SODIUM LAURYL SULFATE

Name / description

Sodium Lauryl Sulphate (SLS); Sodium Dodecyl Sulphate

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Function(s) of this ingredient in cosmetic products

CLEANSING

Cleans skin, hair or teeth

DENATURANT

Makes cosmetic ingredients and products unpalatable (eg alcohol due to bitter substances)

FOAMING

Forms foam by trapping air (or other gases) in a liquid

SURFACTANT - CLEANSING

Surface-active agent to clean skin, hair and / or teeth

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Origin

synthetic/plant

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Occurrence in cosmetics

Shampoo, shower gel, bathing foam, toothpaste etc

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Occurrence in other products

Cleaning products, liquid detergent, hand washup product

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Background information on use in cosmetics

Sodium lauryl sulphate is an anionic surfactant (detergent) from the group of fatty alcohol sulphates. Chemically speaking, anionic surfactants have a negative charge through a sulphate, carboxyl or phosphate group; the latter determines the hydrophilic (water-soluble) component of the molecule. Anionic surfactants are above all commercially available as salts with sodium (INCI: sodium), potassium (INCI: potassium), magnesium (INCI: magnesium), monoethanolamine (INCI: MEA) etc and account for the largest part of synthetic surfactants. Fatty alcohol sulphates are characterised by a strong cleaning power, an excellent foam formation and an easy thickening capacity with common salt. Sodium lauryl sulphate has a good foaming, wetting and washing ability with a high cleaning and emulsification effect and is, therefore, frequently used as emulsifier in ointments and lotions as well as in cleaning products, more particularly in liquid detergents and washing up liquids. Sodium lauryl sulphate is an odourless, white, crystalline solid, which is easily solvable in water. Surfactants are so-called detergent substances and have a major significance in cosmetics for the cleansing of the skin and hair. Surfactants are substances which, based on their molecular structure, are able to reduce the surface tension of a liquid. In this way it is possible that two actually not mixable substances, such as oil and water, can be finely mixed. Because of their properties, surfactants have manifold uses in cosmetics: they can cleanse, produce foam and act as emulsifiers and mix substances with one another. In shampoos, shower gels and soaps, surfactants are, for instance, used to wash fat and soil particles with water off from the body. Surfactants are also used in toothpaste. Here they promote during tooth cleaning the rapid and full dissolution and distribution of the paste in the mouth. The surfactants used in cosmetic products are primarily produced synthetically on the basis of vegetable raw materials. Surfactants are often used in combination to equally meet all desired requirements – like dissolution of soil and formation of foam in combination with a good skin tolerance – in the best possible manner. Through a skilled combination of a surfactant – viewed on its own – with unfavourable skin tolerance but a very good soil removal property with a very mild, skin protecting surfactant altogether a product with good cleansing properties and the same good skin tolerances is obtained.

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Why are we talking about it?

Sulphates are accused of being irritating to the skin and eyes. The facts: Sulphates have been widely evaluated by international expert committees (Europe, USA), which each time have confirmed the safety of these ingredients in cosmetic formulations. This is also the conclusion of the European Medicines Agency for their use in topical medicines (application to the skin). Taken individually, sulphates do indeed have an irritant potential. This is taken into account when formulating a product. The concentration of sulphates can thus be reduced by combining them with each other or with other surfactants which act in synergy. Certain ingredients can also be added to the formula to ensure a better tolerance profile. A cosmetic product is more complex than the sum of its ingredients. It is the irritant potential of the finished product that counts, and this is assessed by tolerance tests (skin and eye) before the product is placed on the market. Key points to take away: At the concentrations usually used in cosmetic products, sulphates are not irritating to the skin or eyes. Their use is well controlled, and the tolerance of the finished product is systematically validated by tests. For rinse-off products, following the precautions for use written on the product allows for a safe use.

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Further information

For the clarification of a suspicion of a contact allergy this substance can be routinely tested in the epicutaneous test at the dermatologist.

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Belongs to the following substance groups

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Regulating cosmetics

Cosmetics Ingredients are subject to regulation. Please note, different regulations may apply to cosmetic ingredients outside the EU.