Sunscreen myths: Higher SPFs are not enough, cloudy days are dangerous

Oct 09, 2023

It's summertime in Florida, which means fun in the sun, cool drinks, and, possibly, skin cancer.

That's an exaggeration, of course. Floridians don't wait for summer.

Being outside is great. You get exercise, you experience the beauty of the Sunshine State, and you reduce your stress. Some of us have to work outside for long periods of time, some of us enjoy long hikes or working in the garden, and some of us just want to touch some grass for a few minutes. But you need to protect your skin while you do it.

That smooth, even tan you got by the pool? That is, essentially, a radiation burn from the sun's harmful ultraviolet (UV) rays, and too much exposure can cause out-of-control growth of abnormal cells and may lead to the most commonly diagnosed cancer in the U.S. The American Cancer Society estimates that 9,640 people will be diagnosed with melanoma of the skin in Florida this year. At least two people die of skin cancer in the United States every hour, and one in five Americans will develop skin cancer by the time they turn 70, according to The Skin Cancer Foundation.

But skin cancer is also the most easily preventable cancer, as long as you know what you're doing.

Here are the biggest myths about sunscreen.

"Sunscreen isn't an all-protective force field," said Dr. Anne K. Julian, Ph.D., with the Division of Cancer Prevention and Control. Sunscreen is intended to be used along with other safety measures such as covering up, wearing wide-brimmed hats, staying in the shade, and avoiding the times of the day when the sun is the most intense (10 a.m. to 4 p.m.). Sunglasses can help reduce the risk of cataracts from UV rays.

It is especially important to protect children and adolescents from too much sun exposure, according to the American Cancer Society, as bad sunburns when you're young can increase later risks of melanoma, the deadliest form of skin cancer.

Many sunscreens sound good from the label but may offer little to no actual protection. The nonprofit organization Environmental Working Group (EWG), which tests sunscreens every year, has found in the past that many sunscreens marketed for children were more harmful than helpful and actually scored too low to be fully effective.

The Food and Drug Administration has warned about some common sunscreen ingredients because of concerns that they may actually harm skin or disrupt the hormone system, such as oxybenzone (and some studies have suggested that oxybenzone may hurt coral reefs once it gets in the water).

Sunscreens are rated for their sun protection factor, or SPF. The Centers for Disease Control recommends using one with an SPF of at least 15, the American Cancer Society suggests 30 or higher.

But the SPF rating can be misleading. The sun emits two three different types of UV rays and SPF rankings only measures how well a sunscreen blocks one of them: UVB rays, the main cause of sunburn and the most dangerous skin cancers. "SPF values do not reflect a product’s ability to protect from UVA rays, which penetrate the skin more deeply and are associated with skin aging and cancer," the EWG site says. Look for broad-spectrum sunscreens that filter out both UVA and UVB rays.

As for higher SPF values, in 2011 the FDA called SPF labels higher than 50 "inherently misleading" as after an SPF of 30 there's not much difference in protection, the higher concentration of some ingredients could add health risks, and people may get a false sense of security from a high number and stay in the sun longer.

Studies have shown that people using sunscreen frequently get burned because they don't use as much sunscreen as they should, or they don't reapply it, which drastically lessens its effectiveness.

"That means a shot glass full to cover the full body, a fourth to a half teaspoon for the face," Julian said, adding that people should use more than they think they need to. According to the FDA, an average-sized adult or child needs at least one ounce of sunscreen to evenly cover the body from head to toe.

"Apply sunscreen at least 15 minutes before you go outside," Julian said, "Reapply it at least every two hours, and more often if you are sweating or getting in and out of the water."

Sunscreens are not recommended for infants, who are at more risk than adults from sunscreen side effects such as a rash. Your best protection for infants under six months is to keep them covered up and out of the sun.

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Sunscreen isn't makeup. Think of it more as a non-prescription drug, Julian said, intended to protect the skin. Even aside from cancer prevention, sun exposure means premature aging and who wants that, whatever your gender?

It's really not. Some sunscreens contain coconut oil, but by itself, it's not enough.

"Coconut oil may extend the time to burn for some individuals," Julian said, "but the level of UV protection is very low and may be highly variable by source, so don’t rely on coconut oil to protect your skin!"

Similarly, don't rely on self-tanning lotions or spray tans to help prevent skin cancer. They won't.

After five sunburns your risk of melanoma doubles, and establishing a "base tan" at a tanning salon is still doing damage to your skin. Frequent tanning and sunburn actually increase the likelihood of skin damage and skin cancer.

People with lighter skin are more likely to get skin cancer from exposure to the sun or taking bulbs, but everyone with skin can develop it.

"Skin cancers are less prevalent in nonwhite racial ethnic groups," according to Dr. Andrew Alexis, chair of the Department of Dermatology at Mount Sinai St. Luke’s and Mount Sinai West in New York City, "but when they occur, they tend to be diagnosed at a later stage. As a result, the prognosis is worse."

People of African, Asian, Latino, Mediterranean, Middle Eastern and Native American descent all have lower percentages of skin cancer, but because of the lack of awareness and the higher incidents of skin cancer on areas that don't generally get much sun (palms of the hands, soles of the feet, under finger and toe nails, etc) the rate of late-stage detection is much higher. Black patients with melanoma have an estimated five-year melanoma survival rate of 70 percent, versus 94 percent for white patients, according to the American Cancer Society.

Anyone living in Florida long enough knows you can get sunburnt on a cloudy day. Especially as you get closer to the equator, there are strong UV rays all year, and while clouds can block some UV, over 90% of it can still get through.

You may want to wear sunscreen even if you're not going outside if you spend a lot of time near windows that receive direct sunlight. UV rays aren't only dangerous from above. UV rays can bounce off open water, sand, snow, pavement and even grass.

To see if you're at risk or sunburn or skin damage, check your local UV Index. The UV Index is calculated by the National Weather Service; any weather app should include the information or you can check here. The higher the number, the bigger the chance of sunburn and the less time it takes to damage your skin. If your local UV Index is 3 or more you should put on sunscreen, cover up and stay in the shade, especially if you're light-skinned or prone to sunburn. Over 6, everyone should wear sunscreen.

In Florida, UV indexes of 10 are common, especially in the summer.

C. A. Bridges is a Digital Producer for the USA TODAY Network, working with multiple newsrooms across Florida. Local journalists work hard to keep you informed about the things you care about, and you can support them by subscribing to your local news organization. Read more articles by Chris here and follow him on Twitter at @cabridges