We’re experiencing the “skinification” of the scalp, says Desmond Tobin, professor of dermatological science at University College Dublin. A wave of products have launched – from scalp scrubs and acid exfoliants to deep-cleaning shampoos – claiming to “detox” the scalp and promising everything from shinier hair to boosted growth. This is especially possible in hard water areas where minerals in the water can react with products to form a sticky residue. Tobin says you may not need to buy an expensive product to deep clean your scalp. He advises people in hard water areas to use “a sulfate-free high-lather shampoo or to double-shampoo to break down mineral and product buildup”