When it comes to exfoliants, you no longer have to choose between brighter skin and a happy skin barrier. The best PHA products deliver both, gently whisking away dead skin cells while helping skin stay comfortable. "PHAs, or polyhydroxy acids, are a type of chemical exfoliant—and what makes them special is that they slough off surface buildup much more gently than other acids," says Mamina Turegano, MD, a board-certified dermatologist based in New Orleans.