DNA damage is at least one of the signals generated by ultraviolet radiation that stimulates pigmentation production (tanning) in human skin. Don’t damage your p53 (it’s a tumor suppressor).

The photoprotective tanning response is functionally similar to the SOS response described in bacteria. The SOS response results from DNA damage in which the cell cycle is arrested and DNA repair and adaptive mutagenesis is induced. Adaptive mutations may reflect an inducible mechanism that generates genetic variability in times of stress.  Basically, it’s an ancient survival mechanism. While there are benefits, there are also negative consequences. As such, it’s best not to stress the skin with too much sunshine. As I’ve previously discussed in a review paper, small amounts of sun exposure are beneficial, including to the skin’s adaptive immune system (T-cells), but once you start tanning, the negative effects on the skin begin.

DNA damage stimulates pigmentation, at least in part, through up-regulation of tyrosinase mRNA and protein levels. Interestingly, scientists have found this response can be induced in the absence of DNA damage by treatment of melanocytic cells and intact skin with small DNA fragments, particularly thymidine dinucleotides, pTpT. Application of these DNA fragments have been found to provide a photoprotective tan to human skin cells without the harmful effects of ultraviolet radiation.

For my fellow nerds out there who like to learn about cellular and subcellular signaling pathways in the skin, here’s what happens (from Dr. Suzanne Clancy, Ph.D): Incident UV radiation on the skin causes two classes of DNA lesions: cyclobutane pyrimidine dimers (CPDs) and 6-4 photoproducts (6-4 PPs). Both of these lesions distort DNA’s structure, introducing bends or kinks and thereby impeding transcription and replication. Relatively flexible areas of the DNA double helix are most susceptible to damage. One “hot spot” for UV-induced damage is found within a commonly mutated oncogene, the p53 gene. The p53 gene is a so-called tumor suppressor gene. If damaged, tumors more easily develop.

So coverup in the sun, and/or wear a sunscreen. Before and after going out in the sun, use a topical product that contains a variety of antioxidants, including but not limited to Vitamin C, to replace the antioxidants that were degraded by the sunlight. Using an antioxidant product, such as NeoGenesis Recovery and the new Neogenesis Vitamin C/Antioxidant product that will soon be released, will help to protect and repair DNA (and proteins and lipids), and may reduce your chances of developing cancer.