Sun Tan What it is:
There is no such thing as a safe tan. The increase in skin pigment, called melanin, which causes the tan color change in your skin is a sign of damage.

Why it happens:
Once skin is exposed to UV radiation, it increases the production of melanin in an attempt to protect the skin from further damage. Melanin is the same pigment that colors your hair, eyes, and skin. The increase in melanin may cause your skin tone to darken over the next 48 hours.

Skin tones that are capable of developing a tan, typically skin types II through V, will probably darken in tone within two days.

The Bottom Line:
Evidence suggests that tanning greatly increases your risk of developing skin cancer. And, contrary to popular belief, getting a tan will not protect your skin from sunburn or other skin damage. The extra melanin in tanned skin provides a Sun Protection Factor (SPF) of about 2 to 4; far below the minimum recommended SPF of 15.