Drink eight glasses of water a day: We’ve heard that advice so long that we’ve just come to accept it. But a recent review of 27 studies from the University of Pennsylvania found no
proof that chugging lots of water improves skin tone, relieves migraines or helps flush out toxins. “In fact, there’s evidence your body is less efficient at filtering out toxins when your water intake is higher,” says review coauthor and professor of medicine Stanley Goldfarb, M.D. So how much water do you need? Trust your thirst, says Dr. Goldfarb.