SLS vs SLES

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 read, 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.

SLS = Sodium Lauryl Sulphate
SLES = Sodium Laureth Sulphate 

OK, how are they similar?

  1. Both are surfactants – i.e., help lather, cleanse oil and soil better than just water, from any surface
  2. Both are derived from coconut or palm kernel oils - more the latter, these days
  3. Both are sulphates. Sulphate-free formulations will therefore have neither. SLES is derived from SLS, by the addition of ethylene oxide. This is called ethoxylation. 
  4. Neither of them is a natural. Don’t fall for the “derived from coconut oil” stories. 
  5. Prima facie, both are safe for use in cosmetics. BUT, there are some key issues with SLS, as we will see below.

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 products:

  1. SLS is a known skin sanitizer – it may cause redness and irritation in some people. 
  2. At high enough concentrations, it will irritate most 
  3. 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.
  4. The above issues are known to get worse in younger, more tender skin

In short, stay away from SLS if you can.

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. 

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