The Real Reason Not Everyone Can Get A Tan

Spend a summer afternoon snoozing under the midday sun, and you're sure to wake up a few shades darker than when you lay down. For some, waking up to a glowing tan is just what they hoped for, while for others, waking up to a painful red burn is agonizing. What's the difference? Why do some people tan easily while others — especially those with fair skin — can basically count on turning pink, not brown, under the sun?

The answer has to do with melanocytes, the cells found at the bottom part of the epidermis (the outermost layer of skin), which produce melanin. Melanin is a brown pigment that is responsible for skin color, as well as for protecting the skin from the sun's UV rays (via Very Well Health). Light-skinned people have less melanin, while darker-skinned people have more.

When skin is exposed to the sun's UV rays, melanocytes kick into high gear, producing more melanin, and distributing it to the surface of the skin as a way of protecting the inner parts of the skin cells. That accumulation of melanin is what causes a tan (via SELF).

Aleksandar Sekulic, M..D, principal for Stand Up To Cancer's Melanoma Research Alliance Dream Team and Mayo Clinic dermatologist, told SELF, "What the cells do with this pigment they received as a gift is pile it all on top of the cell's nucleus, like an umbrella." The longer you stay out in the sun, the harder your melanocyte cells work to produce melanin, the bigger the "pile-up" becomes, and the darker you get.

While most people have the same number of melanocytes, the amount of melanin their cells actually produce, and how well it protects, can vary significantly. Sekulic explains "The lighter the umbrella, the more holes it has in it. Not everybody will have the same capacity to protect themselves."

That is why people with lighter skin are often more likely to burn than tan, and are also much more susceptible to skin damage as a result of UV rays (via Cancer.org). If you're a fair-skinned "burner" and still long for that glowy, tanned look — play it safe and opt for a tanning lotion instead.