What All Those Ingredients in Your Shampoo Actually Do

Your Ultimate Guide to What All Those Ingredients on Your Shampoo Bottle Mean

Considering it’s something we use every single day (or every eight days, depending on how serious your dry shampoo habit is), it’s kind of crazy that we don’t really know what’s in the shampoo we’re pouring all over our hair. Sure, it smells good, and there’s a kind that works best for every hair texture and need, but what’s actually doing the work? We did a little investigating. Consider this your glossary to all the weird and impossible-to-pronounce words commonly found on the back of your shampoo bottle.

Sodium Lauryl Sulfate:

This molecule, which often goes by SLS, is a surfactant, a.k.a. a cleansing agent. Its most important use is to cleanse the hair and scalp—and, as a bonus, it produces that foamy lather that makes a good hair-washing seem so luxurious. However, this family of sulfates has also been the topic of controversy. “Though sulfate-based shampoos do effectively clean the hair, they can also strip the hair of essential oils as well as irritate the skin,” explains Ron Robinson, cosmetic chemist and founder of BeautyStat. Think of how a too-strong face cleanser can strip skin and thus irritate it—same thing happens with sulfates. They can be harsh enough to fade hair color, so go for a sulfate-free formula to keep your color fresh and vibrant.

Sodium Laureth Sulfate:

Nope, not a typo. While sodium laureth sulfate (SLES, for short) is in the sulfate family, it’s not the same thing as SLS. “SLES has molecular attachments that make it bigger than SLS,” explains cosmetic chemist Ni’Kita Wilson. Because of that, SLES tends to cause less scalp irritation than its smaller sibling.

Dimethicone:

This silicone-based polymer is also common in complexion products like primers, since it gives skin that velvety slip. It serves pretty much the same purpose in your shampoo. “Dimethicone both conditions the hair and makes it feel smoother even before you add conditioner,” explains Robinson.

Panthenol:

Probably one of the better-known—and more crucial—shampoo ingredients, panthenol is a form of vitamin B5. It’s basically the moisturizer of your hair care regimen, says Robinson, and is used to hydrate and condition hair.

Citric Acid:

“Citric acid is an inexpensive yet highly effective ingredient to adjust the pH of the shampoo,” says Wilson. A low pH matters for skin, but what’s the big deal with your hair? Actually, the conditioning agents in both shampoos and conditioners work better under acidic conditions—so, in a low-pH environment.

Parabens (Methylparaben, Ethylparaben, Butylparaben):

You’ve probably heard of parabens already, because, like sulfates, they’re a serious point of contention in beauty products. “Parabens are preservatives used to prevent bacteria from growing in the product,” says Wilson. And while that sounds like a good thing—because who wants moldy shampoo?—parabens aren’t exactly innocent. “Certain forms have been shown to have the estrogen-like effects,” explains Wilson. This is definitely an issue, since high estrogen levels have been linked to multiple forms of cancer. However, Wilson says that it’s still much weaker than the phyto-estrogen effect of soy—so if you’re comfortable ordering edamame, you’re probably fine using parabens.

Zinc Pyrithione:

The #1 dandruff destroyer, this additive is more about your scalp than hair. Since it slows the production of skin cells, explains Wilson, it also puts a stop to flakes (which are essentially clumps of those skin cells). A few hair care brands use it in their non-dandruff formulas just to ensure scalp health, but there’s really no need for it unless you actually have flakes.

Cocamidopropyl Betaine:

This molecule, derived from crowd-favorite coconut oil, is kind of like a gentler version of SLS and SLES. “It’s a mild cleansing agent with conditioning properties,” says Wilson. The benefit is that it cleanses and softens hair, but it can still cause slight irritation.

 
This article first appeared on Glamour