What it is
Steareth-10 is made by ethoxylating stearyl alcohol with an average of ten units of ethylene oxide, producing a nonionic surfactant with a higher hydrophilic balance than lower-numbered steareths. This water-friendly character makes it useful for stabilizing oil-in-water emulsions and helping disperse oils. In sunscreens it contributes to a stable, spreadable lotion or cream base.
Safety & warnings
Steareth-type ethoxylated emulsifiers are widely used and generally well tolerated on skin. Because they are made with ethylene oxide, suppliers control for residual 1,4-dioxane and ethylene oxide to keep them within accepted limits. They are not associated with significant comedogenicity at typical use levels.
Origin & sourcing
Synthetic; produced by reacting stearyl alcohol (a fatty alcohol, often plant- or petrochemical-derived) with ethylene oxide.
Questions everyone asks
What is the number in steareth-10?
It indicates the average number of ethylene oxide units (10) added to stearyl alcohol, which raises the ingredient's affinity for water.
Why is it in sunscreen?
It works as a nonionic emulsifier that helps blend oil and water phases into a stable, even cream or lotion.