The Inkey List Alpha Hydroxy Acid Serum ($11) not only has 10-percent fruit acids for exfoliation, it also has a water-soluble form of vitamin C that breaks down into ascorbic acid when absorbed into skin. That means dead skin cells are eliminated from the surface, while skin gets brighter and smoother from within. (If you're not convinced, 95 percent of the Sephora shoppers who reviewed this would recommend it to others, too.)