What's Up With Sulfates?

In Depth
What's Up With Sulfates?

If you read the internet (and if you are reading this, you do) you probably know that there are a lot of “chemicals” in everyday household items and, even if you don’t believe it, you’ve probably read that these chemicals are going to punch you in the face, take away your happiness and maybe force you to finally read Infinite Jest, or other manifold and unspeakable horrors.

Some of the culprits accused of threatening you with their chemistry are sulfates. Just Google “sulfates” and the second result is about whether or not they are safe. So is the third. Sulfate is an overarching name for mineral salts that contain sulfur. There are many kinds of sulfates, but the ones you bump into the most often are sodium lauryl sulfate (SLS) and sodium laureth sulfate (SLES).

To understand why they are there, you need to understand a little bit about how soap works. I did not understand how soap works, so I spoke with a chemist, who basically just gave me a chemistry textbook. “General Chemistry” by Darrell Ebbing and Steven D. Gammon, to be exact (and to a lesser extent this UC Davis site) and he walked me through it. Chem 101, if you will. So here is the lesson I was given:

Oil and water don’t mix. You know that. Sulfates bridge that divide between oil and water, helping you clean all that gunk out. But wait, why do you even want to clean out the oil? Because after all, aren’t your natural oils supposed to be good for you? Well, oil is where bacteria resides. Bacteria like to eat the oils on your skin (sebum). So as they eat, they produce the rancid byproducts of bacteria that join with your sebum and make you smell bad. So, contained in all of your natural oils are bacteria and their stench.

Soap helps remove infested oil and the bacteria themselves, which stick to your skin. You can’t get clean with just water because the oil repels water. Enter sulfates. They bridge that gap between oil and water, break the bonds of bacteria and set you free and clean.

So, do they strip you of oils? Yes. They do. They have to if you are going to get clean. But here is the thing: your body is always producing oils. Take some away and your body produces more. But there is also an important caveat here. Sulfates only take away oil from your skin. Your hair is dead. It does not make oil. It makes nothing. So, stop saying that your hair was stripped of oils. That was your skin and it’s already made new oils.

And another caveat: All soap takes away oil and cells. It has to. That is how soap works. So, even if at the end of this article, you give me the middle finger and go buy some sulfate-free soap, you are still losing oils. That’s science.

Which brings me to the next part: do sulfates strip more oil from your skin than necessary? There is a lot of anecdotal evidence out there that suggests soap with sulfates is caustic for people with sensitive skin. But studies show sulfates are a major skin irritant when used in high concentrations, like in cleaning solutions, not your shampoo. Your normal shampoo isn’t highly concentrated. In fact, the biggest danger from sulfates is if you drink a high concentrations of sulfates, you can get diarrhea and a stomach ache. But I’m going to go out on a limb and say no shampoo, even all natural, is good to drink.

Here is the rub: if a soap doesn’t have sulfates, it uses a carboxylate which after a lot of science is actually less soluble than a sulfate. And what that means is sulfates are actually able to give you a less caustic soap than a carboxylate soap. Also, carboxylate soap leaves more soap scum behind because it is more likely to bond with the magnesium and calcium in your water than get rinsed away by it. There are some ways to mitigate this soap scum problem, but these types of soaps do leave behind more residue than a sulfate soap.

So what about all those accusations of sulfates stripping cells away? Well, yes. But you strip cells off your body all the time. Right now, even at this moment, you are sloughing cells everywhere. You are gross and evil. Not really, of course. (Unless you are gross and evil, but then it has little to do with your cell stripping.) Losing cells? That’s natural.

I also came across accusations that sulfates are the same stuff used in detergents and other harsh cleaners. And well, yes. Anything is harsh in high concentration. Even “natural” things like cinnamon oil, which is marketed as a natural hair cleaner can be corrosive to metal if it is concentrated enough. Even “natural” things like cinnamon oil, which is marketed as a natural hair cleaner can be corrosive to metal if it is concentrated enough. People have died from drinking too much water.

Finally, the biggest alleged crime of sulfates is that they can contain 1,4-dioxane, which is a carcinogen. This is true. A 2001 study did find trace amounts of 1,4-dioxane in personal care products. But if you look at the evidence closely, you see that only very small amounts of 1,4-dioxane have been found in personal care products. And what does that even mean? Because according to an EPA report, the data isn’t conclusive on whether 1,4-dioxane exposure has ever lead to cancer deaths in humans. So calling it a “known carcinogen” is a little spurious. Only very small, tiny amounts appear in personal care products and the FDA says that these levels are safe for humans. So, if you don’t believe the FDA, that’s okay. But just know that going to a car wash will probably expose you to more chemicals than that bottle of shampoo.

There have been studies that have shown some link to cancer in animals and 1,4dioxane. But there is no way any normal daily use of shampoo or soap is going to expose you to the amounts that were exposed to the animals in those studies.

Ultimately, the truth here is that sulfates do not cause cancer.

Look, everything is made up of chemicals. Even the natural Dr. Bronner’s soap uses peppermint oil that contains over 70 different chemical compounds. If you don’t understand how they work, it’s easy to get mislead about their dangers.

Bottom line: I need to go suds up my hair.

Illustration by Tara Jacoby.

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