Skin Structure
The skin is made up of four layers; the horny outer layer, which consists of dead cells; the epidermis; the dermis; and the subcutaneous layer of fat. The skin is designed to be waterproof, and nothing that is put on the skin, such as moisturizers, cellular renewal creams or anti-ageing creams, can penetrate any deeper than the outermost layers of the epidermis.
Skin grows from within outwards. This occurs at the basal cell layer, which separates the dermis from the epidermis. These cells are continuously reproducing and moving forward towards the skin's surface. When these cells die, they form the horny layer that acts as a safety barrier and protects the fresh cells underneath. At the surface these cells form keratin, a layer of tough material that is thickest in body areas subject to the most wear and tear, such as the palms of the hands and soles of the feet. The surface layer is in a constant state of renewal as the dead cells are sloughed off and replaced by other cells. Exfoliation removes this surface layer, leaving the skin smooth.
Collagen, the elastic tissue in the dermis layer, give the skin its suppleness, smoothness, and plumpness. As you age, the collagen tissues break down, which causes skin to sag, wrinkle, and thin. Nothing short of cosmetic surgery can prevent these signs of ageing. The rate at which your skin ages is inherited, so if your parents have young-looking skin, chances are you will too.