Surprise: Sulfates Aren't Necessarily Bad for Your Hair—Here's How to Know When to Avoid Them

Achieving beautiful, healthy hair isn't just about sticking to a routine. Yes, it's necessary to do so, but it's also about paying attention to the ingredients in your hair care formulas. Some ingredients are more well-known, like formaldehyde, which studies show does have negative impacts. However, others are a little more ambiguous.

For example, sulfates. When we hear about a sulfate-free hair care formula, we can't help but blindly feel like it must be a better option for our hair. However, the truth is, many of us don't actually have any idea of the function of sulfates. And the truth is, sulfates aren't harmful to your hair, depending on your hair type and texture. Ahead, we're clearing up any confusion about sulfates in your hair care, including what it is and who should avoid it.

What are sulfates?

"Sulfates are a class of cosmetic and household ingredients used for cleaning," says Ron Robinson, a cosmetic chemist and founder of Beauty Stat. Typically, sulfates appear on the labels as sodium lauryl sulfate, ammonium lauryl sulfate, and sodium saureth sulfate.

In haircare, sulfates serve as the cleansing agent that makes shampoos sud up and cleanses the hair of dirt, oil, and debris.

Why are sulfates considered "bad" for the hair?

If sulfates are responsible for cleansing the hair, why are they considered bad for you? According to Gretchen Friese, certified trichologist at Bosley MD, sulfates can strip the hair of essential moisture. "Sulfates may strip away too much moisture and leave the hair dry and possibly damage it," she says. "They may also make the scalp dry and irritated."

For those with color-treated hair, sulfates can also strip and dull your hair color, says Jennifer Korab, a professional hairstylist. Not to mention, for those who get treatments, like a Brazilian blowout, sulfates can strip the smoothing benefits of keratin treatments.

Despite the potential risks of sulfates, it doesn't mean that everyone should automatically switch to a sulfate-free shampoo. "Sulfates get a bad rap by those that are spreading misinformation and fear-mongering," says Robinson. "Because this ingredient might not be good for some does not necessarily mean it is not good for others." And that brings us to our next question.

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Which hair types should avoid sulfates in their hair care?

"The key to understanding sulfates is to know your hair type, as well as acknowledging what treatments or services are currently present on your hair," says Michelle Cleveland, a professional hairstylist and owner of Hair Addict Salon. "If you have super dehydrated or coarse and curly hair, you may want to opt out of choosing products that contain sulfates." Those with a dry or sensitive scalp might also prefer a sulfate-free formula because it's more gentle. Additionally, if you've recently had a chemical or color service, a sulfate-free shampoo may help prolong the life of your service.

That said, if you're someone who likes the lightweight feel of their hair after using a traditional shampoo, or someone who needs a deep clean to get rid of buildup, you may prefer a shampoo with sulfates. Friese says people with fine hair textures are generally OK to use shampoos with sulfates, keeping in mind the other risks.

At the end of the day, like all things in beauty, it's all about evaluating your hair type and concerns. If you have very dry or over-processed hair or a sensitive scalp, then consider switching to a sulfate-free formula.

Just remember that sulfate-free formulas work differently than traditional shampoos. "Sulfate-free shampoos are most definitely still cleaning your hair and scalp, but you won't see the usual sudsy lather that you've come to expect from your normal shampoo," says Cleveland. Sometimes, people will overuse or waste the product in hopes of seeing their hair sudsy, but sulfate-free formulas don't give that experience because it offers a more gentle cleanse.

One of the best sulfate-free shampoos for damaged hair to try is the Amika The Kure Bond Repair Shampoo for Damaged Hair ($18, sephora.com). If you have curly hair and want to try a sulfate-free formula, we recommend the Pattern Beauty Hydration Shampoo ($20, ulta.com), which is suitable for all natural hair types.