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Sodium lauryl sulphate PDF Print E-mail

Sodium lauryl sulphate (SLS) is a surfactant widely used for home products and in industrial applications. It is used in detergents (dishwashing liquids, laundry liquids), carpet cleaning products, toothpaste, mouthwashes, cosmetics (such as moisturisers and shaving cream), hair products (especially shampoos), pharmaceuticals and food. SLS is an anionic surfactant which acts as an emulsifier, that is, it binds to oil and suspends it in solution. In cleaning products this allows oil and grease to be washed off by water and SLS can also assist lathering, while in other products it maintains the product's stability. In food it is used as an emulsifier and whipping agent (e.g. dried egg products) as well. It also appears in insecticides as a wetting agent, that is, it helps the insecticide disperse evenly over the plants' surfaces.

Related chemicals are sodium laureth sulphate, ammonium lauryl sulphate and ammonium laureth sulphate. The laureth sulphates are the basic compound (called a linear alkyl surfactant) plus ethylene oxide, and are known as ethoxylated surfactants. They are all sulphates derived from lauryl alcohol (dodecanol).

Health effects
SLS is moderately toxic by ingestion and is a mild allergen and respiratory irritant. The jury is still out, but it may be mutagenic and teratogenic. These sulphates can dry out the skin and may lead to skin reactions. They can be eye irritants and may cause damage by interfering with formation of protein in the eye. There is some evidence that they may damage the hair follicle, which means hairs are replaced more slowly (i.e. thinning hair).

Environmental effects
These chemicals may end up in waterways after being washed down the drain. The potential for bioaccumulation in aquatic organisms is moderate.

Use soap where possible for body and hair. In hard water you can use vinegar or lemon juice for the hair. Be careful when using hair products not to swallow any and keep it away from your lips and out of your eyes. Rinse your hair, hands and the rest well after use. Don't swallow your toothpaste! If you are sensitive to these sulphates then read ingredient labels carefully---in food and cosmetics the manufacturer is obliged to list them. For laundry, use the minimum amount and extra rinses.

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