New research uncovers the science behind why the body's tanning process does not occur immediately after sun exposure, but only after a few hours or even days.

The mechanism that repairs our DNA takes precedence over all other systems in the cell, temporarily inhibiting the pigmentation mechanism. Only after the cells repair the genetic information to the best of their ability do they begin to produce the increased melanin, according to the study in the Journal of Investigative Dermatology.

“We have two mechanisms designed to protect the skin from exposure to dangerous UV radiation,” says researcher doctoral student Nadav Elkoshiof the Department of Human Molecular Genetics and Biochemistry at Tel Aviv University’s Faculty of Medicine in a news release. “The first mechanism repairs the DNA in the skin cells damaged by the radiation, while the second mechanism involves increased production of melanin, which darkens the skin in order to protect it from future exposure to radiation.”

To test their hypothesis, the researchers activated the DNA repair mechanism in both animal models and human skin tissues. In both, a tan developed even without any exposure to UV radiation, substantiating their findings.

Read more at Practical Dermatology >>