Steareth-20

Steareth-20 is a non-ionic surfactant derived from stearyl alcohol, a fatty alcohol. It functions as both a cleansing agent and an emulsifier—helping oil and water-based ingredients mix together in formulations. You'll find it in cleansers, micellar waters, and some moisturisers where stability and gentle cleansing are priorities.Non-ionic surfactants like this one are generally considered milder than their ionic counterparts, which is why they appear frequently in skincare designed for sensitive or compromised skin barriers.

Steareth-20 works by reducing surface tension between oil and water molecules. One end of its molecular structure is water-loving (hydrophilic) whilst the other is oil-loving (lipophilic). This allows it to surround oil droplets and lift them away from the skin or suspend them in a cleanser, ready for rinsing.In formulations, it also acts as a bridge between incompatible ingredients, keeping moisturisers and serums homogeneous and preventing the product from separating over time.

Steareth-20 is typically used in leave-on products (moisturisers, serums) or rinse-off cleansers at low concentrations. If you use a cleanser containing this ingredient, apply to damp skin, massage gently, and rinse thoroughly with water. There is no need for special timing or frequency adjustments based on this ingredient alone.

Steareth-20 is generally well-tolerated and non-irritating at typical cosmetic concentrations. It is not classified as a skin sensitiser and poses minimal risk for most people, though patch testing is sensible if you have very reactive skin.