9 September 2021




TOosmetic chemist and creator of her own brand, Sharova Pro Anna Sharova – about how SLS differs from SLES, are there natural sulfates and are they really as harmful as it is commonly believed?

Anna Sharova

Anna Sharova

Cosmetic chemist and creator of her own brand, Sharova Pro

What is SLS

The main role of sodium lauryl sulfate (SLS) is excellent foaming at a relatively low cost of the component. For example: the SLS toothpaste will foam gorgeous, which means it will clean the enamel and fight plaque. Toothpaste without SLS (it is replaced by sodium lauryl sarcosinate) does not foam so well, which means that the enamel does not clean so well: it seems to have brushed my teeth, but there is no feeling of cleanliness.

Do not forget that SLS is the main working component of most household chemicals. They foam and remove dirt thanks to sodium lauryl sulfate.

What is the difference between SLS and SLES sulfates

Sodium Lauryl Sulfate (SLS) is a white powder containing 100% active ingredient. Sodium Laureth Sulfate (SLES) is traditionally a 70% paste. But the concentration can be less, about 30%, it all depends on the specific brand of sodium laureth sulfate.

It is not difficult to test the effect of sulfates on the skin. And this has been repeatedly done by large corporations (for example, the BASF concern) and independent expert organizations (The Cosmetic Ingredient Review). But the complexity of all patch tests is that sulfates are tested in large volumes and are on the skin for a long time, resulting in irritation. For example, to evaluate the effect of SLES, sulfate was on the skin for up to 48 hours, while its concentration in an aqueous solution reached 30% – this is not the case in cosmetics.

In addition, the aggressiveness of the effect of surfactants on the skin (SLES and SLS) drops several times when combined with soft co-surfactants, and this is how technologists create their formulations.

In the joint formula, the drying effect of SLES is always minimized, leaving only an indicator of customer-friendly foam.

If we compare these two components, then SLS will be more aggressive, but, in fairness, I note that sodium lauryl sulfate is not often introduced into cosmetics – it is replaced by SLES.

Is the SLS Danger True or Myth?

In general, the danger of SLS is a myth (read about 33 beauty myths here). Otherwise, it would have long been included in the list of ingredients prohibited for use, and at least Japanese companies would have stopped using it in their beauty formulas.

In addition, many oral hygiene products (toothpastes, rinses, foams for express cleaning of enamel) contain SLS as a foaming agent. Bringing an oral hygiene product to market is one of the most challenging procedures in terms of volume and severity of tests. The manufacturer receives state registration (testing here is more difficult and longer than, for example, when receiving a cosmetic declaration). One of the mandatory documents that a company acquires during state registration is the clinical safety protocol. If SLS in oral hygiene formulations did real harm, the manufacturer would never get a positive protocol. Again, SLS is usually used at a safe concentration of 0.5-5% specifically in liquid foaming agents (not very common now), shampoos, shower gels, pastes, dry bath bombs and shampoos.

Where did the information about the insecurity of SLS come from then?

There are several reasons. The first is to exaggerate the problem with completely misinterpreted test results, when all possible sins are attributed to the shower gel. And the second is the development of another business – “green cosmetics” without SLES and SLS. The more this part of the market develops, the more guilty companies using SLES will feel. However, do not forget that there are brands that position themselves as 100% eco, but continue to buy the same SLES for production. We all move in the same perfumery and cosmetic world and we have common suppliers. Some companies claim that they use natural SLES and SLS, but there are only two options: to produce sulfates 100% synthetically or partially natural.

It is also believed that sulfates have a cumulative effect. But this is speculation too. I have not seen such studies. The initial irritant effect is minimized thanks to a well-designed formula using mild co-surfactants.

Who Should Avoid SLS?

I do not advise using products with sulfates for intimate hygiene and cosmetics for pregnant women here), newborns and children up to 3-6 years old. Although I have met SLES in children’s cosmetics (not SLS!). But the dosage is certainly significantly lower than in adult products. For example, in an adult shower gel, the concentration of sulfate is 5-9%, and in a child’s gel – up to 3%.

Separately, I will say about hair products.

This is an eternal topic, but my opinion is that clients with very high oily scalp and increased hair fragility should avoid shampoos with sulfates and choose sulfate-free shampoos (I’m proud of ours from SharovaPro!).

But here, too, everything is very individual, taking into account the presence of co-surfactants and the peculiarities of the formulations. But dry shampoos with SLS – for me, a definite “no”!

I told you more about other ingredients in cosmetics. here