To build an awesome tan, tan regularly. Allowing too much time between visits will cause your tan to fade. Most people will see a skin color change after the first few sessions. Normally, you will have a good base tan in 6-10 sessions. Then one or two sessions a week thereafter will maintain your tan year round. There are special cells in the skin called melanocytes. Ultraviolet B rays stimulate these cells and cause them to produce melanin. As these cells migrate to the surface of the skin, ultraviolet A rays oxidize them; thus creating a tan. Each of us has a different amount of melanin. Fair-skinned, fair-haired people generally have less than dark-haired, dark-skinned people. This determines, for the most part, how quickly and how dark your skin will tan.