Isothiazolinone preservatives

Never allowedReviewed September 18, 2026

Methylisothiazolinone · MIT · Methylchloroisothiazolinone · CMIT · Benzisothiazolinone · BIT

Extremely effective broad-spectrum preservatives, used at very low levels.

What it does: Preservation
Our take: Among the most potent contact allergens in personal care. The American Contact Dermatitis Society named MIT its Allergen of the Year in 2013 after a wave of sensitization cases, and the EU has since banned it outright from leave-on products.

What we read

EU Reg. 1223/2009; ACDS · reviewed Sep 2026

Every other ingredient, with the same treatment.

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never allowed28

ParabensPhthalatesFormaldehyde and formaldehyde-releasing preservativesPEG compoundsPolysorbatesEthoxylated ingredientsDEA, TEA and MEA compoundsBHA and BHTPetrolatum, mineral oil and paraffinIsothiazolinone preservativesRetinol and retinyl estersHydroquinoneChemical UV filtersTalcCoal tar and synthetic dyesPFAS and fluorinated compoundsTriclosan and triclocarbanAntibacterials and antimicrobials we excludeSynthetic fragranceSynthetic musksSodium lauryl and laureth sulfateEDTA and synthetic chelatorsIndustrial solventsHeavy metalsPlastic microbeads and film-formersAerosol propellantsOther synthetic preservatives we excludeCyclic silicones

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