A Very Dry Discussion of Sulfates

When we talk about sulfates in shampoos, conditioners, body washes, toothpaste (yes, really – it’s part of what screws with your taste buds for a while after brushing), etc. we’re usually talking about one of two different compounds: sodium lauryl sulfate (SLS) and sodium lauryl ether sulfate (aka sodium laureth sulfate or SLES). The former is cheaper to produce, but the latter is a bit less harsh.

I thought I’d start with this Big Bad, because it’s so ubiquitous these days. Crunchy, natural sites across the internet make it out to be evil incarnate, born of the unholy union of conspiratorial mega-corporations and super villain scientists. Is any of the fear mongering warranted? Can we stop screaming ‘corrosive’ for like five seconds and do some research? I’m not sure that word means what you think it means. If we’re going to get that flexible with definitions, please stop corroding my brain cells.

Sorry. I can only read so many all-caps rants before I start biting back, regardless of the topic. The internet: turning us all into toddlers with keyboards since 1997. Let’s back up a bit. What the heck are these compounds in the first place? And why include them despite the controversy? Working backwards through the name, the sulfates used are typically petroleum derived. They’re turned into sulfur gas, which is in turn treated with lauryl alcohol. Lauryl alcohol is derived from coconut or palm oil, making it sort of a synthesized waxy ester. Remember those? I wonder what jojoba oil would do to the process? Any chemists out know if it could work in this arena? Is it already being used? I am suddenly curious.

Anyway, tangent! So you put together those two wonder-goodies to produce hydrogen laurel sulfate, which is then neutralized with some sodium carbonate or sodium hydroxide, otherwise known as soda ash or washing soda. This stuff:


Pictured in a suspicious baggie

It just so happens I have some washing soda around, because it’s used as a fixative in dyeing clothes, and I’ve heard it could give a more pinky-purple tone to my cochineal dye. It’s harsh to work with, but so is bleach, and yet we keep that around. Always use gloves and proper ventilation, people.

When those three ingredients – sulfur gas, laurel esters, and sodium carbonate – come together, you get SLS, which is a detergent/surfactant. As compounds go, it’s kind of cool. Amphiphilic compounds like SLS act as a sort of chemical mafia on your behalf. When you lather up that soap or shampoo, it’s like letting these little mafiosos into a room and telling them you have a problem with Mr. Oily. He’s been clogging up business lately and causing facial chaos. So they surround him, leaving you physically unscathed while they whisk him away. The last you saw him, as you can tell the cops, he was alive and well. Just… you know, surrounded by angry guys with weapons. Meanwhile, Mr. Oily disappears into the East River, or whatever body of water your shower is draining into. And don’t worry about him bobbing to the surface anytime soon! Surfactants lower surface tension. It’s like those guys think of everything! Unfortunately for you, Mr. Oily’s family will show up looking for him and raising a whole host of uncomfortable questions within a day or two, but you can always bring back the SLS mafia to take care of them, too.

Artist's rendering of events

Artist’s rendering of events

Put a little less crazily, SLS molecules look a little like sperm or a balloon, with a hydrophilic head and a hydrophobic tail. When you introduce them to water, the head half tries to bond with it, while the tail tries bonding with the oil or with air or anything else present, sucking in and trapping whatever isn’t water. This creates balls of trapped oil, suspended in the water, which then get washed away.


The dark blue balls are hydrophilic heads; the green squiggles are the hydrophobic tails

So, on its face, SLS isn’t really that bad for you. If you use SLS too much, you’ll likely end up with dry skin and hair that’s dull and prone to breakage because you’ve robbed yourself of all your natural oils. But if you don’t use it at all, ever, the other products you do use, like dry shampoo, hair spray, and makeup, will build up and never quite get washed away. It’ll be as if Mr. Oily got comfortable and invited friends over to party. As with most things in life, the key lies in moderation. Also, try not to get yourself indebted to the mob. That’s always good advice.

SLS is not eco-friendly as long as petroleum is used in its production (it’s cheaper than working with naturally occurring sulfur, apparently). It is totally valid to object to the compound on environmental grounds. Provided alternate sulfur sources are used, and the coconut or palm oil is sustainably sourced, however, the finished product itself? Pretty much fine.

“But what about carcinogens?” you may be asking.

“1,4-Dioxane!” you may be screaming, fists in the air, tears in your eyes.

Calm down.

While trace amounts of 1,4-Dioxane can crop up in SLES, in particular, the FDA maintains that it exists in amounts too small to cause harm. Ethanolamine lauryl sulfates WERE carcinogenic, but those were pulled from the market by the 1970s and replaced with their two, now better known, cousins. It’s also worth noting that, and I’m quoting Snopes.com here, “three different agencies — the Occupational Safety and Health Administration (OSHA), the National Toxicology Program (NTP), and the International Agency for Research on Cancer (IARC) have all rated SLS as being non-carcinogenic.” It’s not like there’s some grand conspiracy where damning research is being suppressed. There’s info out there from so many different programs and agencies. As far as I’m concerned, it’s no worse than a lot of the other things I’m subjecting my body to regularly, like balsamic vinegar or sunshine, so whatevs.

When it comes down to it, yes, you likely use SLS and SLES containing products every day, but chances are you always use them in small amounts (they make up 15% or less of the total ingredient mix in shampoos) and in combination with water (which further dilutes your products). It’s important to factor in those elements. And, yes, SLS is used in industrial cleaning agents as well. It’s good for cleaning! That’s what makes it great for you and your floor! The big difference is, those industrial cleaners are going to be far more concentrated, because they’re meant for scrubbing linoleum, not skin.

IMG_20150309_191220804If you’re looking to replace or supplement your shampoo and conditioner with a sulfate-free and affordable alternative, I’m a big fan of the OGX line of products. I found a double-size bottle of their Awapuhi Ginger conditioner at CVS some time ago for half-price ($5), and have been riding that train for at least half a year now. Loreal has apparently launched a sulfate-free line as well, but I haven’t tried anything from that line and thus can’t vouch for it yet. If you’re tried it, let me know what you thought.

I, personally, always try to use sulfate-free conditioners. That’s one area where I’m in the crunchy granola camp. It just doesn’t make sense to me to include something drying and oil-stealing when I’m trying to replace the oils and moisture I just took out. Why do companies put SLS in conditioners in the first place? Possibly just because we’ve been conditioned (puns! Ha!) to expect a rich lather in our hair products, which is produced by adding in detergent, and SLS is one of the cheapest detergent options. Forgoing SLS means you might need to forgo the suds. Sorry, but that’s life.