“I think people are a little overwhelmed,” acknowledges New York dermatologist Ellen Marmur, M.D., who created her light-emitting MMSphere 2.0—which offers four different colors of glow, each with its own alleged benefit—to help her patients maintain their in-office results between appointments. “There’s such a variety of devices coming to market now—you can wind up choosing blindly if you don’t understand the technology,” says Marmur