What Is It?
Normal skin has a soft, supple texture because of its water content. For skin to feel soft, pliable and "normal," its top layer must contain a minimum of 10% water — and ideally between 20% and 35%.
To help protect the outer layer of skin from losing water, the skin's sebaceous glands produce an oily substance called sebum. Sebum is a complex mixture of fatty acids, sugars, waxes and other natural chemicals that form a protective barrier against water evaporation.