Beauty · Science

Sulphate free

A while back I wrote this about the advantages (or lack thereof) of choosing paraben free products. Every now and then you see articles encouraging you to only buy things that are free from certain chemical, or products boasting about not having those chemicals in them. It’s easy to assume that there must be a good reason for this and to not worry too much about whether or not there is any actual science behind it.

I’m as guilty as anyone else of believing what I read without always fact checking but I don’t want to be. I am a scientist, I have access to academic journals and the proper training to understand what is written in them. I can assess the quality of the research. I have no good excuse to just believe what I’m told, except perhaps that I’m kind of busy.

I also think it’s kind of important too. We’re talking here about things you wash your hair with, things you deliberately put on your skin, there’s value in understanding whether or not that might be harmful. On the one hand, if it is harmful, you can avoid using it. On the other hand, if it isn’t, you don’t need to expend time, energy or money avoiding it. Knowledge is power.

So, this time I looked into sulphates*. Want to know what I found out?

sulphate free
If it foams and makes soapy bubbles it almost certainly contains sulphates.

Sulphates are a kind of salt, a little like table salt but you wouldn’t want to eat them. There’s a huge range of varieties and they’re used in all kinds of industries. So at one end of the range you have things like calcium sulphate which is used to make plaster and lead sulphate which is used in certain kinds of batteries, and at the other end you have magnesium sulphate (also known as Epsom salts) which are used in therapeutic baths and iron sulphates which many people take as a mineral supplement.

However, mostly when you hear that you should try to use sulphate free products, we’re talking about sodium laureth sulphate (I’m going to call this SLS from now on and you’ll often see it labelled that way in ingredients lists too). It’s a detergent and is found in soaps, shampoos and some toothpastes, among other similar products. It also acts as a surfactant, which means it lowers the surface tension of water – that makes it better at cleaning stuff because the water can get into smaller spaces to help to remove dirt. The effect? It makes things soapy and foamy, so little wonder it’s in a wide range of products.

There are two reasons why you might be told to avoid products with sulphates:

  1. SLS is an irritant. This seems to be true
  2. SLS is carcinogenic. At the moment there does not seem to be any evidence that this is true.

Whether or not it irritates your skin will depend on your skin type and how much of it is in the products you’re using, as well as how much you use. You’ll already know yourself if a product irritates your skin and if that’s happening then obviously you shouldn’t use it but I’m guessing you don’t need me to tell you that.

The carcinogenic thing is worth discussing for a moment, though. It’s often really hard to pin down whether or not a substance is carcinogenic. At some point, a rumour spread that SLS was carcinogenic and once this kind of rumour starts it’s hard to stop it, especially if companies jump on the waggon to try to sell more products by marketing them as SLS-free. However, so far there is no evidence that SLS causes cancer. That’s not the same as saying that it definitely doesn’t but for the moment it’s reasonable to assume it’s fine. If you smoke, drink or eat flame-grilled food then these behaviours are far more dangerous to you in their capacity to cause cancer than using products with SLS in them is. SLS seems to be safe.

Skin irritation is no laughing matter though, as you’ll know if you have sensitive skin or if you’ve ever suffered from dermatitis. So it’s perfectly reasonable to try to avoid SLS in that instance. Also watch out for dandruff, skin that feels tight, sore eyes or mouth ulcers – any of these could be caused by sensitivity to something in a product your using and SLS could well be the culprit. There may be other reasons too; because it’s soapy it tends to strip away natural oils which can leave your hair and skin dry and sore (this is pretty much why it’s an irritant). If your hair or skin are naturally dry then you probably want to avoid this.

Another concern is the potential environmental impacts. SLS can get into the groundwater and in certain quantities it is toxic to fish and other aquatic animals. I found claims online that the manufacturing process creates pollutants as well but I couldn’t find more information to back that up. If anyone can point me to some I’d appreciate it.

So there you have it. If you have dry hair or skin avoid products which contain sulphates. If you have sensitive skin you should probably avoid them. As always if you find any product irritates your skin, dries it out or makes it sore then you should stop using it. Don’t worry, alternative products do work, they just don’t tend to foam up as much.

If none of that applies to you and you’re not too worried about it getting into the groundwater (and that’s not unreasonable, there are much bigger industrial scale processes which pollute the groundwater way more than you washing your hair) then don’t worry about it. Do keep an eye on things though, because your skin and hair do change a bit over time and something that doesn’t irritate your skin at one point in your life might irritate it at another. Use common sense and you won’t go far wrong.

*Throughout this I’ve used “sulphate” because I’m British. Sometimes you’ll see “sulfate” instead, especially in American English. That looks really weird to me, though.

I was asked if this was especially true for black hair. Since there is a tendency towards black hair being dry this would seem to be the case, however, I didn’t find any specific studies saying so. Anyone with dry hair, or hair prone to breakage, should probably avoid any products which make the hair drier.

8 thoughts on “Sulphate free

  1. You might find this link interesting:, wherein sodium lauryl sulfate (bad) and sodium laureth sulfate (not bad) are both addressed. Paula Begoun started out as a consumer advocate, educating folks about ingredients in skincare and makeup formulas. She now has her own skincare company. I like checking out the story behind ingredients at her site, and especially the Beautypedia reviews.

    Liked by 1 person

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