Isodecyl neopentanoate is a synthetic ingredient that is used in cosmetics and personal care products as an emollient and skin conditioning agent. It is primarily used in facial skin care products and sunscreens.
Isodecyl neopentanoate is the ester of branched chain decyl alcohols and neopentanoic acid. Decyl alcohol is a straight chain fatty alcohol with ten carbon atoms that can be derived from decanoic acid, a fatty acid naturally found in coconut oil and palm kernel oil. Neopentanoic acid is a carboxylic acid.
In cosmetics and personal care products, isodecyl neopentanoate functions as an emollient and skin conditioning agent. It is primarily used in facial skin care products and sunscreens.
As an emollient, isodecyl neopentanoate works to soften and soothe the skin (or hair) while also acting as an occlusive agent. Upon application, occlusive agents form a protective film on the surface of skin, which 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). These same properties also help to keep the hair soft, hydrated, and manageable.
While all skin types can benefit from emollients like isodecyl 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. In addition, emollients can benefit those that suffer from conditions such as eczema, psoriasis, or other inflammatory skin conditions.
One manufacturer of isodecyl neopentanoate states that it can be used as an alternative to cyclomethicone in any formulation. Cyclomethicone is a synthetic silicone oil that functions as an easily spreadable, silky moisturizer in skin care products. Isodecyl neopentanoate provides high spreadability, high slip, and a soft skin feel that is very similar to cyclomethicone. For this reason, isodecyl neopentanoate is often used in light creams and lotions.
Isodecyl neopentanoate is frequently used in sun care applications due to its emolliency and spreadability, as well as for its ability to function as a solvent for solid UV absorbers. UV absorbers are also known as chemical sunscreens, which work by absorbing UV light and then transforming that light energy into some other form of energy, such as heat. Common UV absorbers include oxybenzone, octinoxate, avobenzone, and homosalate. Isodecyl neopentanoate helps these ingredients to dissolve better in a formulation and also reduces the oily or heavy feeling they can cause after topical application.
The safety of isodecyl neopentanoate and the other alkyl ester ingredients has been assessed by the Cosmetic Ingredient Review (CIR) Expert Panel. After evaluating the scientific data, the CIR Expert Panel concluded that all alkyl ester ingredients are safe in the present practices of use and concentration when formulated to be non-irritating in cosmetics and personal care products.
The safety of isodecyl neopentanoate has also been assessed by EWG’s Skin Deep Cosmetic Database. It is rated as a 1 on a scale of 1 to 10, with 1 being the lowest risk to health and 10 being the highest. However, the Database does indicate that there is limited data available regarding isodecyl neopentanoate.
References: Lubrizol “Schercemol™ 105 ester”, Cosmetic Ingredient Review “Amended Safety Assessment of Alkyl Esters as Used in Cosmetics” 2013, EWG’s Skin Deep Cosmetic Database “Isodecyl Neopentanoate”