How to tell the difference and which is the safer one?SLS & SLES. They sound similar and are even closely related but are very different. At the end of this 5-minute tutorial, you should be able tell one from the other, and choose the right product for yourself - without having to do a PhD in Chemistry. Read on!
Where are they used?
SLS & SLES, usually separately, are widely used in shampoos, toothpastes, shower gels, face washes and many other personal care products. They are both workhorses of the cosmetics industry. The INCI names of the two are very close, see below carefully to see which one is in your product. If you missed our 1-minute tutorial on reading ingredient lists, you can read it here
SLS = sodium lauryl sulphate
SLES = sodium laureth sulphate
OK, how are they similar?
- Both are surfactants – i.e., help lather, cleanse oil and soil better than just water, from any surface
- Both are derived from coconut or palm kernel oils - more the latter, these days
- Both are sulphates. Sulphate-free formulations will therefore have neither. We will review sulphate-free formulations in another post
- SLES is derived from SLS, by the addition of ethylene oxide. This is called ethoxylation.
- Neither of them is a natural compound. Don’t fall for the “derived from coconut oil” stories.
- Prima facie, both are safe for use in cosmetics. BUT, there are some key issues with SLS, as we will see below.
Note: We like the Cosmetic Ingredient Review as an objective source of knowledge on whether stuff is safe or not
However (there is always a however):There are some important MAKE-OR-BREAK issues with SLS, which is why we don’t like to use SLS in any of our upcoming products:
- SLS is a known skin sensitizer – it may cause redness and irritation in some people.
- At high enough concentrations, it will irritate most people.
- SLS is an aggressive surfactant. Much like antibiotics that kill good bacteria in our body, SLS cleans out even essential oils and lipids from the skin. It doesn’t mean SLS (or antibiotics) is unsafe, it just means we shouldn’t use them unnecessarily.
- The above issues are known to get worse in younger, more tender skin
So, is SLES safe?The ethoxylation of SLS is known to turn it extremely mild, as a result of which SLES is even fit to be used in baby shampoos. We love to use SLES in our products as it is mild, safe, effective, and works well with other ingredients. Its safety as a cosmetics ingredient has been established beyond doubt.
Got it. Anything else I need to know?Two questions remain, for the advanced readers amongst you:
- Are sulphate-free formulations (neither SLS nor SLES) necessarily better?
- Should I be worried about 1,4 dioxane?
- We will answer both these questions in a subsequent post. Do keep the feedback coming. Cheers, Be Good!
Appreciate the clarification…
Thank you so much….It was immensely useful and informative.