It's called the Dermal-Epidermal Junction (or DEJ) a narrow wall of rolling, "wave-like" cells just below the surface of the skin. No more than 100 nanometers thick. A complex layer of cells acting as the interface between the epidermis and the dermis, playing a critical role in tissue repair and the soundness of the skin architecture. In simple terms, the DEJ control the structural integrity of your skin. It's the key to reducing the visible effects of deep wrinkles cause by photodamage and aging.

The epidermis is the outer layer and functions as a barrier to the external environment. The cells of the epidermis, keratinocytes, move from the bottom layer of the epidermis to the top layer building up a large amount of keratin and developing a tough outer shell. Once these cells reach the top layer, they flake off. If this process becomes abnormal the skin can look scaly.