Here’s what 6 experts have to say about sulfates in shampoo

Mar 05, 2024

Here’s what 6 experts have to say about sulfates in shampoo

Guess what? Sulfates in your shampoo might not be that bad

Everyone loves a good, solid lather when they wash their hair. But have you ever wondered where that lather comes from? 

Get ready to dive headfirst into the world of sulfates in shampoo—the foaming agents that make our haircare routines feel super luxurious. 

If you’ve heard of sulfates, but don’t know how they work, where they come from, and why they’re an ingredient in so many shampoos (and tons of other bathroom staples), we’ve got the answers for you. 

We’ve also rounded up advice and guidance from six hair experts to give you a complete picture of these sometimes-divisive ingredients. 

[Alt text: A woman lathers her hair thanks to the sulfates in her shampoo. Credit: Pexels]

Sulfates in shampoo: what are they?


Let's kick it off with a quick chemistry class (minus the boredom). Sulfates are the cleansing agents responsible for that satisfying lather when you shampoo, and when you use toothpaste, dish soap, laundry detergent… the list goes on. They're molecular magnets called surfactants, attracting both water and oil, and creating a foam that cleanses your hair thoroughly.

There are four kinds of surfactants you’ll usually find in your bathroom:

  • Sodium Lauryl Sulfate (SLS): This is the most effective at removing grease and grime, and it creates a lot of foam. It also has the smallest molecular structure in the group, which means it can penetrate deeper and remove more dirt.
  • Sodium Laureth Sulfate (SLES): This one is a much more gentle cleanser, and it has a larger molecular structure. 
  • Ammonium Lauryl Sulfate (ALS): Even more gentle than SLES, and with a more complex molecular structure that isn’t as easily absorbed by skin. That means it’s less likely to irritate your scalp.
  • Sodium Lauroyl Methyl Isethionate (SLMI): This one, which is sulfate-free and always derived from coconut oil, is one of the mildest surfactants you can get. 

While most surfactants can be made synthetically, they can also be derived from coconut oil. The ones you’ll usually find in your shampoo are SLS and SLES, paired up to create a super-cleansing duo. 

Apart from their cleansing power, sulfates are used in shampoo because they foam up and that leaves a feeling of softness on the skin. It’s also visually satisfying for people, and seeing that foam just generally makes things seem clean. Which, they likely are because sulfates have anti-microbial properties––removing oil from the scalp and the hair, and helping your shampoo rinse away like it was never there. 

Why do sulfates in shampoo get such a bad rap?

If you’ve ever had a debate about shampoo (who hasn’t), there’s no way sulfates weren’t a sticking point. 

The problem with sulfates is a two-parter. One, they’re synthetic, which is quickly becoming a four-letter word in the beauty world. And two, they might not be particularly healthy for your hair and scalp. 

Brands usually formulate their shampoos with sulfates because they’re effective and cheap. But, as Gretchen Friese, certified trichologist at Bosley MD, told Real Simple, sulfates can remove the moisture your hair needs. "Sulfates may strip away too much moisture and leave the hair dry and possibly damage it," she said. "They may also make the scalp dry and irritated."

Luckily, shampoo formulations are evolving, and the ones formulated with sulfates aren't as drying as they once were. "There's been a greater appreciation for scalp and hair health over the past 10 to 15 years," board-certified dermatologist Marisa Garshick, MD told InStyle. "Brands are essentially adding ingredients that have a positive impact on hair health. So even shampoos that have a sulfate-based surfactant are incorporating different types of conditioning agents or hydrating ingredients, combating that potential for dryness and irritation."

What’s a bit more alarming is the idea that sulfates can cause cancer. But according to Dr. Brendan Camp, a double board-certified dermatologist at MDCS Dermatology in New York City, this is a myth. He backed that up with a study from the US National Library of Medicine when speaking with Today.

"The most egregious claim by far is that SLS is carcinogenic [16,32]. The origin of this claim is uncertain, but it is likely to have derived from multiple misinterpretations of the scientific literature. There is no scientific evidence supporting that SLS is a carcinogen," the study reads.

London-based hairdresser Michael Van Clarke sees this debate for what it is: complicated. "The sulfates story has been blown up by an army of keyboard warriors who haven’t looked deeply into the science,” he said to Woman & Home. “As an effective detergent, sulfates can be both good and bad—depending on your hair and skin type.” 

[Alt text: A sudsy lather courtesy of the sulfates in shampoo. Credit: Pexels]

So… should I cut sulfates from my hair diet?

As Van Clarke said above, it all depends on you and your hair and skin type. Got greasy hair that you always apply tons of product to? Sulfates might be your BFF to scrub it all away. But, if your hair is processed and your scalp is sensitive, it might be time to break it off with sulfates.

People with finer hair might benefit from sulfates in shampoo –– without it, your hair can look flat and dull. But, use it sparingly, because the harshness can also be drying. 

Oma Agbai, an associate clinical professor of dermatology at the University of California, Davis School of Medicine, recommended milder sulfate alternatives to the National Geographic. She suggests surfactants like sodium lauroyl sarcosinate and sodium cocoyl glycinate. For people with curly hair and or color-treated hair, sulfate-free shampoos are the way to go, because sulfates can make color fade faster.

People with dry or frizzy hair might also want to consider going sulfate-free. You won’t lose as much of your hair’s natural oil, and your scalp will also stay more hydrated. If you have curly hair, keeping those curls hydrated is key to maintaining their bounciness and shape. If you have sensitive skin or struggle with eczema, sulfates might be worth avoiding, as well. 

All that said, if you’ve been using shampoos with sulfates for years and you’re happy with your hair and your scalp health, no need to fix what isn’t broken. If you’ve got an oily scalp and you need to remove product buildup, you’re going to get a better cleanse with those sudsy sulfates. 

Cosmetic chemist Perry Romanowski went to bat for sulfates, too, when he told Teen Vogue that the movement to keep sulfates out of products is essentially fear-mongering. “The beauty industry doesn't believe that sulfates are dangerous,” he said. “There are some marketers who are convinced that consumers believe the ingredients are dangerous, and they have used that fear to sell their own products. It's only recently, within the past 15 years, that large companies have advertised sulfate-free products."

How to find your shampoo sweet spot

Whether you choose to sulfate or not to sulfate, there are a few general rules we recommend you follow based on your hair type and haircare habits:

  1. Don’t wash your hair more than you need to. Every day washers, we’re looking at you. Oily hair definitely needs a thorough cleanse the most often, but if you can cut it to every other day, you win. Shampooing too frequently can strip moisture, drying out your hair and making it look dull. 
  2. Think about your hair type. Got fine, thin hair? Choose a lighter shampoo that’s formulated to boost volume. Got dry and curly hair? Go for creamier shampoos and conditioners (conditioner is a must, more on this in a sec). Luckily, most shampoos and haircare products are pretty clearly labeled these days, so it shouldn’t be too hard to figure out what’s right for you.
  3. Did we mention conditioner? Shampooing is great for removing excess oil, dirt and product buildup. But it is nothing without its other half: conditioner. No matter your hair type, conditioning is super important. Even if your hair is thin, trust us. If you’re worried about extra weight, only use that conditioner from the mid-lengths of your hair to the ends. But use it. Please.
  4. A few words on heat tools. We all love our hot tools. Dryers, curling irons and flat irons give hair a hit of shine and make styling so much easier. If you’re using hot tools every day, make sure they’re good ones, like TYME Beauty’s Tyme Iron Pro, and make sure you’re taking good care of your hair both before, during and after styling. A sulfate-free shampoo that’s less stripping might be a good idea, and a sulfate-free dry shampoo instead of conventional washing is an even better one.

[Alt text: A happy woman with curly hair who uses shampoo with sulfates. Credit: Pexels]

The final say on sulfates

As with all choices in life, this one’s personal. Hopefully, these expert insights have helped you better understand the impacts of your sulfates on your hair, and helped you feel empowered to take care of your hair as best you can. Whether you love that lather or you’re saying no to suds, you’ll at least have ammo next time someone questions your sulfate stance (this happens all the time, right?). Either way, we see great hair days in your future.