What is Sodium Lauryl Sulphate?

Sodium Lauryl Sulphate - SLS

Sodium lauryl sulphate (SLS) is an anionic surfactant (detergent) which is included as a foaming agent (to clean and make bubbles) in a huge variety of commonly used products. These include shampoos, soaps, face and body washes, toothpaste, washing up & laundry detergents and also industrial cleansing chemicals such as engine degreasers. There are many derivatives of SLS that can be found in commercial preparations, including sodium laureth sulphate, sodium laureth-3 sulphate, and DEA or TEA sodium lauryl sulphate. Although these derivatives may vary slightly in mildness, the general action and effects are essentially similar.

Sodium Lauryl Suplhate - Growing Concern

Recently, there has been growing concern about the widespread use of these detergents and their safety has been called into question. In this report, we will review the scientific literature available and show why it may be wise to attempt to minimise your exposure to this family of foaming agents.

A major concern about SLS is the effect that it has when used in combination with other ingredients commonly found in personal care products. SLS has the potential to react with other ingredients (e.g. 2-bromo-2-nitropropane-1,3-diol, DEA, MEA, TEA) to form nitrosating agents, which in turn can form nitrosamines, which are known to be carcinogenic.

Sodium Lauryl Suplhate - Similar names, different effects

There are several other surfactants with similar names to SLS – in particular ammonium lauryl sulphate and ammonium laureth sulphate. Although these sound very similar their molecular structure is significantly different and they do not have the same potential to irritate the skin. Also, because their molecules are larger than those of SLS, they are not able to pass through the skin and therefore cannot be absorbed into the body in the same way. Because of these differences, ammonium lauryl and laureth sulphates are considered to be milder and safer alternatives to SLS.

Effects of SLS on the Skin

SLS is commonly used in research laboratories as the standard ingredient (upon which all other substances are compared to) for irritating the skin.

A solution of just 2% SLS can increase skin thickness, cause irritation, inflammation and increase other forms of immune activity in the skin. Some shampoos can contain more than 50% SLS.

SLS can cause an increase in enzyme levels in the skin, leading to redness and swelling. It can also lead to dryness, roughness and even flaking of the skin.

Effects of SLS in the Mouth

SLS can damage the delicate mucosal membranes in the mouth, causing the separation of epithelial layers from the mucosa.

Burning and severe itching of the oral mucosa following the application of SLS containing toothpaste has been reported.

The tissue damage caused by SLS increases with increasing concentration of SLS.

Switching from a toothpaste containing SLS to one without, can lead to a statistically significant decrease in the occurrence of mouth ulcers in those with recurrent aphthous ulcers.

Effects of SLS on the Eyes

SLS can penetrate the cornea of the eye (even if absorbed through the skin), accumulate readily and is released slowly. These effects are greater in younger individuals. A single drop of SLS can remain in the body for 5 days, so if you wash a child’s hair more than once a week with a SLS containing shampoo, there will be constant levels of SLS present.

A solution of 1.3% SLS can reduce the rate of healing in the eye.

Variations in response to SLS

There is substantial inter-individual variability in the response to SLS – not everybody will be affected to the same extent.

Younger individuals are more susceptible to the effects of SLS.

The effects of SLS become more harsh with increasing temperature. This is important to note, as most people prefer to wash in warm water.

article source: Greenpeople