Sodium Lauryl Sulphate - Foaming Or Fuming?

Sodium Lauryl Sulphate (SLS) is widely used as a detergent in all types of foaming personal care products from liquid soap and shampoo to toothpaste.

As a detergent, SLS is used in cosmetic agents to break the surface tension of the skin which allows dirt and oil to wash away. All detergents act to dissolve the fats and oils from the skin but also strip it from the top layers of the skin. This can lead to thinning and permeability of the skin. The skin is a barrier to the outside world and by washing away the natural oils produced by the skin SLS reduces the effectiveness of this natural barrier.

The most common reaction seen to SLS containing products is a dry, flaky scalp. What many people think is dandruff can actually be a reaction to the stripping effects of SLS. Those at greatest risk of this effect are babies, those with any skin irritation such as in eczema, dermatitis, acne and psoriasis, those with thinning of the skin such as the elderly or those with dry skin. However, long term use will also affect those with “normal” skin.

A search of PubMed (an internationally recognised database of scientific papers) supported these claims. Numerous trials showed that SLS can cause skin irritation, particularly in those with atopic eczema or dermatitis, as well as increase transdermal water loss. Essentially this means that when applied topically SLS will irritate and dry out the skin.

Other research suggests that SLS can mimic the hormone oestrogen. Too much of this hormone in the body (or substances that mimic its effects) can have a disruptive effect on the reproductive system. There are a range of less harsh detergent agents such as Ammonium Laurel Sulphate that are promoted as SLS alternatives, but they may also be harmful for those at risk and still have a drying effect.

So what are the alternatives? One natural alternative is olive oil based liquid Castile soap. It can be safely used with babies, those with skin conditions, the elderly and those with sensitive or dry skin. Third Stone Botanical Lavender Shampoo is a liquid Castile based product. It is ideal for dry and damaged hair.

Coconut based cleansers are also seen as safer alternatives. Nature’s Symphony shampoo and conditioner are based on coconut based cleansers. Good products for all hair types, feedback from users of these products say the health of their hair and scalp improves with ongoing use.

Given the potential harmful effects of SLS, both known and suspected, it is one synthetic chemical that is best avoided particularly as there are good natural alternatives available.