Tanning oils themselves are not harmful to the human body; however they are often applied when people are over exposing their skin to the sun. This can result in serious problems. Over exposure to the harmful rays of the sun can result in the development of skin cancer cells, leading to complications and illness later in life.
Using tanning oils, especially those which do not contain Sun Protection Factor (SPF), increases the absorption of Ultraviolet A (UVA) and Ultraviolet B (UVB) rays into the body, increasing the risk of sun burns and skin cancer.