Why does a tan fade an go away?
The “tan,” or pigmentation process, occurs in the epidermis, the top skin layer. The epidermis replaces all its skin cells every 28-30 days. Cells in the inner portion of the top skin layer divide themselves, migrate to the surface, gradually die and slough off. Skin cells contain melanin, and as a result of UV exposure, rise to the surface and flake off. Therefore, a tan can be maintained only by repeated exposure to UV light.
