Skin cancer cases are on the rise throughout the United States, a trend that has been linked at least in part to the popularity of tanning booths, particularly among teens and young adults.
But even people who think they're protecting their skin, typically are not doing enough to prevent skin cancer, said DeAnn Lazovich, a University of Minnesota skin cancer expert.
Lazovich, an associate professor in the division of Epidemiology and Community Health, said many people think sunscreen should be their first choice to guard against the sun's harmful ultraviolet radiation.
But it should be their last, said Lazovich, whose research has been used by state and federal agencies to formulate sun safety policies and guidelines.
"The first choice ought to be clothing, hats, avoidance of the sun by staying in the shade [and] avoiding the peak hours," she said.
Only after taking those measures, Lazovich said, should a person reach for sunscreen.
The problem with relying solely on sunscreen, she said, is that it may give people a false sense of invincibility.
Lazovich said many people often view sunscreen use as a way to stay out in the sun longer without getting burned. But even tanned skin is a sign of skin damage, which accumulates with years of sun exposure, she said.
"If you're constantly in the sun, over your lifetime you are getting exposed to the sun and you may still be experiencing some damage over time," Lazovich said. "Even in the absence of sunburn, that could still lead to skin cancer."
Many people do not properly use sunscreen, which a person should apply to their skin 30 minutes before going outside, and reapply at least every two hours.
Studies show that people tend to ignore those guidelines and also apply far less sunscreen than recommended, Lazovich said.
"So, if you use a quarter to a half [of the recommended amount] of sunscreen that's labeled SPF 30, you might be only getting an SPF of around 5 to 7," she said.
The Centers for Disease Control and Prevention recommends using a broad spectrum sunscreen with at least an SPF of 15. SPFs higher than 50 are not necessary, and the products usually cost more.
A general rule of thumb, Lazovich said, is to apply enough sunscreen to fill a shot glass.
"If that's hard to think about, one could think about applying about a tablespoon to the big body parts and a teaspoon to the smaller body parts," she said.
A person's trunk, front, back and legs would qualify as big body parts. The arms and face combined would be a small body part.
But Lazovich does not recommend sunscreen sprays.
"If you watch it being sprayed, you see it sort dissipating into the air, so it's not actually getting on the person," she said.
The U.S. Food and Drug Administration announced this year that it is taking a closer look at spray-on sunscreens due to concerns they do not work as well and the effect the aerosol chemicals may have on the lungs.
Lazovich said people who use sunscreen sprays should first squirt the product into their hands to gauge how much sunscreen they are applying to their skin.
But she said wearing protective clothing is always going to be a much better approach.
"If keeping yourself covered up greatly reduces your risk of sunburn and skin cancer, why would we need to do anything else?" she asked.
Lazovich isn't naive. She knows it will be hard to convince people that they should limit their time in the sun — let alone avoid it most of the time.
The latest selfie trend makes the challenge clear. "Sunburn art," which involves deliberately using the sun and objects to burn patterns into the skin, is attracting followers.
Understanding how to counter such harmful practices is something Lazovich hopes to address in an upcoming project. She is part of a team of researchers working on developing new skin cancer messages that convince people to take sun exposure more seriously.