methylchloroisothiazolinone

Methylchloroisothiazolinone is an isothiazolinone compound widely used as a preservative with antibacterial and antifungal properties. It is commonly found in water-based personal care products, cosmetics, lotions, makeup removers, glues, detergents, paints, fuels, and other industrial processes[2][4][5]. Its primary mechanism of action involves the oxidation of thiol-containing residues in microorganisms via its active sulfur moiety—effectively killing most aerobic and anaerobic bacteria as well as yeast and fungi[5]. Methylchloroisothiazolinone is also a known dermatological sensitizer and allergen; it can cause contact dermatitis and was named Contact Allergen of the Year by the American Contact Dermatitis Society in 2013[1][2][5]. In medicine it is approved for use within allergenic epicutaneous patch tests to aid diagnosis of allergic contact dermatitis in individuals aged six years or older[2].

Brand names

Kathon CG

Other names

chloromethylisothiazolinone5-chloro-2-methyl-4-isothiazolin-3-one