Do you know what's most fascinating about tanning?

Our skin is literally changing its biology because it's been exposed to ultraviolet radiation. And somehow we decided that this was a beauty treatment.

That's the topic of this week's Healthcare Triage First things first. Tans are not safe. The tan is your skin's protective response to ultraviolet radiation exposure.

And before you yell, thanks, Captain Obvious. Hear me out. in the American Academy of Dermatology 2026 Practice Safe Sun survey, about 52% of respondents believed at least one tanning myth. 29% said tanning is safe if you don't burn, and 19% said a base tan can prevent sunburn or reduce the risk of skin cancer. That first one is especially interesting because burning is not a prerequisite for UV damage.

Ultraviolet radiation can damage DNA and skin cells without getting to the point of a sunburn, and exposure to UV radiation is associated with several skin cancers, and this may or may not surprise you, but indoor tanning does not get a special exemption here. Both ultraviolet radiation from the sun and artificial sources such as tanning beds and sun lamps have been classified as known carcinogens. Indoor tanning equipment can emit UVA and UVB radiation in amounts similar to sunlight, and in some cases, stronger than sunlight.

Indoor tanning is associated with melanoma and non melanoma skin cancers, with an estimated 58% increased risk of squamous cell carcinoma and a 24% increased risk of basal cell carcinoma. Among indoor tanners, using indoor tanning beds before age 20 has been associated with a large increase in the risk of developing melanoma, with data suggesting that risk increases with each use. And yes, this applies even if you never burn.

Indoor tanning has declined over the years, which is good news, but it hasn't disappeared. The AAD estimates that approximately 7.8 million adults in the United States still engage in indoor tanning, and according to 2018 data, about a quarter of U. S. adults who reported any indoor tanning said they had tanned 25 or more times in a year.

So if tanning is a problem, what about sunscreen? Sunscreen has somehow become one of the most misunderstood products in medicine. There are people online claiming sunscreen is toxic, unnecessary, causes cancer, interferes with vitamin D, or is basically a chemical conspiracy between big lotion and the dermatology industrial complex.

And there are people who seem to think sunscreen is magical armor that allows you to lie on a beach for eight consecutive hours without consequences. Neither approach is particularly useful. Let's start with the big one.

Does sunscreen cause cancer? No. There's no evidence that sunscreen itself causes cancer.

There have been, recalls a particular sunscreen products because of contamination with benzene. But benzene is not normally an ingredient in sunscreen. There are various legitimate questions about individual sunscreen ingredients and about how different formulations behave.

Importantly, concerns about hormone disruption have largely come from laboratory or animal research involving high concentrations, and there's not currently any definitive evidence establishing that sunscreen ingredients cause hormone disruption in humans. Some sunscreen ingredients can, however, cause skin irritation or allergic reactions in some people. sunscreens also aren't all the same. Chemical sunscreens use active ingredients that absorb UV radiation.

Mineral sunscreens use ingredients such as zinc oxide or titanium dioxide. Hybrid products combine approaches. Different formulations have different characteristics, So if you're standing in the sunscreen aisle staring at approximately 47 bottles that all appear to be making the same promise.

Practical advice is to look for broad spectrum protection, meaning protection against both UVA and UVB and an SPF of at least 30. And speaking of SPF, that's another thing about sunscreen that is largely misunderstood. SPF numbers are not linear.

SPF 15 blocks about 93% of UV radiation, SPF 30 blocks about 97%, and SPF 50 blocks about 98%. So SPF 50 is not literally twice as protective as SPF 25, and SPF 100 is not a magical force field And perhaps the biggest catch? That SPF protection depends heavily on applying the product.

In the same amount that was used on testing. A sunscreens SPF is measured using about two milligrams of product per square centimeter of skin. For an adult, that can translate to roughly an ounce of sunscreen to cover the exposed body.

Studies have found that people in real life apply substantially less than that. So if your strategy is to put three microscopic dots of sunscreen on your forehead, rub them around until your skin looks approximately moisturized and declare victory. You may be in trouble.

Also, sunscreen has to be reapplied. Not because sunscreen companies are trying to bankrupt you through lotion consumption, but because sunscreen can be removed by swimming, sweating and friction. And protection does not last all day with the single application.

In fact, you should be reapplying approximately every two hours. But even more than that if you're swimming or sweating a lot. Which brings me to this shocking news.

Waterproof sunscreen does not exist. Water resistant sunscreen does. Products labeled water resistant are tested for either 40 or 80 minutes during swimming or sweating, depending on the product.

After that, you got to reapply. Yet another myth is that sunscreen is only necessary when it's hot and sunny. Unfortunately, UV radiation does not care whether you're enjoying a 95 degree beach day or standing outside in a fleece jacket wondering why you voluntarily live somewhere with winter.

Clouds can reduce some UVB, but do not eliminate UV exposure, and snow can even reflect UV radiation. Higher elevations can also increase UV exposure. Now let's chat about skin tone.

Because another sunscreen myth is the people with darker skin don’t need it Melanin provides some natural protection against UV radiation, but darker skin does not make someone immune to sunburn, skin cancer, or other effects of UV exposure. And there's another argument you may have heard if I were sunscreen, how will I get enough vitamin D? This one requires a little nuance.

While UVB exposure helps the body make vitamin D data, do not support deliberately sunbathing as a strategy for maintaining levels, particularly given the trade off with cancer risk. Adequate vitamin D can be obtained through diet, so you don't have to choose between protect my skin and have vitamin D, you can just eat food. And note that regular sunscreen use does not appear to eliminate vitamin D production in real world use anyway. sunscreen is important, but it shouldn't be treated as the primary or only method of UV protection.

Sunscreen use does not block all UV radiation. It works best alongside shade, protective clothing, and avoiding excessive UV exposure. The goal should never be to figure out which sunscreen allows you to spend the maximum possible amount of time in the sun.

The goal is to reduce your UV exposure while still allowing you to, you know, go outside and be a human being. And sunscreen isn't just about cancer, even though that's the larger concern UV exposure also contributes to premature skin aging and other skin damage. Which brings us back to that tan.

Tan can look good to you. I'm not going to pretend humans don't have aesthetic preferences, but biologically, a ten is a response to UV exposure, and deliberately tanning means deliberately exposing your skin to UV radiation. There is no special category of safe tanning that happens because you're young, or because you don't burn, or because you got a base tan first, or because the UV came from a tanning bed instead of the sun.

You can go to the beach, you can hike, you can garden, and you can ski. But don't confuse enjoying the outdoors with deliberately maximizing your UV exposure. Don't assume that a tan means your skin is protected, that a lack of sunburn means there was no damage, or that sunscreen gives you permission to stay in the sun indefinitely Use broad spectrum sunscreen.

Apply enough of it. Reapply it. Wear a hat, find some shade, and stay out of the tanning beds.

Hey, do you like this episode you might enjoy this previous episode on Does Sunscreen Need Safety Evaluation? We'd appreciate it if you'd like the video and subscribe to the channel down below. Really go do it.

Maybe go on over to Patreon.com/HealthcareTriage where you can help support the show and make it bigger and better. We'd like to thank our research associates Edward Liljeholm and Christopher Learn and of course our Surgeon Admiral, Sam.