You come into contact with sulfates every day. From shampoos to toothpastes, sulfates give products the ability to develop a satisfying lather. But, for such a common ingredient, “sulfate-free” seems to be a selling point for many shampoos. It’s tricky to understand if we should be avoiding them in our hair care. So what, actually, are sulfates — and are they bad for your hair?
I’ll be scientific for a moment: Sulfates are a group of salts that are produced either naturally or synthetically. The sulfates that are often found in shampoo and beauty products are sodium lauryl sulfate (SLS) and sodium lauryl ether sulfate (SLES). You may see sulfates lumped in with parabens, but they’re entirely different: Parabens are preservatives that extend the shelf life of products, whereas sulfates are actually involved in the cleaning process.
Sulfates are sort of like chemical detergents.
Both sodium lauryl sulfate and sodium lauryl ether sulfate essentially act like detergents, and are known as surfactants — which are chemicals that release the tension between liquids and solids, causing them to separate. In shampoos, sulfates create tension between the product washing your hair and the dirt you’re trying to clean: They latch on to both the water and dirt, dragging out oil and impurities from your hair. This process creates the foamy lather that many consider the hallmark of a good shampoo. In all my reporting, I could find no short cut to figuring out which shampoos do and don’t contain sulfates. For example, many popular shampoos contain SLS. Shampoos that contain a mixture of SLS and SLES, or just SLES, are rarer.
Sulfates have gained a reputation as a potentially irritating ingredient. Studies have noted that they can irritate eyes, irritate scalps, and strip more moisture than necessary from your hair, leaving it brittle (and more fragile). In my reporting, I’ve also heard of extreme cases where sulfates have caused acne along the hairline, and seriously dulled color-treated hair. Shirley Hagel, a color specialist at Spoke and Weal salon, puts it bluntly: “Sodium lauryl sulfate, which is the harshest of the sulfates, is the same ingredient used in Dawn dish soap.” Not all hair experts are as wary of sulfates, though. Masami Hosono, founder and creative director of the gender-neutral East Village hair salon Vacancy Project, was emphatic that sulfates are a worthwhile ingredient. Hosono says they are highly effective at cleaning your hair and scalp — especially if you have oily hair or product buildup. And sodium lauryl ether sulfate is known to be gentler and less irritating to skin and hair than sodium lauryl sulfate.
Are sulfates bad for my hair?
Fundamentally, the decision to use a sulfate-free shampoo comes down to your hair and skin type. Everyone has different hair and skin that will respond in its own way to any ingredient — including sulfates. Equally, if you have drier, frizzier hair, sulfate-loaded products can strip the little moisture from those hair types. They can also fade color faster, which is why popular color-safe products like Olaplex are sulfate-free. However, sulfates are highly effective at stripping oil and dirt from hair, so those with greasy hair may benefit from the detergent-like qualities of sulfates. After all, while they do have an ingredient in common with dish soaps, the two products are formulated entirely differently.
No matter what you decide to do, you can read our guides to the best shampoos, the best color-safe shampoos, the best shampoos for fine hair, the best shampoos for dry hair, and the best shampoos for oily hair to find one to best suit your hair and skin type. And if you’re concerned about losing the lovely lather of your shampoo, there’s no need to worry — we found plenty of pleasantly foamy options that are entirely sulfate-free in our guide.
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