Isostearyl neopentanoate is an ester of isostearyl alcohol and neopentanoic acid. Isostearyl alcohol is a mixture of branched chain 18 carbon aliphatic alcohols. Neopentanoic acid is a carboxylic acid. Isostearyl neopentanoate is used in the formulation of eye makeup, primarily eye shadows, as well as in blush and foundation, where it functions as a binder. A binder works to bind other ingredients together and prevent them from coming apart. For example, binders are often used in pressed powders to keep them together in the container.

Isostearyl neopentanoate can also be used in skin care products, such as cleansers and moisturizers, where it functions as an emollient. Isostearyl neopentanoate works to soften and smooth the skin by lubricating the skin’s surface. It forms a film that helps to prevent evaporation of the skin’s natural moisture. Over time, this increases skin hydration by causing buildup of water in the stratum corneum (the uppermost layer of skin). While all skin types can benefit from emollients like isostearyl neopentanoate, emollients are especially helpful for those who have dry, rough, and/or flaky skin. Emollients can alleviate these symptoms, leaving the skin looking and feeling soft and smooth.