The skin on the lips is unlike any other. The outer layer (the stratum corneum) is extremely thin or completely absent in most people. It has fewer and different glands from ordinary skin and almost no melanin, the natural pigment in the skin that helps screen out the sun’s harmful rays.

Lips are also so prominent and exposed, that they receive the full brunt of environmental exposure – the sun, wind and cold. Even indoors, parching from central heating or air conditioning systems can cause dry lips.

Dry lips can also be caused by illness, as people tend to breathe through their mouth when they have a cold or the flu. Smoking, eating strongly flavoured or spicy food will damage the mucous membrane of your lips.