Ethanolamines are also called olamines or colamines. You may often find them listed on your label as MEA (monoethanolamine), DEA (diethanolamine), and TEA (triethanolamine). Sometimes their amide, phosphate, or sulfate versions are listed, e.g. palmitamide DEA, DEA-cetyl phosphate, TEA-lauryl sulfate, cocamide MEA, cocamide DEA, oleamide DEA, stearamide MEA, myristamide DEA, lauramide DEA, linoleamide MEA, ricinoleamide DEA, and DEA oleth-3 phosphate.

Ethanolamines are viscous, hygroscopic liquids and are a constituent of urine. They’re synthesized by ethoxylating ammonia, i.e. subjecting ammonia to ethylene oxide, a dangerous chemical discussed under polysorbates, steareths, SLS, and SLES. No wonder they smell like ammonia. As the name suggests, ethanolamines are both primary amine and primary alcohol. For this reason, they can undergo reactions common to both groups.

They’re included in personal care products for several reasons. Their mildly alkaline properties make them good pH regulators. They’re excellent emulsifiers for oil-in-water emulsions. They’ve got antimicrobial properties that make them useful as preservatives. DEA is used to prepare fatty acid amides, a viscosity-increasing agent found in many personal care products, including shaving creams, hand and body lotions, and gel-type industrial hand-cleaners. TEA is combined with lauryl sulfates to produce foaming surfactants (to lower the surface tension of other liquids), which are included in shampoos, facial cleansers, body washes, sunscreens, mild bar soaps and other personal care product formulations.

Ethanolamines have several other applications: absorbing acidic gases such as carbon dioxide, sulfur dioxide, and hydrogen sulfide in natural gas purification; inhibiting corrosion; preventing metal rusting; manufacturing herbicides and insecticides; softening and finishing leathers; accelerating the production of antibiotics and polishes; adding to pharmaceutical formulations, e.g. ear drops for treating wax; improving the flow and setting of cement; and as a complexing agent in electroless plating.

Exposure to ethanolamines is via skin contact, ingestion, and inhalation. Very low exposure permeates the skin and produces significant irritation, redness and rashes within one-and-a-half hours, followed by necrosis (death of cells), scabs, and scar formation. Repeated exposure can cause restlessness, bronchitis, and damage to central nervous system, spleen, gastro-intestinal tract, lung, kidney, blood, and liver.

Ethanolamines can suppress sperm formation and increase fetal toxicity and malformations as well tumor formation. They induce chromosome damage in blood cells which can lead to cancer. They can react with other chemicals in your product and undergo nitrosation, breaking down into nitrogen and forming nitrosamines, which is classified as cancer-causing (carcinogenic) by the International Agency for Research on Cancer and the US Environmental Protection Agency (see aminomethyl propanol and sodium lauryl sulfate).

Because of the severity of its effects, it is advisable to use deodorant and products containing ethanolamines very briefly and intermittently, and immediately rinsing them off. This has been the recommendation of the Cosmetic Ingredient Review Expert Panel, an independent non-profit organization that works collaboratively with the Consumer Federation of America and the US Food and Drug Administration to assess the safety of cosmetic ingredients.