Quaternium-18 hectorite (inci)

Quaternium (see also Polyquaternium) refers to complex quaternary ammonium compounds. Quaternary ammonium compounds, also called quats, have quaternary nitrogen atoms, i.e. all four hydrogen atoms of the ammonium ion (nitrogen atom) are replaced by organic residues. The compounds are therefore cationic, i.e. they have a positive charge. "tallow" denotes beef tallow, "hectorite", clay, a mixture of various clay minerals which is characterised by strong water absorption and swelling capacity.

The compound is used in cosmetic formulations. It acts as a viscosity regulator (increases or decreases the viscosity (toughness) of cosmetic products).