Awareness of the dangers and damage caused by the sun’s ultraviolet rays seems to be growing. Still, many people treat a tan as a safe form of sun exposure because bronzed skin may not peel or hurt like a sunburn. According to the National Health Interview Survey, about 39% of women and 29% of men in the United States had intentionally tried to tan themselves in the past year.
To be clear, a tan is not safe. In fact, skin darkens from sun exposure because it’s been injured and it’s attempting to protect itself from further damage.
Tanning is a threat on different fronts
Tanning also raises the risk for skin cancer.
Tans and sunburns are caused by exposure to two different kinds of UV rays emitted by the sun. Ultraviolet B rays cause sunburns, and ultraviolet A rays penetrate more deeply and bring about a tan. Both kinds of UV rays can trigger DNA mutations that increase the risk of cancer.
UVA rays injure the skin in other ways, too. Their radiation suppresses the immune system in ways that also raise the risk for cancer.
UVA rays are also involved in eroding collagen and elastin molecules and causing wrinkles and brown spots.
“But I need my vitamin D”
You may be asking, “But what about vitamin D?” While it’s important to get enough of it – adults ages 19 to 70 should aim to get 600 international units (IU) of vitamin D per day – there are lots of misconceptions about how to go about getting it.
Vitamin D is synthesized in the skin after it’s exposed to the sun’s UVB rays. Generally, adults with lighter skin can enough vitamin D after being outside for 10 minutes at midday in the spring and summer, according to a 2010 study.
Other studies have found little evidence to support the belief that using sunscreen impairs the body’s ability to make vitamin D from exposure to the sun.
Older adults and those with darker skin may not be able to synthesize the recommended amount of vitamin D from sunlight, so it’s safer to get it from supplements and foods like egg yolks, salmon, and fortified juices and milk.
What sufficient sun protection looks like
It’s worth saying again (and again): The best protection for your skin from UVA and UVB rays is a broad-spectrum sunscreen with an SPF of at least 30. Use a tinted mineral sunscreen if you have darker skin because the iron oxide it contains protects the skin from other wavelengths of light that can contribute to hyperpigmentation and other skin conditions common to darker skin.
And make sure you’re using enough of it. You should be applying one ounce – or enough to fill a shot glass – of sunscreen over all exposed skin. And reapply every two hours. If you’re swimming or sweating, make it every hour.