The quest for eternal youth may be as old as human life itself, but the latest elixir to promise longer life—a molecule found in red wine—continues to surprise skeptics who can’t believe it could actually work. In the past five years, that compound, resveratrol, has been shown to slow aging in worms, flies, and mice. Other man-made compounds that work through the same mechanism, affecting a group of proteins called sirtuins, show similar promise.