Ingredients

Bronopol — a preservative that can release formaldehyde and form nitrosamines.

Also written Bronopol

A formaldehyde-releasing preservative and a known cause of contact allergy.

A preservative that works by slowly releasing formaldehyde, a known sensitizer and carcinogen. Products containing releasers must carry a warning in the EU when formaldehyde levels are high.

Lyral. A strong fragrance allergen banned in EU cosmetics since 2021.

Also written HICC, Lyral

A formaldehyde-releasing preservative and a known cause of contact allergy.

A strong sensitizer, usually paired with MIT. Allowed only in rinse-off products in the EU.

Also written Kathon CG, MCI, Methylchloroisothiazolinone/Methylisothiazolinone

A preservative behind an epidemic of contact allergy in the 2010s. Banned in leave-on products in the EU; allowed only at low levels in rinse-off.

Also written MI, MIT

A formaldehyde-releasing preservative, banned in cosmetics in the EU.