Kathon CG is a 3:1 mixture of Methylchloroisothiazolinone (5-chloro-2-methyl-4-isothiazolin-3-one; MCI) and Methylisothiazolinone (2-methyl-4-isothiazolin-3-one; MI). This mixture of two isothiazoles is often used in cosmetics and industry as a preservative.
Kathon CG is used at very low concentrations, in the range of 0.0003-0.0015%, and even at these levels, it reliably prevents the growth of bacteria, mold, and fungi. It acts as a bactericidal and preservative within the isothiazolinone class and is often used in cosmetics, shampoos, soaps, body care products, coolants, etc.
Kathon CG is used in personal care products like shampoos, soaps, hair conditioners, hair and body gels, skin creams and lotions, and masks. It is also used in many household products, such as detergents, bubble baths, adhesives, glues, wet wipes, fabric softeners, cleaning products, and even toilet paper.
It is a known sensitizer. Products containing Kathon CG can cause eczema-like allergic reactions in the affected skin areas. More research may show that the substance appears in more products and in other areas of use. The first cases of contact dermatitis to these substances appeared in the mid-seventies, and later, there was a noticeable increase in them.Leave-on products (moisturizers, etc.) containing Kathon CG produce more reactions than rinse-off products used for washing (soap, shampoo, etc.). This preservative is not approved for use in pharmaceuticals.
