Cetyl ethylhexanoate is a synthetic ester of cetyl alcohol and 2-ethylhexanoic acid. Cetyl alcohol is a fatty alcohol produced through the reduction of palmitic acid, which is obtained from palm oil. Cetyl alcohol is commonly used in cosmetic formulation as an emollient, emulsifier, thickener, and surfactant. 2-ethylhexanoic acid is a carboxylic acid that is widely used to prepare lipophilic metal derivatives that are soluble in nonpolar organic solvents.
Cetyl ethylhexanoate is an odorless, colorless liquid that is insoluble in water, but freely miscible with vegetable, mineral, and synthetic oils and fats. It is often used as a base oil in the production of a wide variety of cosmetics and personal care products. For example, it can be found in products such as makeup remover, lipstick, foundation, facial moisturizer, anti-aging treatment, lip/eye liner, hair conditioner, and eye shadow. This ingredient should not be confused with cetearyl ethylhexanoate, which has a similar chemical composition but slightly different properties and safety.
In cosmetics and personal care products, cetyl ethylhexanoate functions as a skin and hair emollient, as well as a texture enhancer.
As an emollient, cetyl ethylhexanoate works to soften, soothe, and lubricate the skin. It also acts as an occlusive agent by forming a protective, water-repelling film on the surface of skin. The film 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). Using a product that contains cetyl ethylhexanoate can help to improve symptoms such as skin dryness and flaking.
Cetyl ethylhexanoate is often used in hair care products due to its emollient properties. By coating the hair with a protective film, this ingredient provides increased slip between adjacent hair strands, which makes detangling easier. Cetyl ethylhexanoate further reduces tangling by smoothing and flattening the cuticle surface, which can also add shine and gloss to the hair. It leaves the hair feeling soft and silky without weighing it down or making it feel greasy.
As a texture enhancer, cetyl ethylhexanoate improves the spreadability of a product and provides a velvety and silky feel to the skin that is non-greasy. Cetyl ethylhexanoate also imparts water-repelling characteristics to cosmetics and personal care products. It has exceptional clarity and low odor, making it ideal for fragranced products. Cetyl ethylhexanoate is also recommended for dry oil sprays, makeup removers, matte finish makeup, and for inclusion in moisturizers for oily skin.
Cetyl ethylhexanoate can improve the fluidity of emulsions, which modifies the product’s rheology. Rheology can be defined as “the science or study of how things flow”, and it is a requirement of personal care products that they flow in the right way. For example, a skin cream should have a rich, thick appearance in the jar, but should be capable of being easily picked up and spread into the skin. Thus, cetyl ethylhexanoate can be added to a formulation to adjust the product flow.
The Cosmetic Ingredient Review (CIR) Expert Panel (Panel) assessed the safety of 16 alkyl ethylhexanoates, including cetyl ethylhexanoate, as used in cosmetics. The highest concentration of use reported for any of the alkyl ethylhexanoates is 77.3% cetyl ethylhexanoate in rinse-off formulations used near the eye, and the highest leave-on use reported is 52% cetyl ethylhexanoate in lipstick formulations.
The Panel reviewed available animal and clinical data related to these ingredients. Due to the similarities in structure, properties, functions, and uses of ingredients from previous CIR assessments on constituent alcohols, the Panel was able to extrapolate the available toxicological data to assess the safety of the entire group. The Panel concluded that these ingredients are safe in cosmetic formulations in the present practices of use and concentrations when formulated to be non-irritating.
References: Wikipedia, “Cetyl alcohol”, Wikipedia, “2-ethylhexanoic acid”, Truth In Aging, “Cetyl ethylhexanoate”, Naturally Curly, “Hair Moisturizer vs. Emollients”, 2013, Cosmetic Science Technology, “Rheology Modifiers for Skin Care Applications”, 2007, Cosmetic Ingredient Review, “Amended Safety Assessment of Alkyl Ethylhexanoates as Used in Cosmetics”, 2013.