It may come to no surprise to you that if you stop washing your hair, your hair will get dirty. Really dirty. If you don’t shampoo you hair with any kind of regularity, Eric Spengler, resident hair scientist at Living Proof, a company that formulates dry shampoo, even admitted that dry shampoo wouldn’t be able to cut it at that point. In an interview with Marie Claire, he also said, “If cleansing frequency is not often enough, the dirt and debris could lead to discomfort.” But dirt isn’t the only thing you’re going to be contending with when you toss out your shampoo. You might just start noticing the signs of pollution — on your own head.
“The skin and hair are the first things exposed to pollution, but skin often has the advantage of being protected by lotions, creams, or other treatments,” Susanna Romano, partner and stylist at Salon AKS in New York City told Shape. Your hair, on the other hand, doesn’t have that superpower. Dust, soot, smoke, and even “gaseous pollutants” (like car exhaust fumes) can make a home in your hair and onto your scalp, making for an itchy, irritated head. If you live in a major city, this problem will likely be even greater for you.