February 20, 2015
With spring break on the way, we’re all familiar with the process, right? First you burn, then you burn until you’re purple, then you can’t move for three days, and then you’re #blessed with a “base tan” that protects you from further damage, right? Wrong. Some Yale nerds have determined that the very melanin that gives you that youthful glow is actually fucking your skin up even worse. What’s even weirder is that it does it hours later - long after you’ve left the beach.
Part of the reason UV radiation gives you skin cancer is something called a cyclobutane dimer, or CPD. UV radiation causes these CPDs to attach more information to your DNA, effectively bending it so that it’s information can’t be “read” by other cells (picture the prongs bending in one of those old cables you used to use to connect your computer monitor to the tower). Cells with this fucked up DNA produce more cells with fucked up DNA, and then boom - cancer, the world’s biggest buzzkill.
The melanin in your skin is, in theory, supposed to protect you from these dickbag CPDs. And it does! Kind of.
“If you look inside adult skin, melanin does protect against CPDs. It does act as a shield,” said Douglas E. Brash, clinical professor of therapeutic radiology and dermatology at Yale School of Medicine. “But it is doing both good and bad things.”
What they found is that when UV radiation interacts with melanocytes (the things that produce melanin, duh), enzymes are released that “excite” an electron (maybe they tell it its STD screen came back clean, idk), and the resulting energy fucks up your DNA in the dark the way the Sun does under direct exposure. Basically, the Sun will continue to wreck your shit even hours after you’re no longer in it.
They go on to say that some kind of “evening-after” sunscreen could probably remedy or mitigate the problem, but they have no goddamn idea of what that would look like or how that would work. Basically, stay out of the Sun, forever.
Thus ends your annual reminder that you can get a perfectly fine tan while wearing very strong sunscreen, as the two are not really related.