PEGy - nebezpečná součást kosmetiky nebo nesmyslná demonizace?

PEGs - a dangerous part of cosmetics or senseless demonization?

What is it?? Structurally: PEG = Poly E thylene G lycol. That is, several ethylene groups attached to the glycol molecule thanks to a process called ethoxylation .

This structure is then used to bind to other molecules to modify their functions. This creates, for example, PEG-100 Stearate or PEG-40 Hydrogenated Castor Oil and many others. Such "PEGs" have a lot of functions, it depends on the specific species. These are mostly surfactants and emulsifiers, i.e. surface-active substances in general. They can add a pearly effect (for example to shampoos) or foam (which is why they are used for cleanser formulations).

Let's start with the question Why did PEGs come about? Simply to improve the properties of existing cosmetic ingredients! For example:

Let's look at the surfactant - the substance used in shampoos - Sodium Lauryl Sulphate (SLS). Putting aside the fact that it's trendy to avoid sulfates, SLS reacts with hard water to create calcium residue. Which, of course, we don't want in our hair. Nevertheless, this substance is so important that instead of looking for a replacement, we can make do with its modification - using PEG. We thus obtain Sodium Laureth Sulphate (SLES) with gentler cleaning properties and even better solubility in water.

Are you afraid of dangerous carcinogens in PEG substances? You don't have to .

Yes, PEGs are made from ethylene oxide, which is a carcinogenic substance. However, it will no longer enter cosmetics because it is a gas and the resulting PEG is a liquid. Mainly thanks to rigorous laboratory methodologies, there are ways to verify its content, so we don't have to worry.

But what can happen during the ethoxylation process is that instead of the ethylene oxide molecule binding to our substance, it binds to another ethylene oxide molecule. This gives us 1,4-dioxane. This has been identified as a possible carcinogen in mice by oral use (drinking/eating), which gives us the possibility that it would also be a human carcinogen. What now? Could this 1,4-dioxane be in our shampoos and shower gels?

Theoretically yes, trace amounts can be found there and the legislation gives maximum permissible limits (which are super low). In the shower, due to the steam pressure, 1,4-dioxane can evaporate and we can inhale the super low amounts. Or we don't have to. And as for absorption by the skin - substances soluble in water are poorly absorbed, so no worries.

But what does the mouse study tell us? "possible carcinogen in mice when used orally". So don't drink the shampoo or shower gel! :D 

Back to blog

Leave a comment