This article originally appeared on Time.com.
The Internet is rife with conspiracy theories about lip balm. Some claim it’s addictive, while others argue popular products are loaded with ingredients that actually promote chapped lips—therefore ensuring you buy more balm.
Experts say many of those rumors—many, but not all—are either exaggerated or silly. But to understand lip balm’s pros and cons, it helps to recognize your lips’ unique characteristics.
As far as skin goes, your lips are oddballs. Unlike your arms, legs and torso, your lips are covered in “transitional skin” that lacks a stratum corneum: a tough outer layer, explains Dr. Zoe Draelos, a North Carolina-based dermatologist and researcher. “This is why your lips look red compared to the rest of your face,” she says.
Draelos says lip skin is similar to the inner lining of your mouth and nose. But unlike those places, your lips don’t hang out in a warm, moist, protected environment. So when the weather turns cold and dry, your lips has a hard time coping.