Steareth-40

Steareth-40 is a non-ionic surfactant derived from stearyl alcohol (a fatty alcohol) combined with ethylene oxide. It belongs to a class of ingredients commonly used in skincare formulations to improve texture and stability.In cleansers and other products, it works to lift away oils and impurities from the skin surface whilst helping to blend oil and water-based ingredients together. It is gentler than many traditional surfactants, making it a popular choice in formulations designed for sensitive or compromised skin.

Steareth-40 has a molecular structure that allows it to interact with both water and oils. One end of the molecule is attracted to oil-based substances, whilst the other attracts water. This dual affinity enables it to encircle oil and dirt particles, suspending them so they can be rinsed away.As a non-ionic surfactant, it carries no electrical charge, which generally makes it less irritating to skin than ionic alternatives. It also functions as a solubiliser and emulsifier, helping skincare products maintain a uniform appearance and texture.

Steareth-40 is typically incorporated into cleansers, micellar waters, and makeup removers where it does the work during cleansing. Use as directed by the specific product instructions—usually this means applying to damp or dry skin, massaging gently, and rinsing thoroughly with water. No specific additional precautions are needed beyond standard cleansing practice.

Steareth-40 is generally well-tolerated and is approved for use in cosmetics in the UK and EU. As with any surfactant, it can potentially irritate eyes or very sensitive skin if used excessively or not rinsed thoroughly.