What Is It?

The Ceteth ingredients (Ceteth-1, -2, -3, -4, -5, -6, -10, -12, -14, -15, -16, -20, -24, -25, -30 and -45) range from liquids to waxy solids. In cosmetics and personal care products, Ceteth ingredients are used in the formulation of hair dyes and colors, hair conditioners, permanent waves and other hair care products, as well as makeup foundations, cleansing products and other skin care products.

Why Is It Used?

The Ceteth ingredients help other ingredients to dissolve in a solvent in which they would not normally dissolve. Ceteths also help to form emulsions by reducing the surface tension of the substances to be emulsified and they clean the skin and hair by helping water to mix with oil and dirt so that they these substances can be rinsed away.

Scientific Facts

The Ceteths are prepared by reacting ethylene oxide with cetyl alcohol where the numerical value in the name corresponds to the average number of moles of ethylene oxide. For example, Ceteth-2 is prepared by reacting an average of 2 moles of ethylene oxide with cetyl alcohol.

Safety Information

The safety of Ceteth-1 to -45 has been assessed by the Cosmetic Ingredient Review (CIR) Expert Panel. The CIR Expert Panel evaluated the scientific data and concluded that Ceteth-1, -2, -3, -4, -5, -6, -10, -12, -14, -15, -16, -20, -24, -25, -30 and -45 were safe in the present practices of use.

CIR Safety Review: The CIR Expert Panel noted that not all of the polymer chain lengths covered in this assessment were reported to be used. All ingredients in the Ceteth family exhibit surfactant properties so the information from different studies were considered in support of the entire class. In separate studies, 2.5% Ceteth-2 was irritating to abraded skin, but 3.0% was not irritating to intact skin.

Dose-dependent irritation was noted for Ceteth-2 and Ceteth-10 at concentrations ranging from 5% to 100%. Ceteth-20 was found to enhance transposition of a marker from phage l to bacterial DNA. Toxicity data, including reproductive and developmental toxicity, carcinogenesis data, and clinical testing data, supporting the safety of Polyethylene Glycol (PEG) and Cetyl Alcohol, were considered. Based on a study reporting nephrotoxicity in burn patients exposed to PEGs, the CIREP recommended that PEGs not be used on damaged skin.

There was no kidney toxicity observed in patients with intact skin. Although metabolites of ethylene glycol monoalkyl ethers are reproductive and developmental toxins, the CIREP concluded that it is unlikely that the relevant metabolites would be found in or produced from the use of Ceteths in cosmetic formulations. Cetyl alcohol exposures at a concentration of 9.6 mg/L did not result in inhalation irritation although longer exposures at higher concentrations produced mucosal irritation. Based on this data and with particle size and cosmetic use concentrations, Ceteths were considered to be safe for aerosolized use. Small amounts of 1,4-dioxane, a by-product of ethoxylation, may be found in the Ceteth ingredients.

The potential presence of this material is well known and can be controlled through purification steps to remove it from the ingredients before blending into cosmetic formulations.

Link to more information about what the Food and Drug Administration (FDA) is doing to assure that cosmetics do not contain unsafe levels of 1,4-dioxane.

Ceteths-1 to -45 may be used in cosmetics and personal care products marketed in Europe according to the general provisions of the Cosmetics Regulation of the European Union. Ingredients of animal origin must comply with European Union animal by-products regulations.

EU Cosmetic Regulation

More Scientific Information

The Ceteth family of ingredients are the polyethylene glycol (PEG) ethers of cetyl alcohol. In cosmetics and personal care products, the Ceteths function as surfactants (emulsifying, cleansing, and solubilizing agents).