Chapped Lips

When it comes to battling the elements, your skin serves as your front line of defense. But it's your lips that really bear the brunt of the attack from sun, wind, cold, and dry air. It's a wonder our mouths don't suffer more in the line of duty-we bundle up in extra layers during the winter months, leaving our lips exposed.

"Lips are mucous membranes, so they have very thin surface layers of skin," says Los Angeles dermatologist Jessica Wu, MD. When compared to the skin on the rest of your face, Wu says, lips are the most vulnerable to drying out. In fact, research shows you lose up to 10 times more moisture through your lips than you do elsewhere on the face or body.

Arid winter air, arctic blasts of wind, and the low humidity indoors all lead to a crisis for your lips in the form of dehydration. Once moisture is sapped from skin cells, they become fragile so your lips develop tiny splits and cracks. These tiny tears are what make chapped lips so painful -- heat, acidic food, even toothpaste can aggravate raw skin.