Bad Ingredients in Hair Shampoo

Written by malinda zellman
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Bad Ingredients in Hair Shampoo
Many people do not realise that shampoo may contain harmful ingredients. (shower series 2 image by Alexey Stiop from

Shampoos contain some ingredients with the potential for hair loss or health hazards. Manufacturing byproducts become ingredients in shampoo that you will never find on the ingredients list. These byproducts may act as potential carcinogens or neuro depressants, creating toxins in both the liver and kidneys. The actual, listed ingredients almost always include sodium laureth sulphate, a suspected carcinogen that may cause hair loss and/or eye irritation, and similar ingredients. Furthermore, some shampoo ingredients can react to other products chemically, forming other potentially harmful substances.

Carcinogenic Manufacturing Byproducts

Two potentially harmful substances present in shampoos will never show up on the ingredients label: formaldehyde and 1,4-dioxane. As manufacturing byproducts, labelling of them is not required. The Environmental Protection Agency (EPA) shows formaldehyde as a probable human carcinogen.

Dermal exposure happens when you wash your hair. The EPA also reported as early as 1959 that, "Neurological symptoms were reported in the fatal case of a worker exposed to high concentrations of 1,4-dioxine through both inhalation and dermal exposure." 1,4-dioxane depresses the central nervous system. Noncancerous effects of 1,4-dioxine exposure indicated in studies are liver and kidney toxicity in humans and laboratory animals.

Even so, according to the Personal Care Products Council, exposure to these two byproducts found in such low concentrations as are present in shampoo is considered safe. Data is mixed, therefore, on the dangers found in these byproducts.

Bad Ingredients in Hair Shampoo
We all want beautiful, healthy hair. (hair image by Pavel Vlasov from

Sodium Laureth Sulfate

Sodium laureth sulphate (SLES) and its chemically close "relatives" endure constant scrutiny as a possible carcinogen and as a cause for hair loss. Few shampoos have no SLES in them. SLES acts as the detergent and foaming agent in shampoos. A similar ingredient, sodium lauryl sulphate (SLS) can cause eye irritation because of its harshness.

<p> recommends you avoid all these ingredients in shampoo: sodium lauryl sulphate, ammonium lauryl sulphate, ammonium laureth sulphate, ammonium xylene sulfonate and TEA lauryl sulphate. For users of dandruff shampoos, they recommend avoiding sulphur and selenium sulphide.

Bad Ingredients in Hair Shampoo
Most people assume their shampoos are safe. (shampoos and shaving foam lined up image by Georgios Alexandris from


Diethanolamine (DEA) and triethanolamine (TEA) are used as solvents, emulsifiers and wetting agents in shampoos. According to a 1998 study by the National Toxicology Program (NT), they "found an association between the topical application of diethanolamine (DEA) and certain DEA-related ingredients and cancer in laboratory animals."

Nitrates are used in shampoos to preserve the shampoo formula. When DEA or TEA reacts with the nitrates in the shampoo, a cancer-causing agent forms. A shampoo with bronopol as an ingredient in it may produce this reaction. Therefore, you may wish to avoid shampoos with bronopol.

Bad Ingredients in Hair Shampoo
Some shampoos may cause hair loss. (bad smily image by David Büttner from

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