Benzisothiazolinone (and) Methylisothiazolinone (and) Ethylhexylglycerin

Geogard ECT is a broad-spectrum preservative blend combining Benzisothiazolinone (BIT) and Methylisothiazolinone (MIT), two isothiazolinone-class biocides, with Ethylhexylglycerin, a multifunctional glyceryl ether that acts as a skin-conditioning booster and enhances antimicrobial efficacy. The isothiazolinone components work by disrupting microbial cell membranes and inhibiting enzyme function, while Ethylhexylglycerin reduces the surface tension of microbial cell membranes, allowing the active biocides to perform at lower concentrations. Formulators choose this system for its exceptionally wide pH tolerance (2–12), broad-spectrum efficacy against bacteria, yeast, and mold, and its compatibility with a diverse range of cosmetic formulation types including rinse-off and leave-on products, though its use has come under increasing regulatory scrutiny in Europe due to sensitization concerns associated with MIT.