Ethoxydiglycol is a cosmetic grade solvent that is used in various skin and hair care products to dissolve ingredients, increase the efficacy of active ingredients, and decrease the viscosity of formulations.
Ethoxydiglycol, also known as diethylene glycol monoethyl ether (DEGEE), is produced by the ethoxylation of ethanol. Ethoxylation is a chemical reaction in which ethylene oxide is added to a substrate. In this case, the substrate is ethanol, otherwise known as alcohol.
Ethoxydiglycol can be classified as a glycol. The molecular structure of a glycol contains two hydroxyl (−OH) groups attached to different carbon atoms. In addition to ethoxydiglycol, there are many different types of compounds that belong to this family, such as propylene glycol, butylene glycol, polyethylene glycol, and more. Ethoxydiglycol is a colorless liquid with a mild, pleasant odor.
In cosmetics and personal care products, ethoxydiglycol primarily functions as a solvent. The term ‘solvent’ derives from Latin, meaning to loosen. Solvents help to dissolve or suspend other ingredients in a formulation without chemically altering either the solvents or the other ingredients. Without solvents, many products would not perform as well.
Ethoxydiglycol is soluble in ethanol, propylene glycol, vegetable oils, water, and butylene glycol. It can be used in hydrophilic or lipophilic phases. Due to its solubilizing properties it has application in almost every type of cosmetic product, including antiperspirants, antimicrobial soaps, nail polish removers, fragrances, hair conditioners, hair dyes, and a variety of skin care products. It is typically used at concentrations between 1 and 10%.
Solvents can also increase the efficacy of active ingredients in a product formulation by enhancing their absorption through the skin. For example, ethoxydiglycol is often used to boost the efficacy of active ingredients like vitamin C, self-tanning active DHA, or benzoyl peroxide. In addition to skin care products, ethoxydiglycol can be used in hair care products where it gives a longer-lasting and more uniform coloring. According to a manufacturer, it might even prevent the formation of split ends.
Furthermore, solvents like ethoxydiglycol are used to thin out formulations and decrease viscosity. The term viscosity corresponds to the concept of “thickness”, for example, honey has a higher viscosity than water. Decreasing the viscosity of a formulation makes the product more spreadable when applied to the skin or hair.
Lastly, ethoxydiglycol functions as a humectant moisturizer. A humectant is a hygroscopic substance that has a molecular structure with several hydrophilic (water loving) groups. This structure allows humectants to attract and retain the moisture in the air nearby via absorption, drawing the water vapor into or beneath the surface. Humectants improve moisture retention and may also help other topical skin care ingredients to perform better.
Humectants like ethoxydiglycol not only help to prevent dry skin, but also work to delay signs of aging. As the skin loses moisture due to both internal and external factors, it begins to show signs of aging, such as lines, wrinkles, sagging, and flaking skin. Therefore, using skin care products that contain humectants will help to attract moisture to the skin, resulting in smoother, softer skin with decreased wrinkles and a more plump appearance.
According to the Skin Care and Cosmetic Ingredients Dictionary, ethoxydiglycol is non-irritating, non-penetrating, and non-comedogenic when applied to the skin. The safety of ethoxydiglycol has been assessed by the Cosmetic Ingredient Review (CIR) Expert Panel. The Panel found that acute, subchronic, and chronic oral toxicity studies indicated a low order of toxicity for this ingredient. Overall, the Panel concluded that ethoxydiglycol was safe for use in cosmetics and personal care products.
References: Wikipedia, “2-(2-Ethoxyethoxy)ethanol”, Chemicalsafetyfacts.org, Lotioncrafter, “Ethoxydiglycol”, INCI Decoder, “Ethoxydiglycol”, Cosmetics Info, “Ethoxydiglycol”.