Computers and Electronics What is the number 1 selling shampoo? What is the number 1 selling shampoo? YES! HEAD & SHOULDERS SHAMPOO, commonly recognized as a dandruff scalp treatment shampoo, it is the most popular brand on the market and for good reason. Related Posts:Is Nizoral anti-dandruff shampoo safe for color-treated hair?Why is Dove shampoo bad?How do you use anti dandruff shampoo and conditioner?What kills dandruff on scalp?