Researchers from Case Western Reserve University in Ohio used the annual Twins Day Festival in Twinsburg, Ohio, to identify 79 pairs of twins in which one sibling smoked and the other didn't.
The twins who were smokers showed many more signs of skin aging, the researchers found. Their faces featured more wrinkles, creases, droops and jowls.
"Smoking harms virtually every organ in the body, including your skin," said Danny McGoldrick, vice president for research at the Campaign for Tobacco-Free Kids. "Whether you are doing it for vanity or your health, one of the most important health decisions of your life is not to start smoking, or to quit if you have."