Why are our lips darker than our skin?

The fact that human lips contain less melanin than the rest of the skin combined with the fact that they are composed of fewer skin layers results in their pink color. The exact color depends on the color of underlying tissue and the degree of blood flow, according to HealthHype.com.

Genetics, which control melanin levels and skin thickness, are another determining factor in the color of a person's lips, reports HealthHype.com. While they are similar to skin in many ways, lips serve as the meeting place of the mucous membrane of the inside of the mouth and the outer facial skin.