From the day you bought your first tub of Noxzema, you’ve been told that your skin is oily or dry or combination orĀ sensitiveĀ or, most curious of all, normal. “It constantly frustrates me,” says Mona Gohara, an associate clinical professor of dermatology at Yale School of Medicine.

“People get thrown into these buckets, and it doesn’t make sense.” Then she adds, wryly, “It’s a soapbox I’m currently on.” And the message is this: We’ve taken for granted that these classifications define us and our epidermis, but almost nobody fits neatly into one.