SLS (Sodium Lauryl Sulphate) and Natural soap are both surfactants - they change the surface tension of water so that dirt can be cleaned away. But they are not equal.
- Natural soap is the original way of making soap - by combining oils or fats with lye, without further processing.
- Industrial bar soap - cheap bar soap - is the pure soap extracted from natural soap - which is only cleaning and not moisturising, so it should not be used on skin.
- SLS is different - it is a synthetic cleaning agent originally developed for use as an engine degreaser, but is now used in bar soaps, liquid soaps, shampoos and toothpaste.
Note: At Clean Up Atelier, you will never find SLS, or any variant of it, in any of our products.
What are SLS and SLES?
Before SLS was developed, the only man-made surfactant that existed was natural soap. During World War I there was however a shortage of soap, which spurred innovation for an alternative. SLS was first used as an engine degreaser, before being used in shampoos in the 1930’s.
Now the sciency stuff. SLS is derived from either petroleum, coconut oil, or palm kernel oil. It is produced from petroleum via the ‘OXO process’, or from coconut or palm kernel oil via the ‘Ziegler process’. In both cases, fatty acids are extracted and converted to fatty alcohols, then sulfonated to become a crystalline salt. SLS can then be converted to SLES (Sodium Laureth Sulphate) via ethoxylation.
Despite so much processing, SLS and SLES are very inexpensive, mainly because they are so effective that even a small amount has a heavy cleaning effect. Even if produced from coconut or palm kernel oil, after undergoing so many processes with toxic chemicals such as sulfuric acid, SLS and SLES are no longer considered natural. All forms of SLS are considered synthetic detergents - or ‘syndets’ for short.
SLS and SLES are very foaming. If you have a product which produces a lot of foam easily, it probably contains SLS or SLES. The public has come to equate foam with cleaning power - but unfortunately this isn’t true! While foam is fun, it is only showing a substance’s ability to stick to water. Different oils have different sticking ability to water, but the soap that is made from these oils cleans just the same. Dishwasher tabs, for example, produce no foam, and are highly effective at cleaning.
When cleaning vertical surfaces, foam can help to keep the soap in place for longer. When shampooing, although it is not necessary for cleaning, it can help hold the soap to your head, and create space between hairs, which gives the soap better access to every individual hair as well as your scalp. For washing skin, foam is not necessary, but a little is still nice to have. Natural soaps do not foam as much as SLS and SLES, but still foam up enough to get between hairs, and to pleasantly stick to skin.
Why You Should Avoid SLS
SLS is just too cleansing. It is very aggressive against oils. Oils deep in your skin will be stripped away, not just the outer layer of oils. SLS is also so effective that it cannot be paired with oils which can replace your skin’s oil barrier. If the oils from even deep in your skin are removed, and nothing is immediately provided to replace these oils, it is like having bricks with the mortar taken out - you skin will lose water through evaporation, your skin is exposed to irritants from the environment, and your skin cells, the bricks, can just flake away. If your skin is stripped of all its oils, your body can have a range of reactions, such as quickly overproducing sebum, or an inflammation reaction. Many skin issues can be solved by not stripping so much oil from your skin when washing, and quickly replacing those oils with a thin layer of new oils, as natural soap does.
SLS is used, for example, in nicotine patches to ‘neutralise’ oil in the skin, which allows the nicotine to be delivered more easily. This has been found to lead to a significant impairment of the skin barrier under the patch and rashes are common.
Should Everyone Also Avoid SLES?
SLES is the less aggressive version of SLS. While SLES strips a lot less oils out of your skin, it can however contain a toxic by-product ‘1,4-dioxane’, which is not always filtered out during the manufacturing process. Thinking purely of skin health, while I would not necessarily oppose SLES in a product which also contains caring oils which will rebuild your skin barrier, I feel that it is best to avoid this ingredient altogether due its possible toxic contaminant. Considering the fact that SLES is most likely derived from petroleum or palm kernel oil, and is produced using such toxic chemicals, this ingredient is not sustainable and is not considered natural - which I cannot support. I also would not support a product containing SLES which is packaged in plastic, contains microplastics such as beads found in shower gel or facial cleanser, or contains other petroleum-based ingredients such as silicone.
Can I live without SLS and SLES?
Yes! There are plenty of products that do not contain SLS or SLES. For a start, natural soap will clean your skin effectively, and replace your skin’s oil barrier. Natural soap is all natural, sustainable, vegan, and can even be very effective against issues such as acne. Your skin will love it! No need for plastic packaging, microplastics, or silicones.
There are new products continually coming onto the market which are SLS-free or sulphate-free. SLS- and SLES-free solid shampoo and conditioning bars are excellent for avoiding plastic packaging. There are now toothpastes in tab-form, which avoid the traditional plastic tubes and are normally packaged in glass or paper, and many are SLS-free. While trying to avoid SLS and SLES, why not also choose the most sustainable product that you can find - the future is sustainable and green!