SLS sodium lauryl sulphate in skincare

Reading Labels: SLS - So What Is That Exactly?

What is SLS?

Sodium Lauryl Sulphate (SLS) and Sodium Laureth Sulfate (SLES) are commonly found in all sorts of cosmetics, cleansers, shampoos and detergents. They act as surfactants, detergents and foaming agents. Surfactants are often helpful in skin and particularly cleansing products as they loosen and emulsify oils and fats, allowing them to be washed away.

 Some sort of  surfactant is  used in most forms of cleansers and many are  gentle and effective for most skin types.   However, SLS has been shown to cause eye or skin irritation. And there is very robust scientific evidence that SLS is a serious skin irritant. It disrupts the natural barrier function of the skin, causing trans epidermal water loss (TEWL)

So what is TEWL and why should we be concerned about it?

TEWL is when water passes up through the skin and evaporates on the skin’s surface.  This is not the same as sweating.  The skin naturally regulates the amount of water lost through our skin, but certain cosmetic ingredients can disrupt this natural regulation, causing increased skin dryness and irritation, increasing TEWL.

 Eczema and dermatitis are inflammatory skin conditions that disrupt the skin’s barrier function.  Using cleansers and moisturisers that contain SLS can increase skin irritation and longterm dryness, a real issue for eczema suffers but also of concern for anyone as SLS can actually cause these conditions to break out.  A 2005 study published in the journal Contact Dermatitis states “Sodium lauryl sulfate (SLS) induced irritant contact dermatitis” 1.   It’s a real shame that the power of big pharma continues to influence dermatologists who recommend skin care brands that contain high amounts of SLS.  The science is clear:  SLS is a proven skin irritant and should be avoided, especially if you have sensitive, dry or eczema prone skin.

 You can easily check if your skincare products contain SLS by looking at the ingredients label, where it may appear as sodium lauryl sulfate/sulphate or SLS. Despite the proven issues with it, it remains a common ingredient in some surprising skincare products and it’s one your skin really can do without.

All Oasis Beauty products are SLS free. Find out more about the studies and facts behind SLS on our Good Science pages. 


1. Long-term repetitive sodium lauryl sulfate-induced irritation of the skin - Contact Dermatitis. 2005 Nov;53(5):278-84.

 2. Skin Barrier Disruption by Sodium Lauryl Sulfate - Journal of Investigative DermatologyVolume 128, Issue 5, May 2008, Pages 1212-1219

Leave a comment