October 03, 2018
SLS and SLES
by Diana E. Perez
When we use personal hygiene products to wash up—such as shampoos, toothpastes, body washes and other items—many times we have the expectation of that foaming effect and the "clean" feeling afterwards. They seem to feel like the only way we know that we are indeed clean. But the truth is that the bubbling during and smooth dryness after a wash is not necessary to actually get clean. This can be achieved without that effect (or a great deal of it).
That lathery, bubbly effect you find in many cosmetic and cleaning products comes from the surfactants Sodium Lauryl Sulfate (SLS) or Sodium Laurel Ether Sulfate (SLES). They come by other names too, so it is prudent to keep an eye out for them when you read labels.
A little bit about... SLS and SLES:
But what are these chemicals in your products? Well, to simply: SLS and SLES are chemical compounds that help to remove oils, dirt and grime more easily when rinsing because of the emulsifying effect of the chemical while it lathers up. They can be plant-based or petroleum-based, grabbing the lauryl alcohol from the base-item then treating it with several more chemicals to change it and stabilise it for use. Both of these are well-documented to be irritants to human and animal.
What is the difference between SLS and SLES? They are made in a very similar way. The biggest, notable difference being that SLES undergoes a process called ethoxylation. The effect is that it makes SLES less of an irritant than SLS, which is why you might find it more often in bath and beauty products.
A little bit about... the controversy:
In learning about these chemicals, it is inevitable that you will come across sources that make strong claims against the use of SLS and SLES and strong statements in support of their use. It can get confusing with the direct contradictions. But let's take it a little at a time.
Are SLS and SLES toxic or cancer-causing? This is an understandable first-concern. As far as most regulatory government bodies go, these chemicals have not been shown to cause cancer with the small amounts you would be exposed to from person products and regular use. It is important to note though, that in the process to make SLES a harmful byproduct called 1,4 dioxane becomes present. This is a compound considered to be a probable carcinogen but is not required by some regulatory offices to be removed, likely because it is present in such small quantities that it isn't considered to have a strong enough effect. Still, there are not enough studies that observe long-term effects of exposure in small quantities to know for sure. What we do know for certain is that SLS and SLES are irritants to your skin and eyes even in the small daily exposure of washing.
Are they bad for the skin? SLS and SLES are used to target oils and grime, but remember that your skin has natural oils (and other things) that it needs to keep itself and the rest of the body healthy. Removing the oils from your skin will leave it unprotected and dry. Everyone's skin is different, but if you happen to have more sensitive skin—or simply a few days with higher sensitivity—then SLS and even the gentler SLES can dry out and irritate your skin too much, causing or exacerbating other skin-health complications.
Whether you have regular skin and don't want to risk the effects of SLS and SLES or you have sensitive skin and it would be best to avoid these chemicals, there are products you can use without these in them that will definitely get you clean without all the bubbles. Keep an eye on the ingredients' list. If you are looking to avoid these, sometimes they use terms like "made from coconuts" or "comes from palm oils", which are just other ways of saying plant-based SLS or SLES. If you aren't certain that something will work for you, it is always best to get the product information and ask your doctor for personalized advice.
Enjoy your natural, health-conscious alternative!
Therapeutic Goods Administration (on SLS and similar surfactants)— https://www.tga.gov.au/book-page/27-sodium-olefin-sulfonates
US Department of Health and Human Services (Health Studies)— https://hpd.nlm.nih.gov/cgi-bin/household/brands?tbl=chem&id=78&query=sodium+lauryl+sulfate&searchas=TblChemicals
US National Library of Medicine (Toxicity Summary)— https://toxnet.nlm.nih.gov/cgi-bin/sis/search2/r?dbs+hsdb:@term+@rn+151-21-3
Biodegradation of SLS with aquatic microorganisms— https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=15&ved=2ahUKEwjq1ozHoefdAhVFQq0KHciXBecQFjAOegQIARAC&url=http%3A%2F%2Fjhiph.alexu.edu.eg%2Findex.php%2Fjhiph%2Farticle%2Fdownload%2F137%2F114%2F&usg=AOvVaw0KaGaDNkmdDjVb10ZvcJqJ
Centers for Disease Control and Prevention (on SLS)— https://www.cdc.gov/niosh/ipcsneng/neng0502.html
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