12 Outrageous Tanning Myths That Should Be Burned Immediately

Sunlight is a form of radiation. And when that radiation hits your skin, it can mutate the DNA in your skin cells. Period.

Sun damages your cells no matter what your skin color, though dark-skinned people get less damage than the light-skinned. That's because dark skin has more of a pigment called melanin, which helps slow DNA damage.

When light-skinned people get a tan, it's because their skin has made more melanin in response to being hit by the sun's ultraviolet (UV) rays. The photo above, taken with a camera that filters out all light except for UV, shows clusters of melanin (aka freckles) absorbing those rays.

"A suntan is a sign that skin has already been damaged," as a new JAMA article put it. "And tanned skin can continue to be damaged when exposed to UV rays."

Many websites and ads twist that idea, claiming that a suntan is "nature's sunscreen" — as if it blocks further damage.

"It makes no sense," Lindsey Bordone, a dermatologist at Columbia University, told BuzzFeed News. "That's like saying you're protecting yourself from lung cancer by putting a filter on a cigarette."

The sun's radiation hits our skin in two kinds of rays: UVA and UVB.

UVB rays have shorter wavelengths, which means they have more energy and are more damaging to the top layers of skin cells. Scientists used to think that only UVB rays increased the risk of cancer and premature aging. But more recent research shows that UVA rays are also harmful.

In fact, studies of indoor tanning — which uses mostly UVA rays — have found that it greatly increases the risk of both melanoma and non-melanoma skin cancers.

Yes, it's true that your body produces vitamin D in response to sun exposure. (Specifically, vitamin D production is triggered by UVB rays — which aren't used in most tanning beds!) And yes, getting enough vitamin D is important for building strong bones and a robust immune system.

But here's the thing: Tanning isn't necessarily a great source of vitamin D. "The amount of outdoor sun exposure needed for meaningful vitamin D production depends on many factors, including time of day, time of year, latitude, altitude, weather conditions, a person’s skin type, amount of skin exposed to the sun" and other factors, the surgeon general says.

Plus, there are lots of other ways to get your vitamin D — without the skin cancer risk. Fatty fish, egg yolks, and calf liver are all high in vitamin D, as are fortified milk, yogurt, juices. If you're really concerned about low vitamin D, you can also try a dietary supplement.

This is one of the strangest tanning myths out there. The idea is that light rays stimulate your thyroid hormone, somehow causing weight loss.

"I have never in my life heard this," said Bordone, the Columbia dermatologist. "It'd be much smarter to just go walking."

The ingredients of most sunscreens have been on the market for decades, and there's little evidence that they are unsafe.

If you hear about "toxic" or "poisonous" sunscreen, it's probably concerning products that contain oxybenzone, a chemical that protects your skin by absorbing UV rays. There are some studies (though far from conclusive) suggesting that oxybenzone affects your hormones.

If you're worried about these potential risks, however small, Bordone suggests choosing sunscreens that instead contain metals — usually titanium dioxide or zinc oxide — which are often found in products meant for babies. Rather than being absorbed by your skin, these sunscreens sit on top of your skin and reflect the sun's rays.

The best refutation of this myth comes from a medical case study published in 2012.

A 69-year-old man, pictured above, was a delivery truck driver for 28 years. Because UVA rays can pass through windows, the left side of his face became far more wrinkled than the right side.