TEA is a skin irritant and may cause dermatitis. TEA causes allergic reactions including eye problems, dryness of hair and skin, and could be toxic if absorbed into the body over a long period of time.

DEA (diethanolamine) and DEA compounds are used to make cosmetics creamy or sudsy. DEA also acts as a pH adjuster, counteracting the acidity of other ingredients. DEA is mainly found in moisturizers and sunscreens, while cocamide and lauramide DEA are found in soaps and shampoos.

These ingredients function as emulsifiers or foaming agents. They are hormone-disrupting chemicals known to form nitrates and nitrosamines, in conjunction with other chemicals present in a product. A Federal government study says that DEA and DEA-based products have been shown to greatly increase the risk of cancer, especially liver and kidney cancer. TEA is a skin irritant and may cause dermatitis. TEA causes allergic reactions including eye problems, dryness of hair and skin, and could be toxic if absorbed into the body over a long period of time.

According to organizations such as Safer Chemicals, Campaign for Safe Cosmetics, and the Environmental Working Group, various substances used in hair products could be considered unsafe. Parabens, found in some shampoos and conditioners, have been linked to breast cancer, while ethanolamine compounds (DEA, TEA, MEA), found in hair dyes, shampoos and conditioners, are linked to organ system toxicity.

Links

http://www.safecosmetics.org/get-the-facts/chemicals-of-concern/products/hair/
https://www.ewg.org/skindeep/#.WnCOeWnwZhE