"This idea that we now have these multi-step regimens with these ingredients in them and we are going to put them on 11-year-old skin, that isn't what those products were designed for," Cobb said.

At best, the products are usually a waste of money, Hooper said. (The average cost of skincare regime in the Northwestern study, for example, was $168, but one exceeded $600.) “When you are ...

These are the formulas dermatologists recommend for tackling lines and wrinkles, age and sun spots, and dryness.

"This idea that we now have these multi-step regimens with these ingredients in them and we are going to put them on 11-year-old skin--that isn't what those products were designed for," Cobb said.