Diethanolamine (DEA) is a common wetting agent used in shampoos, skin care and cosmetics. It creates a rich lather in shampoos and produces a nice consistency in skin care. On its own, it is harmless, but when combined with other ingredients in a shampoo, cream or lotion, it reacts to produce nitrosodiethanolamine (NDEA), an extremely carcinogenic compound which can easily be absorbed through the skin. It has been linked to stomach, bladder and intestinal cancers.

Avoid products with these ingredients:

• Cocamide DEA or Cocamide Diethanolamine
• DEA Lauryl Sulfate or Diethanolamine Lauryl Sulfate
• Lauramide DEA or Lauramide Diethanolamine
• Linoleamide DEA or Linoleamide Diethanolamine
• Oleamide DEA or Oleamide Diethanolamine
• Any product containing TEA or Triethanolamine

Skin Deep ranks this ingredient with a safety score of 8 (high hazard) and rightly so.