The Tanning Process
How the Tanning Process works:
Tanning takes place in the skin's outermost layer, the epidermis. About five percent of the cells in your epidermis are special cells called melanocytes. When these cells are exposed to ultraviolet B light (the "burning" rays), the melanocytes "swell up" and secrete melanin - the pigment which is ultimately responsible for your tan. The pinkish melanin travels up trough the germinative layer and is absorbed by other skin cells. When exposed to ultraviolet A light (the "tanning" rays), the melanin oxidizes (rusts) and becomes darker. This darkening is your skin's way of protecting itself against too much UV light. This is called tanning, and the cells continue being pushed upward, toward the horny layer (top layer of skin) of the epidermis.
Heredity dictates how much melanin your body's melanocytes naturally will produce, since everyone has basically the same number of melanocytes. For example, the skin of African Americans contains enough melanin to create a black or brown skin color, while the skin of Caucasians will secrete much less melanin and is pale.
Avoiding overexposure is extremely important. Your tan should be acquired gradually, according to the guidelines prescribed by your salon professional. A sunburn occurs when too much ultraviolet light reaches the skin and disrupts the tiny blood vessels near the skin's surface. Remember, moderate UV exposure is the key to enjoying the positive benefits of the sun while avoiding overexposure!
Why does a tan fade?
Cells in the epidermis' germinative layer (also called the living epidermis) are constantly reproducing and pushing older cells upward toward the horny layer (dead epidermis), where they are sloughed off in about one month. As your skin replaces its cells, the cells laden with melanin fall off. In order to maintain your tanned look, your cells must be continually exposed to UV light so melanin production can continue.