Many of us humans have a weird obsession with getting tanned in the summer, risking it all to become a few shades darker, even if it means permanently damaging our skin. Which is pretty wild, considering how temporary a tan is. But how do tans work, anyway, and how long does a tan last, really?
Essentially, when you spend enough time under the sun, your body starts calling upon cells called melanocytes, which are located in your epidermis, the outermost layer of your skin. Those melanocytes then pump out a dark layer of pigment called melanin in an attempt to shield the deeper layers of your skin from sun damage. Put simply, a tan is just a bunch of extra pigment (melanin) settled in the outermost layer of your skin.
Thanks to the cycle of life, your skin cells, including those covered with melanin, constantly replace themselves (some estimates even suggest that your epidermis wholly renews itself about every 27 days). During that regeneration process, the cells that were doused with melanin — which again, are lingering in the top layer of your epidermis — naturally begin to exfoliate themselves within seven to ten days. Once that process begins, and if you stay out of the sun, your tan will gradually fade away.
As for where all that tanned skin goes, well, all over the place. According to a 2011 study, over the course of a lifetime, most people shed roughly half of their body weight in skin flakes, which float around our homes, burrow into our couches and drift about in the air we breathe (and just like that, I refuse to breathe ever again).
If you want your tan to last longer than about a week or so, counterintuitive as it may sound, gently exfoliating every few days — using an exfoliating Prep Scrub before you shave, for example — can help maintain the glow of sun-kissed skin, since dead cells atop that bronzed skin can make your tan appear dull and just generally more pale. Or you could just slap on some bronzer, which is the safest way to get some color, anyway.
Crap, I just breathed. Gross.