Skin is vital. Notably it determines our appearance but, it is also the largest and outermost organ of the human body, which continuously confronts the external environment. A normal adult's body is covered with approximately 21.5 square feet (2 square meters) of skin. With a thickness ranging from 0.5-3mm, there are many components and layers that form the skin, a constantly changing and complex system of protection.
Skin, as the primary defense system, has different safeguarding functions such as UV-protection, anti-oxidant, and antimicrobial mechanisms. Skin is also a highly complicated and dynamic organ, and is responsible for many vital bodily functions such as providing the sense of touch and regulation of body temperature. The most obvious function of the skin however, is to controls the transcutaneous movement of water and other electrolytes with the Skin Barrier (also called epidermal permeability barrier).