Ingredient Uncovered: Sodium Lauryl Sulphate

I’m going to starting delving into various different ingredients commonly used in cosmetics and personal care products to try and learn in more depth about what we are putting on our skin daily. I’m starting with the most common – the ones that you’re almost guaranteed to see listed on the back of a hell of a lot of the products you use (unless of course you’re leaps ahead of me and have already junked your chemical ridden concoctions for more natural alternatives).

Culprit number one is Sodium Lauryl Sulphate.

Sodium Lauryl Sulphate (SLS) is a surfactant used in many cleaning and hygiene products. In scientific terms a surfactant is a wetting agent – a chemical which allows the easy blending of liquids. In layman’s terms it’s what makes things “froth up”.

SLS and its sister chemical Sodium Laureth Sulfate (SLES) are used in a variety of common household products.  Whenever there’s a need to remove oily stains and residues you’ll likely find SLS in the ingredients list because of its ability to work up a good lather. It’s found in high concentrations within industrial products such as engine degreasers and floor cleaners, and lower concentrations in cosmetic and hygiene products such as toothpastes, shampoos, bubble bath, shower gel and shaving foams – anything which we expect to lather up.

Seriously, I hear you ask? We use the same thing on car engines as we do in our mouths? That doesn’t sound good.

SLS has had some bad press for its propensity to irritate the skin and there has been speculation that SLS could be carcinogenic, although this has not been proven by official studies. However it has been proven that SLS is an irritant based on studies which revealed that when exposed to SLS for prolonged periods of time (as little as one hour), skin becomes significantly irritated.

SLS and skin irritation

The Journal of the American College of Toxicology reported in 1983 that

A Draize test of a product containing 5.1% Sodium Lauryl Sulfate caused mild irritation and products containing 21% were severely irritated with no rinse and mildly irritated when rinsed.
Acute animal skin irritation studies of 0.5% to 10% Sodium Lauryl Sulfate cause slight to moderate irritation. Applications of 10% to 30% caused skin corrosion and severe irritation. Solutions above 20% were highly irritating and dangerous.

So far so NOT good!  How can a product which tests have proven is an irritant (even at low concentrations) be routinely added to so many of our cosmetic and personal care products?  And often appearing at the top of ingredients lists, suggesting considerable concentrations, may I add.

Although the above results suggest that the chance of irritation is curbed be rinsing off products containing SLS immediately, what really disturbed me was that the report states that SLS is in fact highly absorptive and that other studies have even revealed deposits of SLS in the heart, liver, lungs and brain. SLS cannot be metabolised by the liver and has a low molecular weight making it easily absorbed by the body and deposited in our vital organs.

Scary stuff!

In absorption, metabolism and excretion studies Sodium Lauryl Sulfate had a degenerative effect on the cell membranes because of its protein denaturing properties. High levels of skin penetration may occur at even low use concentration.

Still other research has indicated SLS may be damaging to the immune system, especially within the skin. Skin layers may separate and inflame due to its protein denaturing properties.

Furthermore, studies have also linked SLS to ulcers, eye degeneration, especially in children, and the corrosion of hair follicles.

SLS and Cancer

Now this is the scariest information I found on SLS. Brace yourselves!

When SLS is ethoxylated it creates SLES (Sodium Laureth Sulfate), sometimes producing a harmful compound 1,4-dioxane – a known carcinogen – and one of the principal components of the chemical Agent Orange used by the Americans during the Vietnam War to erode away the jungle canopy and expose the Vietnamese people inside.

1,4-dioxane is believed to have been principally responsible for the array of cancers suffered by the Vietnamese in the aftermath of the Vietnam War as well as genetically passing on growth defects to future generations.  It is a hormonal disrupter, mimicking the effect of oestrogen, which is thought to increase the chances of breast cancer and endometrial cancer as well as lowering sperm counts.

As a side note, I visited an orphanage in Vietnam whilst travelling in 2005 and saw firsthand many children afflicted with horrific growth defects whose parents or grandparents had been in contact with Agent Orange during the war. It was a truly harrowing experience for me and totally shocking that the effect of this chemical continues to haunt Vietnamese people today.

To conclude, I think I will be going home this evening to check the labels of my shampoo, face wash, shower gel etc. and will most likely be chucking a lot of them.

However if you are particularly attached to your favourite products which do contains SLS, I would certainly recommend that you make sure you fully rinse off the product after use so that no residue at all is left on the skin.

I should state that I’m basing the information in this blog post on various different articles I’ve read about the subject  from what I believe to be reliable sources. However I’m not a scientist, nor am I claiming that there is a direct association with this chemical and cancer as this certainly has not directly been proven. I believe it’s important to think about the ingredients of our everyday products however and I would urge anyone to do their own research and come to their own conclusions on the topic. Some of the articles which I read to gather this information are listed below for your reference.

Natural health information – sodium lauryl sulfate

Natural health information – JACT report on SLS

David Suzuki – chemicals in your cosmetics

Inspired Living – skincare chemicals

Blog Pharmacymix – sodium lauryl sufate carcinogen in your shampoo

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3 thoughts on “Ingredient Uncovered: Sodium Lauryl Sulphate

  1. This is very interesting, I’ve just been working on my site to discuss these same issues and highlight SLS as a concern. Love the post and the additional resources.

  2. Interesting post! Do you have URLs for the research you quoted? I’d like to read the article(s)

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