Sodium Methyl Stearoyl Taurate

Sodium methyl stearoyl taurate (SMT) is a synthetic anionic surfactant derived from stearic acid and the amino acid taurine. It functions as a cleansing agent and foaming ingredient commonly used in rinse-off products and emulsified formulations.In skincare, this ingredient serves a dual purpose: it removes oils and impurities from the skin surface, and it helps stabilise emulsions by reducing the interfacial tension between water and oil phases. This makes it particularly useful in formulae designed to remain stable over time without separation.

As an anionic surfactant, sodium methyl stearoyl taurate works by reducing the surface tension of water, allowing it to penetrate and lift away oils and dirt from the skin. One end of the molecule is attracted to oil, the other to water, so it essentially bridges these two substances and allows them to be rinsed away together.In formulated products, SMT stabilises oil-in-water emulsions by forming a protective layer around oil droplets, preventing them from coalescing and causing the formula to separate or break down over time.

This ingredient is most commonly encountered in rinse-off cleansers and daily-use emulsified moisturisers. As it is incorporated by formulators rather than used as a standalone product, consumers need not adjust usage based on SMT concentration alone. Follow the application instructions provided for the specific product.

Sodium methyl stearoyl taurate is generally well-tolerated and considered safe for skincare use at typical concentrations. It is mild enough for daily use, though those with very sensitive skin or specific surfactant sensitivities should patch test first.