Steareth-21 ek polyethylene glycol ether hai jo stearyl alcohol se bana hai. Isko skincare mein nonionic emulsifier aur surfactant ke taur pe use karte hain. Ye oil-in-water emulsions ko stable rakhta hai aur product ki texture ko better banata hai. Ye ek base ingredient hai jo formula ko smooth aur spreadable banane mein madad karta hai, na ki koi active ingredient.