Plant-derived cleaning products made for everyday homes • Used by humans since 2012.

Diethanolamine

Diethanolamine

What It Is

Diethanolamine (DEA) is an organic compound with the chemical formula HN(CH2CH2OH)2 (CAS 111-42-2). It is a clear, viscous, hygroscopic liquid produced by reacting ethylene oxide with ammonia. DEA is classified as a secondary amine and a diol (it has two hydroxyl groups). In cleaning and personal care products, DEA and its fatty acid derivatives (such as cocamide DEA and lauramide DEA) function as pH adjusters, emulsifiers, and foam boosters.

Common Uses

DEA and DEA-based compounds (cocamide DEA, lauramide DEA, linoleamide DEA) are used in shampoos, liquid soaps, dish soaps, all-purpose cleaners, and cosmetics as foam stabilizers, viscosity builders, and emulsifiers. DEA itself also has industrial applications as a chemical intermediate in the production of herbicides, rubber chemicals, and metalworking fluids. Its use in consumer products has declined significantly over the past two decades as manufacturers have reformulated to avoid DEA-related concerns.

How It Works

In cleaning and personal care formulations, DEA and its fatty acid derivatives serve multiple functions. The amine group can neutralize acids (adjusting pH), while the hydroxyl groups interact with water. Fatty acid DEA compounds (like cocamide DEA) have an amphiphilic structure that stabilizes foam and increases the viscosity of surfactant solutions. Cocamide DEA, for example, acts as a foam booster by reducing the surface tension of the air-liquid interface within foam bubbles, making them more stable and longer-lasting.

Safety and Regulation

The primary safety concern with DEA is nitrosamine formation. DEA can react with nitrosating agents (present in some other cosmetic ingredients or as environmental contaminants) to form N-nitrosodiethanolamine (NDEA), a probable human carcinogen (IARC Group 2B). The FDA issued an advisory in the 1980s warning against the use of DEA in cosmetics that also contain nitrosating agents, and recommended that manufacturers test for NDEA contamination (FDA, 1979 advisory; Industry Alert, 1996).

The CIR Expert Panel concluded in 2012 that DEA is safe for use in cosmetics in the present practices of use and concentration when formulated to avoid the formation of nitrosamines (CIR, 2012). The EU Cosmetics Regulation (EC No 1223/2009) restricts secondary amines including DEA in cosmetic formulations and sets maximum limits for nitrosamine contamination.

The National Toxicology Program (NTP) found that DEA itself (separate from nitrosamines) caused liver tumors and kidney tumors in mice when applied dermally at high doses in a two-year study (NTP, 1999). These findings were at concentrations and durations substantially higher than consumer product exposure, but they contributed to the trend away from DEA in consumer formulations.

Why Natural Flower Power Does Not Use It

Natural Flower Power does not use diethanolamine or any DEA-based compounds (cocamide DEA, lauramide DEA, etc.) in any product.

The nitrosamine contamination risk is the primary reason. While the risk is manageable through formulation controls (avoiding nitrosating agents, testing for NDEA), we chose to eliminate the concern entirely by using alternative ingredients that do not carry this contamination vector. Our formulations use cocamide DIPA as a foam booster and viscosity builder instead of cocamide DEA -- cocamide DIPA is not a secondary amine and does not form nitrosamines under normal conditions. For pH adjustment, we use citric acid rather than amine-based pH adjusters.

Related Ingredients

Triethanolamine (TEA) is a related ethanolamine with three hydroxyl groups instead of two, sharing similar nitrosamine concerns. Cocamide DIPA is the foam booster and viscosity builder Natural Flower Power uses instead of cocamide DEA. Citric acid is the pH adjuster NFP uses in place of amine-based pH adjustment systems. Monoethanolamine (MEA) is another ethanolamine compound with a single hydroxyl group, also carrying nitrosamine formation potential.

Sources

  • Cosmetic Ingredient Review (CIR). "Amended Safety Assessment of Diethanolamine and Its Salts as Used in Cosmetics." International Journal of Toxicology, vol. 31, Suppl. 2, 2012, pp. 28S-44S.
  • National Toxicology Program (NTP). "Toxicology and Carcinogenesis Studies of Diethanolamine." NTP TR 478, 1999.
  • U.S. Food and Drug Administration. "Cosmetics: Nitrosamines Impurities in Cosmetics." FDA Industry Alert, 1996.

Disclaimer

The information provided in this ingredient guide is for general educational purposes only. It is intended to explain how individual ingredients are commonly used in formulated products and does not constitute medical, safety, regulatory, or professional advice.

Ingredient function, safety considerations, and regulatory status can vary depending on formulation, concentration, product type, and intended use. Individual sensitivities may also vary. Always refer to product labels, safety data sheets, and applicable regulations for complete and current information.

Regulatory frameworks and requirements may change over time. References to regulatory context reflect general conditions as of the date noted and are not a claim of approval, certification, or compliance for any specific product.

This content does not replace professional evaluation, testing, or compliance review and should not be used as the sole basis for product selection or use decisions.