Diethanolamine (DEA) and cocamide DEA: dangers, side effects and is it safe?

If you've read our article on triethanolamine, you already know half this story. Diethanolamine, or DEA, is its close chemical cousin: same family, same nitrosamine problem, and a worse safety record. It's in your shampoo, body wash, bubble bath and dishwashing liquid under names you'd never recognise. Here's what it is, what the evidence actually says, and how to find it on a label.

What is diethanolamine?

Diethanolamine is a synthetic compound made from ethylene oxide and ammonia. On its own it's rarely added to cosmetics any more. What you'll find instead are DEA compounds: DEA reacted with a fatty acid to make a creamy, foam-boosting ingredient. The best known is cocamide DEA, made from coconut oil, which is why some labels call it "coconut-derived" and leave it at that.

These compounds do 3 jobs in a product: they thicken it, they make it foam, and they stop the foam collapsing. That's why they're in almost anything that lathers.

Where you'll find it

Shampoos and conditioners, body washes and shower gels, bubble bath, liquid hand soap, shaving foam, facial cleansers, baby wash, and dishwashing liquid. It's far more common in rinse-off products than leave-on ones.

How to spot it on a label

Look for "DEA" as a suffix or prefix, or the word diethanolamine anywhere:

• Cocamide DEA (also written cocamide diethanolamine, coconut oil diethanolamide, or coco diethanolamide)
• Lauramide DEA
• Linoleamide DEA
• Oleamide DEA
• DEA-cetyl phosphate, DEA-lauryl sulfate, DEA-oleth-3 phosphate
• Diethanolamine

You'll also see cocamide MEA and cocamidopropyl betaine, which are different ingredients that do the same job. Neither carries the DEA concern; cocamidopropyl betaine has its own allergy story, which we cover separately.

Is diethanolamine safe? What the research actually says

This is the part most "toxic ingredients" lists get wrong in both directions, so here it is carefully.

The animal studies. In the late 1990s the US National Toxicology Program ran 2-year studies applying DEA and DEA compounds to the skin of rats and mice. DEA itself caused liver and kidney tumours in mice. Cocamide DEA and lauramide DEA caused liver tumours in female mice. In rats, neither caused cancer. The researchers traced the tumours in the DEA-compound studies to free DEA present as a contaminant, not to the compound itself.

What the regulators concluded. Based on those studies, the International Agency for Research on Cancer classifies both diethanolamine and cocamide DEA as "possibly carcinogenic to humans" (Group 2B). That is the same category as aloe vera extract and pickled vegetables, which tells you it means "there is some animal evidence and we can't rule it out", not "this causes cancer in people". There are no human studies showing harm from cosmetic use.

Why the mouse result may not apply to you. DEA causes liver tumours in mice by depleting choline, a nutrient mice are unusually sensitive to. Humans handle choline differently, and the cosmetic industry's safety panel considers this the main reason the mouse finding may not translate. That's a reasonable scientific argument. It's also, you'll notice, an argument made by the industry.

The nitrosamine problem. The same issue as triethanolamine, and better established here. When DEA meets a nitrosating agent (some preservatives, and nitrite contaminants in raw materials), it can form N-nitrosodiethanolamine, NDELA, which is a recognised carcinogen and is absorbed through skin. NDELA has been found as a contaminant in shampoos and cosmetics. This is the concern regulators actually act on.

The irritation question. In the animal studies, every dose caused skin irritation and thickening at the application site. In people, cocamide DEA is a recognised cause of allergic contact dermatitis, particularly hand eczema in hairdressers, nurses and others who wash their hands dozens of times a day.

What the rules are

• European Union: diethanolamine itself is banned as a cosmetic ingredient. DEA compounds such as cocamide DEA are allowed, but the free DEA in them is capped at 0.5%, and they can't be used in products where nitrosamines could form.
• California: cocamide DEA has been on the state's Proposition 65 list of chemicals "known to cause cancer" since 2012, based on the mouse studies. Products sold there must carry a warning or be reformulated; most big brands reformulated.
• Cosmetic Ingredient Review (US industry panel): DEA compounds are "safe as used" provided they're non-irritating, free DEA is kept low, and they're not combined with nitrosating ingredients.
• South Africa: there's no specific DEA restriction in SA cosmetic regulation. Products made for the EU market will meet the EU rule; products made locally or imported from elsewhere may not.

So should you avoid it?

Our honest reading: the cancer risk from a shampoo you rinse off in 30 seconds is small and unproven in humans. The reasons to avoid DEA compounds anyway are practical.

1. You don't need it. It's a foam booster. Foam doesn't clean anything; it just feels like it does.
2. You can't see the contaminants. The free-DEA and nitrosamine levels in a bottle depend on the manufacturer's quality control, and nothing on the label tells you.
3. If you have eczema or sensitive hands, it's a documented allergen and worth cutting first.
4. It adds up. Shampoo, body wash, hand soap, bubble bath and dishwashing liquid, daily, for decades. No safety limit was set with that total in mind.

Start with whatever touches your skin most often, which for most people is hand soap and body wash. Swap products as they run out rather than binning the bathroom cabinet.

Frequently asked questions

Is cocamide DEA natural because it comes from coconut?
No. The fatty acid comes from coconut oil; it's then reacted with synthetic diethanolamine. "Coconut-derived" on a label is accurate and misleading at the same time.

Is DEA the same as TEA?
Same family (ethanolamines), different molecules. TEA is mostly used as a pH adjuster and emulsifier; DEA compounds are foam boosters. DEA has the stronger animal cancer evidence, which is why the EU bans DEA itself but not TEA.

What about cocamide MEA?
The monoethanolamine version. It wasn't carcinogenic in the same animal tests and is generally considered the safer substitute, though it's still a synthetic surfactant and can irritate.

Is it in baby products?
Sometimes, especially in bubble bath and "tear-free" washes. Check the label.

The sources

• National Toxicology Program (1999). Toxicology and carcinogenesis studies of diethanolamine in F344/N rats and B6C3F1 mice (dermal studies). Technical Report 478. View →
• National Toxicology Program (1999). Toxicology and carcinogenesis studies of lauric acid diethanolamine condensate (dermal studies). Technical Report 480. View →
• Fiume MM et al. (2013). Safety assessment of diethanolamides as used in cosmetics. International Journal of Toxicology 32(3 Suppl):36S–58S. View →
• Fiume MM et al. (2017). Safety assessment of diethanolamine and its salts as used in cosmetics. International Journal of Toxicology 36(5 Suppl 2):89S–110S. View →
• International Agency for Research on Cancer. Monographs Volume 101: Diethanolamine and coconut oil diethanolamine condensate (Group 2B). View the classification list →

Find out more

• Cocamidopropyl betaine: the "allergen of the year" that probably isn't
• Triethanolamine: dangers, side effects and is it safe?
• Methylisothiazolinone (MI): the preservative behind the allergy epidemic
• Phenoxyethanol: the paraben replacement, and is it safe?
• Commercial soap ingredients: what's really in your bottle
• Harmful ingredients to watch out for in body lotions

This article is general information, not medical advice. If you have a skin reaction that doesn't settle, see a doctor or dermatologist.

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