist through patch testing.