How The pH Of Your Shampoo May Affect The Look Of Your Hair
Think of your favorite shampoo. If you are a beauty fan, or just care about the stuff you're putting on your hair and body, you likely already know a few things about it. Say, for example, you probably know whether it has sulfates or not. You might know whether it has silicones. And you probably know if has any added actives, like conditioning agents or antioxidants.
You probably don't know the pH.
Why pH matters with hair care products:
"The one thing I wish more people knew—my clients and professionals included—is pH and how it affects hair and scalp health," says Christine Thompson, colorist and co-founder of natural salon Spoke&Weal. "It takes some time to explain it properly, but once people know the why behind it, they never stray from the path."
As a little chemistry lesson, everything has a pH level that ranges from 0 to 14. When the pH is neutral, that means it's right in the middle at 7; it's acidic when it's below that, and when it's alkaline when it's above. Your scalp, like the rest of your skin, runs at about 5.5. This is all important because your skin's pH is and can be affected by the products you are putting on it. Here's what we know from research1: When a shampoo has a pH level that is at or below 5.5, it reduces frizz and friction between fibers, which means less damage overall. It also means the scalp stays at its natural pH. When a shampoo has a pH higher than that, it "may increase the negative electrical charge of the hair fiber surface and, therefore, increase friction between the fibers; this may lead to cuticle damage and fiber breakage," according to a study on the pH of hair products2.
So pH in hair care should be a real concern. In that same study, the researchers found that of mass brands, 66% of the shampoos had an alkaline pH. Professional or prestige brands scored better, with only 25% having an alkaline pH. (Dandruff shampoos scored the worst, with 81% having a higher pH.)
Signs your product's pH might be too high & what to do:
So how do you know if your shampoo's pH is affecting your hair? "You're going to notice your scalp is dry and irritated, and for your hair, you might notice more frizz," says hairstylist Levi Monarch.
If you suspect this is you, there are a few things you can do. The first step is to nix sulfates, if you haven't already. (Part of what makes sulfates so drying is the fact that they are anionic detergents, which strip hair's nutrients and leave an alkaline residue in its place.) Instead, look for shampoos with balancing, fatty-acid-derived surfactants, like sodium cocoyl isethionate and sodium methyl cocoyl taurate. "For a while we thought surfactants were bad for your hair and you were never supposed to use them, but these ones derived from coconuts work really well and won't fade color," says Thompson.
But even if you've done that, your pH can be altered naturally through your water or other environmental aggressors. "Water's pH can vary, but it's usually around a 7—so when you wash it, you are bringing your hair's pH up to a mid 6—that's the same pH as a demi-permanent color," says Thompson. "And that's every time you wash your hair." So one more thing you can try is an acidic hair rinse. These are products typically made with acidic apple cider vinegar, but you can also DIY your own apple cider vinegar hair rinse. "These are going to balance the pH level of the scalp and close the cuticle, so your hair is smoother and shinier," says Monarch. But never put just straight vinegar on your hair; you'll go too far toward the other end of the pH spectrum.
So until shampoos and other hair products start slapping their pH on their product labels (some brands in Europe already do it!), there's no way to tell how alkaline your wash is. But with these general guidelines, you'll be better equipped to figure it out on your own.
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Alexandra Engler is the beauty director at mindbodygreen and host of the beauty podcast Clean Beauty School. Previously, she's held beauty roles at Harper's Bazaar, Marie Claire, SELF, and Cosmopolitan; her byline has appeared in Esquire, Sports Illustrated, and Allure.com. In her current role, she covers all the latest trends in the clean and natural beauty space, as well as lifestyle topics, such as travel. She received her journalism degree from Marquette University, graduating first in the department. She lives in Brooklyn, New York.