What it is
Methylheptyl isostearate is the ester of methylheptyl alcohol and isostearic acid, a branched fatty acid. Its branched structure makes it a light, non-greasy emollient that spreads easily and imparts a soft, cushiony feel. In mineral sunscreens it can also help wet and disperse UV-filter powders such as zinc oxide and titanium dioxide.
Safety & warnings
Branched-chain esters like this are generally well tolerated and tend to have a lower comedogenicity than many straight-chain fatty esters, though individual responses vary. It is not associated with fragrance allergens.
Origin & sourcing
Synthetic ester, made by combining a branched fatty alcohol with isostearic acid.
Questions everyone asks
What does methylheptyl isostearate do?
It is a lightweight ester emollient that softens skin, improves spreadability, and helps disperse mineral UV filters.
Is methylheptyl isostearate likely to clog pores?
Branched esters like this generally have a lower pore-clogging tendency than many straight-chain oils, but reactions can vary by person.