What Is It?
Triethanolamine (TEA), Diethanolamine (DEA) and Ethanolamine are clear, colorless, thick liquids with ammonia-like odors. In cosmetics and personal care products, Triethanolamine may be used in some makeup products such as eyeliner, mascara, eye shadow, blush, make-up bases and foundations, as well as in fragrances, hair care products, hair dyes, wave sets, shaving products, sunscreens, and skin care and skin cleansing products. Ethanolamine may be used in some permanent waves and hair dyes and colors. Diethanolamine itself is rarely used in cosmetics, but derivatives of DEA may be used in shampoos and cleansing products.
Why is it used in cosmetics and personal care products?
TEA, DEA and Ethanolamine help to form emulsions by reducing the surface tension of the substances to be emulsified so that water-soluble and oil-soluble ingredients can be blended together. They are also used to control the pH of cosmetics and personal care products.
DEA itself is rarely used in products, but may be combined with other substances and converted into a new ingredient (i.e., DEA salt) that is no longer chemically identical with DEA. This “chemical reaction” leads to a new substance that is very stable and does not easily come apart. Cocamide DEA and lauramide DEA are examples of such ingredients. The DEA salts function as surfactants, emulsifying agents, viscosity increasing agents, hair or skin conditioning agents, foam boosters, or antistatic agents. It should be noted that DEA and derivatives of DEA are used in other products besides cosmetics and personal care products. For example, DEA and derivatives of DEA have been approved for several food-related applications, primarily food packaging. As with any chemical reaction, there may be unavoidable small amounts of the starting materials (in this case, DEA) carried into the final product. These low, residual levels do not impact the use or performance of the new ingredients and the levels are controlled to safe levels during manufacture. TEA is more commonly used in cosmetics and functions as a surfactant or pH adjuster.
Other TEA-containing ingredients function as surfactants and hair- or skin-conditioning agents. Ethanolamine functions as a pH adjuster. The majority of its salts function as surfactants; some of the ethanolamine salts function as pH adjusters, hair fixatives, or preservatives.
The U.S. Food and Drug Administration (FDA) includes Triethanolamine (TEA), Diethanolamine (DEA) and Ethanolamine on its list of allowed indirect food additives. These ingredients may be used in adhesives in contact with food and to assist in the washing or peeling of fruits and vegetables.
The safety of Triethanolamine, Diethanolamine and Ethanolamine has been assessed on several occasions by the U.S. nitrosamines.
European Union (EU)
Diethanolamine (DEA) is listed under secondary alkyl- and alkanolamine and their salts (see Annex II of the Cosmetics Directive), and is not permitted to be used in cosmetics and personal care products marketed in the European Union. Derivatives of DEA, however, are allowed for use if the content of DEA is less than or equal to 0.5%.
Triethanolamine (TEA) is listed as Trialkylamines, trialkanolamines and their salts, and Ethanolamine is listed as Monoalkylamines, monoalkanolamines and their salts, in Annex III, Part I of the Cosmetics Regulation of the European Union. Triethanolamine may be used in non-rinse-off and other cosmetics and personal care products at a maximum concentration of 2.5%. Ethanolamine can be used in cosmetics and personal care products if the secondary amine is less than or equal to 0.5%.
Neither Triethanolamine nor Ethanolamine can be used with nitrosating systems, they must have purity of 99% with a maximum secondary amine content of 0.5%, and a nitrosamine content of 50 micrograms/kg or less, and the products must be in nitrite-free containers.
The 2001 an opinion issued by the EU’s Scientific Committee for Cosmetic Products and Non-Food Products (SCCNFP; now known as the SCCS) stated that amines occur only in their salt form in all cosmetic products. The reason is that all amines are alkaline compounds which are always neutralized by an acid component to produce their salts, and there is concern about the potential for nitrosamine formation; in principle, secondary amines are potential precursors of nitrosamines.
NTP and IARC Reviews
The U.S. National Toxicology Program (NTP) develops, evaluates and disseminates scientific information about potentially toxic and hazardous chemicals. NTP conducts studies that are intended to identify a potential hazard but does not assess the risk posed by the material under specific conditions of use (e.g., in cosmetics). The NTP completed a study in 1998 that found an association between the topical application of DEA and certain DEA-related ingredients and cancer in laboratory animals. For the DEA-related ingredients, the NTP study suggests that the carcinogenic response is linked to possible residual levels of DEA. The NTP study did not establish a link between DEA and the risk of cancer in humans.
The International Agency for Research on Cancer (IARC), which is part of the World Health Organization, also assessed the possible carcinogenicity of DEA. The first IARC review took place in 2000 and considered all of the available evidence on DEA, concluding that there was “inadequate evidence in humans for the carcinogenicity of diethanolamine” and “limited evidence in experimental animals for the carcinogenicity of diethanolamine.” Therefore, IARC concluded that DEA was “not classifiable as to its carcinogenicity to humans.”
IARC issued an updated assessment in 2012, which concluded that there is “inadequate evidence” in humans for the carcinogenicity of diethanolamine and that there is “sufficient evidence” in experimental animals. Their overall conclusion was that Diethanolamine is “possibly carcinogenic” to humans (IACR carcinogenicity Group 2B).
As a result of these thorough assessments, the U.S. FDA has noted that “[t]he NTP study did not establish a link between DEA and the risk of cancer in humans.” and that “FDA believes that at the present time there is no reason for consumers to be alarmed based on the use of these substances in cosmetics.” The agency has advised that consumers wishing to avoid cosmetics containing DEA or DEA-related ingredients may determine whether these ingredients are in a cosmetic product by reviewing the ingredient statement on the outer container label.