Tanning is basically the immediate and long-term pigment darkening that occurs as a result of exposure to UV radiation. HAVING A TAN DOES NOT PROTECT THE SKIN FROM UV RADIATION NOR DOES IT DECREASE THE RISK OF SKIN CANCER! There is a delayed tanning effect that occurs about 3 days after sun exposure. This effect gives a sun protection factor (SPF) of about 3, which provides a small amount of protection from sunburn. However, this slight increase in protection is not sufficient to decrease the risk of cancer and photoaging from sun exposure.
Indoor tanning is even riskier than tanning from the sun. The increased risk is due to the fact that most tanning lamps emit primarily UV-A radiation, the type less likely to cause sunburn but more likely to cause skin cancer. This allows users to acquire even more UV exposure than they would normally be able to get from the sun and thus puts them at an even higher risk for cancer, photoaging, and immunosuppression. Additionally, the body’s response to UV-A radiation does not even provide protection from sunburn (mainly caused by UV-B radiation).
“The American Academy of Dermatology opposes indoor tanning and supports a ban on the nonmedical production and sale of indoor tanning devices.” The WHO considers tanning lamps carcinogenic.