What it is
Ethyl isostearate is a fluid ester that gives a light, low-tack emollient feel and improves the spreadability of a formula. Because of its low viscosity and good solvency, it is useful in fluid sunscreens and lotions where a fast-absorbing, non-heavy finish is desired. The branched isostearic chain helps keep it liquid and resistant to oxidation.
Safety & warnings
Considered a mild, well-tolerated emollient with a low irritation profile. The branched-chain structure tends to be associated with a low likelihood of pore-clogging, though individual responses vary for acne-prone skin. It is not a known fragrance allergen.
Origin & sourcing
Synthetic; produced by esterifying isostearic acid with ethanol.
Questions everyone asks
What does ethyl isostearate do?
It is a light emollient and solvent that helps a product spread easily and absorb with a non-greasy finish.
Is it likely to clog pores?
Branched esters like this are generally considered low risk for clogging pores, but acne-prone users may still want to monitor their own skin.