Potassium Stearate Bon Émulsifiant No known benefits Potassium Stearate at a glance Potassium salt of stearic acid Primarily used as an emulsifier to keep water and oil-based ingredients from separating Also used as a cleanser Ruled safe as used in cosmetics Potassium Stearate description Potassium stearate is the potassium salt of the fatty acid stearic acid. According to one of its manufacturers, it is primarily used as an emulsifier in cosmetics, meaning it keeps water and oil-based ingredients from separating. It also serves the same function in food products. It also works as a cleansing ingredient and is often found in traditional bar soaps for both its cleansing and emulsifying abilities. A fine, white powder in pure form, potassium stearate has been ruled safe as used in cosmetics (where it is used in amounts up to 7.5% in leave-on products) by the independent Cosmetic Ingredient Review panel. Related ingredients: Potassium Stearic Acid