Are Sulfates *Really* That Bad for Your Hair? Here's the Truth
Not gonna lie—I don't think I even knew what sulfates were until, like, after college. My go-to shampoo for the first half of my life was any generic formula that smelled good, or whatever drugstore shampoo I could find in bulk. I never once thought about sulfates, or asked myself if sulfates are bad for hair. But oh, how times have changed. Now, my bathtub is crowded with a zillion specific shampoos and conditioners, like a dandruff shampoo for when I'm feeling itchy, a volumizing shampoo for when I blow-dry my hair, a hydrating shampoo for when my hair feels like straw...it's a whoooole process.
While the majority of the shampoos I use these days are free of sulfates, I'm not afraid to admit that I still wash my hair with a sulfate-based shampoo from time to time. I won't say that you definitely should use one, too, but I will provide you with the expert-backed information you need to make that decision for yourself, so keep reading.
Meet the experts
Nick Dindio is a cosmetic chemist and the director of research and development for SOS Beauty. Dindio has worked with brands such as Glossier, Oribe, Tata Harper, and ColourPop.
Meri-Kate O'Connor is a Los Angeles-based hairstylist at Cooper Hair Salon in West Hollywood. O'Connor is a colorist, stylist, and extension expert.
Mona Gohara, MD, is an associate clinical professor of dermatology at Yale School of Medicine, and a board-certified dermatologist at the Dermatology Physicians of Connecticut in multiple locations in CT. Dr. Gohara has previously spoken to Cosmo on the topic of acne face wash.
Monaé Everett is a celebrity hairstylist, author, and public speaker with over 20 years of experience specializing in natural hair based in Brooklyn, NY. Everett has previously spoken to Cosmo on the topic of sulfate-free shampoos.
Why do some shampoos have sulfates?
Cosmetic chemist Nick Dindio clarifies that when we're talking about sulfates in this context, we're referring to sulfated detergents, with the most common being sodium lauryl sulfate (SLS), sodium laureth sulfate (SLES), sodium coco-sulfate, ammonium lauryl sulfate, and ammonium laureth sulfate. “These ingredients are all surfactants and are very good at their job,” Dindio explains, adding that surfactants have a portion that is water-soluble (sulfate), and a portion that is oil-soluble (lauryl, laureth, or coco), so "they can surround particles of oil and dirt to wash them away down the drain.”
The reason for them being in your shampoo is that they are impressively good at stripping away all the dirt, grime, and product build-up from the hair—but oftentimes they're too good. To give you an idea of just how rough sulfates can be, board-certified dermatologist Mona Gohara, MD, previously told Cosmo that you can even find the same surfactants in your dish soap. And therein lies the potential problem for your hair, my friends.
Are sulfate-free shampoos really better?
Sulfate-free shampoos are better for some hair types, yes, but that doesn't automatically mean sulfate-filled shampoos are bad. According to Dindio, all detergents work in the same manner; they just have different properties, like foam quality, foam volume, and cleansing power. “Sulfates are not inherently bad, but they can be aggressive—as could all detergents—if used at too high of a level,” Dindio explains.
While SLS, SLES, ammonium lauryl sulfate, and ammonium laureth sulfate are some of the most common sulfates to look out for, it's not quite as simple when looking for sulfate-free detergents, since there are so many. Personally, I like to refer to a surfactants list to see which surfactants are harsh, mild, or gentle before buying a shampoo.
If the first few ingredients are on the harsh (i.e., sulfates) list? I would suggest skipping it if you have curly, damaged, or dry hair, and instead opt for sulfate-free formulas. But, as hairstylist Monaé Everett previously told Cosmo, if you have oily or fine hair, sulfates or harsher detergents might be okay for you. If sulfates seem to be way too stripping for your hair, then yeah, that's probably not the best shampoo for you and a sulfate-free option could be better.
Do sulfates strip hair color?
“Sulfates can oftentimes remove color pigments and chemical treatments—such as keratin treatments—faster than you would like, so I definitely recommend not using them at all, or as little as possible, to help prolong your hair,” hair colorist Meri-Kate O'Connor says. Dindio, however, argues that it's more about the concentration 0f the detergent, rather than the detergent itself, but it's also not a bad idea to opt for a sulfate-free formula for color-treated hair to be safe.
Is sulfate-free shampoo good for fine hair?
Here's the thing about sulfate-free shampoos: They're all incredibly different. I've used sulfate-free shampoos that are basically co-washes—waaaay too heavy and moisturizing for my fine hair. But I've also used sulfate-free shampoos that are surprisingly sudsy and strong, to the point where I've had to re-check the bottle to make sure it really was sulfate-free (again, this is why I always cross-check the first few ingredients of a shampoo with a detergents list before buying).
Do you really need a clarifying shampoo?
If your hair is extra dirty, has lots of product buildup from silicones, or you're trying the Curly Girl Method, then yes, you should have a clarifying shampoo on hand that specifically contains sulfates. Hairstylist Meri Kate O'Connor says someone who is oil-prone or is exposed to a lot of dirt or dust could benefit from sulfates because of how deeply they can cleanse the hair. But unless you're covered in dirt every single day, you definitely don't need to use a clarifying shampoo all that often, only on occasion.
I, personally, love using sulfates occasionally for stripping away all the grease and oil that weighs down my fine roots, as does Cosmo's deputy beauty director Chloe Metzger, who has thin, fine, curly hair that's prone to build-up. That said, if your hair is fine and brittle, O'Connor doesn't recommend using sulfates, because they can dry the hair out even further. And it's not just about the hair; O'Connor also says that anyone with scalp concerns, like dermatitis or eczema, should avoid sulfates as well since they can irritate the skin more.
Do all clarifying shampoos have sulfates?
Good question! A lot of 'em do, but not all clarifying shampoos have sulfates. Sulfates tend to give the strongest cleanse, which is great for deep-cleaning oil and dirt from your hair, but there are plenty of sulfate-free versions as well. “Sulfate-free shampoos have come a long way since their inception, and there are many great options out there,” Dindio says. We've rounded up some of our faves for you below.
The final word:
To sum it up, sulfates might be better at cleansing, but sulfate-free formulas might be better for your needs. My hair is flat and stick-straight, I don't color it, it gets greasy fast, and I load up on the dry shampoo and volumizing products. The best way for me to reset my hair is with a sulfate-filled formula.
If your hair is dry, brittle, damaged, or color-treated or your scalp feels a little compromised, you'll probably want a milder formula. As Dindio explains, it's more about the concentration of the sulfates than the actual sulfates themselves, but with so many options out there (see above), you definitely don't have to use 'em if you don't want to.
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