What it is
Isostearyl linoleate is a liquid ester formed from branched isostearyl alcohol and linoleic acid, a polyunsaturated fatty acid. It is valued as a light, cushioning emollient that spreads easily and leaves a smooth, non-tacky finish, and it can also help dissolve and disperse other oil-soluble ingredients such as UV filters. In sunscreens it contributes to a pleasant skin feel and even film formation.
Safety & warnings
Isostearyl linoleate is generally well tolerated as an emollient. Some sources rate it as moderately comedogenic, so it may be worth noting for those prone to clogged pores or acne, although real-world comedogenicity depends heavily on the overall formula and use level. It is not a fragrance allergen.
Origin & sourcing
Synthetic ester, though it is built from fatty-acid building blocks that can be sourced from vegetable oils. It is made by reacting isostearyl alcohol with linoleic acid.
Questions everyone asks
Can isostearyl linoleate clog pores?
It has been rated as moderately comedogenic in some references, so people prone to congestion or breakouts may want to be aware of it, though formula context matters a great deal.
Why is it added to sunscreens?
It works as an emollient and solvent, giving a smooth, easy-spreading feel and helping disperse oil-soluble ingredients like UV filters.