Move over, face. The scalp is the new frontier of consumer obsession, and brands are absolutely thrilled about it. According to Desmond Tobin, professor of dermatological science at University College Dublin, we're witnessing the "skinification" of the scalp. After years of obsessing over facial skin, we've finally looked up and thought, "Wait, what about up there?"

Cue the wave of products: scalp scrubs, acid exfoliants, deep-cleaning shampoos - all claiming to "detox" the scalp and promising everything from shinier hair to boosted growth. Tobin, with the weary tone of someone who's seen this before, notes, "It's obviously a business opportunity. If brands have something that works on skin, they might be able to roll it over. It goes quickly and cheaply into another product range."

But here's the rub: Tobin says he'd never use the word "detox," because these products aren't removing anything toxic in the dangerous sense. An occasional scalp cleanse can be useful, though. Some people pile on so much product that it builds up on both hair and scalp, potentially clogging hair follicle openings and interfering with optimal hair growth. A quick morning shower might not cut it, especially in hard water areas where minerals react with products to form a sticky residue. And if you live in a highly polluted urban area, you might also have traffic-associated chemicals deposited on your scalp. Charming.

Before you shell out for an expensive potion, Tobin suggests a cheaper alternative: use a sulfate-free high-lather shampoo or double-shampoo to break down mineral and product buildup. Because sometimes the answer isn't a $40 scrub - it's just washing your hair twice.