Problem Pages

Colin Solves Your Problems 11: SLS and SLES

SLS is good at forming spherical structures

Jean writes:

The old one about SLS and SLES I have tried using products with more, allegedly, greener detergents but my skin reacts to them, itching and dryness, but when I use products with the above detergent, I don’t have a problem. Is it because , although It is claimed that SLS and SLES are harsher on the skin, the composition of the products by bigger companies, who seem to spend a lot of money on formulations, are better and more complex allowing for a gentler finished product? I have come to the conclusion that a detergent is a detergent and maybe it is best just to use a good soap made with oils and sodium hydroxide. Love your site for info, very informative. I am sick of all the scaremongering sites and wonder whether the people who write some of this stuff realise how daft they look.


Hello Jean,

This is a really interesting question, thanks for raising it. I think you have basically worked out what is going on. You’ve joined up the dots but let me fill in the picture. ┬áSLS is short for sodium lauryl sulphate and SLES is short for sodium laureth sulphate. ┬áSLS and SLES are certainly irritating to the skin, and are used in research for this very purpose. They interfere with the structure of the topmost layers of the skin making it more porous, so the water escapes too quickly and your skin gets dry.

So on the face of it they sound like a bad choice for skincare. But there is a twist. If you look at the degree of irritation they cause, it behaves rather strangely. At low concentrations you get more irritation than at higher levels. This is because the detergent molecules form spherical structures called micelles when there are enough of them. (They aren’t always strictly micelles, but there is no need to complicate things.) By mixing different detergents you can come up with blends that form micelles that are almost non-irritant to most people. So with a bit of experimenting you can make very mild formulations with theoretically very irritating ingredients.

Formulating with the products that meet the approval of the lovers of the natural is much harder work because you don’t have as many options for creating micelles. I don’t want to knock the natural product sector too much. They do provide an alternative and it is good to try different ways of doing things. But I have to say most natural products are in fact rubbish, especially ones that have been certified to organic standards. A standard written by someone who has never formulated a product is likely to be very restrictive and make it very difficult to come up with a good product, or even an acceptable product.

I don’t think your experience of them is at all unusual and I am sure that is the main reason sales of organic and natural products are falling. People still like the idea, they just don’t like the unpleasant experience of actually using them.

Soap is the main cleanser I use, but it does dry the skin a bit. Personally I put up with it because it isn’t that big a problem for me, but some people do prefer milder options and we are all different.

Thanks for your kind comments about my blog. As to whether the scaremongers realise how daft they look, I don’t know but if they don’t it isn’t for want of me telling them.

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