Isononyl Isononanoate Good Emollient No known benefits Isononyl Isononanoate at a glance Synthetic ester that functions as an emollient skin-softening agent Derived from the esters of nonanoic acid, which occurs naturally Typically used in concentrations between 2–10% Ruled safe as used in cosmetics Isononyl Isononanoate description Isononyl isononanoate is a synthetic ester that functions as an emollient skin-softening agent. It is derived from the esters of nonanoic acid, a 9-carbon fatty acid which occurs naturally in cocoa oil and lavender oil (along with many other plant oils). It is typically used in cosmetics in concentrations between 2% - 10%. The Cosmetic Ingredient Review Expert Panel has determined that isononyl isononanoate is safe in its current use and concentration in cosmetic products. It found that in concentrations of less than 12%, nonanoic acid is not a skin irritant.