How do you know if you have dandruff? You might be surprised to learn that one out of two people have experienced it. And contrary to popular belief, flakes aren’t the only sign. In fact, the most common sign of dandruff is itch. And there are other invisible signs, too, like scalp irritation and dryness. Fortunately, Head & Shoulders is clinically proven to be effective on all the signs of dandruff. To treat all the signs of dandruff and get great looking hair, I recommend Head & Shoulders shampoo.