Full transcript
0:00Do you know what's most fascinating about tanning?
0:02Our skin is literally changing its biology because it's been exposed to
0:06ultraviolet radiation.
0:07And somehow we decided that this was a beauty treatment.
0:10That's the topic of this week's Healthcare Triage
0:18First things first.
0:20Tans are not safe.
0:21The tan is your skin's protective response to ultraviolet radiation exposure.
0:25And before you yell, thanks, Captain Obvious.
0:28Hear me out.
0:28in the American Academy of Dermatology 2026 Practice Safe Sun survey,
0:33about 52% of respondents believed at least one tanning myth.
0:3729% said tanning is safe if you don't burn, and 19% said
0:42a base tan can prevent sunburn or reduce the risk of skin cancer.
0:46That first one is especially interesting because burning is not a prerequisite
0:51for UV damage.
0:52Ultraviolet radiation can damage DNA and skin cells
0:55without getting to the point of a sunburn, and exposure to UV
0:59radiation is associated with several skin cancers, and this may or
1:02may not surprise you, but indoor tanning does not get a special exemption here.
1:06Both ultraviolet radiation from the sun and artificial sources
1:10such as tanning beds and sun lamps have been classified as known carcinogens.
1:15Indoor tanning equipment can emit UVA and UVB radiation
1:19in amounts similar to sunlight, and in some cases, stronger than sunlight.
1:23Indoor tanning is associated with melanoma and non melanoma skin
1:27cancers, with an estimated 58% increased risk of squamous cell
1:32carcinoma and a 24% increased risk of basal cell carcinoma.
1:36Among indoor tanners, using indoor tanning beds before age 20
1:40has been associated with a large increase in the risk of developing
1:44melanoma, with data suggesting that risk increases with each use.
1:48And yes, this applies even if you never burn.
1:51Indoor tanning has declined over the years,
1:53which is good news, but it hasn't disappeared.
1:55The AAD estimates that approximately 7.8 million adults
1:59in the United States still engage in indoor tanning,
2:02and according to 2018 data, about a quarter of U.S.
2:05adults who reported any indoor
2:07tanning said they had tanned 25 or more times in a year.
2:11So if tanning is a problem, what about sunscreen?
2:14Sunscreen has somehow become one of the most misunderstood products in medicine.
2:18There are people online claiming sunscreen is toxic, unnecessary,
2:22causes cancer, interferes with vitamin D, or is basically a chemical conspiracy
2:27between big lotion and the dermatology industrial complex.
2:31And there are people who seem to think sunscreen is magical armor that allows you
2:35to lie on a beach for eight consecutive hours without consequences.
2:39Neither approach is particularly useful.
2:41Let's start with the big one.
2:43Does sunscreen cause cancer?
2:45No. There's no evidence that sunscreen itself causes cancer.
2:48There have been, recalls
2:50a particular sunscreen products because of contamination with benzene.
2:53But benzene is not normally an ingredient in sunscreen.
2:56There are various legitimate questions about individual sunscreen
3:00ingredients and about how different formulations behave.
3:03Importantly, concerns about hormone disruption
3:06have largely come from laboratory or animal research involving high
3:10concentrations, and there's not currently any definitive evidence
3:14establishing that sunscreen ingredients cause hormone disruption in humans.
3:17Some sunscreen ingredients can,
3:19however, cause skin irritation or allergic reactions in some people.
3:23sunscreens also aren't all the same.
3:25Chemical sunscreens use active ingredients that absorb UV radiation.
3:29Mineral sunscreens use ingredients such as zinc oxide or titanium dioxide.
3:34Hybrid products combine approaches.
3:37Different formulations have different characteristics,
3:40So if you're standing in the sunscreen aisle staring at approximately 47 bottles
3:43that all appear to be making the same promise.
3:45Practical advice is to look for broad spectrum protection, meaning protection
3:50against both UVA and UVB and an SPF of at least 30.
3:54And speaking of SPF,
3:56that's another thing about sunscreen that is largely misunderstood.
3:59SPF numbers are not linear.
4:02SPF 15 blocks about 93% of UV radiation, SPF
4:0730 blocks about 97%, and SPF 50 blocks about 98%.
4:13So SPF 50 is not literally twice as protective as SPF 25,
4:17and SPF 100 is not a magical force field And perhaps the biggest catch?
4:21That SPF protection depends heavily on applying the product.
4:25In the same amount that was used on testing.
4:28A sunscreens SPF is measured
4:30using about two milligrams of product per square centimeter of skin.
4:34For an adult, that can translate to roughly an ounce of sunscreen
4:38to cover the exposed body.
4:39Studies have found that people in real life apply substantially less than that.
4:43So if your strategy is to put three microscopic dots of sunscreen
4:47on your forehead, rub them around until your skin looks
4:50approximately moisturized and declare victory.
4:52You may be in trouble.
4:54Also, sunscreen has to be reapplied.
4:56Not because sunscreen companies are trying to bankrupt you
4:59through lotion consumption,
5:01but because sunscreen can be removed by swimming, sweating and friction.
5:05And protection does not last all day with the single application.
5:08In fact, you should be reapplying approximately every two hours.
5:12But even more than that if you're swimming or sweating a lot.
5:14Which brings me to this shocking news.
5:17Waterproof sunscreen does not exist.
5:20Water resistant sunscreen does.
5:23Products labeled water resistant are tested for either 40
5:26or 80 minutes during swimming or sweating, depending on the product.
5:30After that, you got to reapply.
5:31Yet another myth is that sunscreen is only necessary when it's hot and sunny.
5:36Unfortunately, UV radiation does not care whether you're enjoying a 95 degree
5:41beach day or standing outside in a fleece jacket
5:43wondering why you voluntarily live somewhere with winter.
5:46Clouds can reduce some UVB, but do not eliminate UV
5:50exposure, and snow can even reflect UV radiation.
5:53Higher elevations can also increase UV exposure.
5:57Now let's chat about skin tone.
5:59Because another sunscreen myth is the people with darker
6:01skin don’t need it Melanin provides some natural protection
6:05against UV radiation, but darker skin does not make someone immune
6:08to sunburn, skin cancer, or other effects of UV exposure.
6:12And there's another argument
6:13you may have heard if I were sunscreen, how will I get enough vitamin D?
6:18This one requires a little nuance.
6:19While UVB exposure helps the body make vitamin D data,
6:24do not support deliberately sunbathing as a strategy for maintaining
6:27levels, particularly given the trade off with cancer risk.
6:31Adequate vitamin D can be obtained through diet, so you don't have to choose
6:35between protect my skin and have vitamin D, you can just eat food.
6:39And note that regular sunscreen
6:40use does not appear to eliminate vitamin D production in real world use anyway.
6:44sunscreen is important,
6:45but it shouldn't be treated as the primary or only method of UV protection.
6:49Sunscreen use does not block all UV radiation.
6:52It works best alongside shade, protective
6:56clothing, and avoiding excessive UV exposure.
6:59The goal should never be to figure out which sunscreen allows you
7:02to spend the maximum possible amount of time in the sun.
7:05The goal is to reduce your UV exposure while still allowing you to,
7:09you know, go outside and be a human being.
7:11And sunscreen isn't just about cancer, even though that's the larger concern UV
7:15exposure also contributes to premature skin aging and other skin damage.
7:19Which brings us back to that tan.
7:22Tan can look good to you.
7:23I'm not going to pretend
7:24humans don't have aesthetic preferences, but biologically, a ten
7:28is a response to UV exposure, and deliberately tanning
7:31means deliberately exposing your skin to UV radiation.
7:34There is no special category of safe tanning that happens because you're young,
7:39or because you don't burn, or because you got a base tan first,
7:42or because the UV came from a tanning bed instead of the sun.
7:46You can go to the beach, you can hike, you can garden, and you can ski.
7:50But don't confuse
7:50enjoying the outdoors with deliberately maximizing your UV exposure.
7:55Don't assume that a tan means your skin is protected,
7:57that a lack of sunburn means
7:58there was no damage, or that sunscreen gives you permission to
8:01stay in the sun indefinitely
8:03Use broad spectrum sunscreen.
8:05Apply enough of it. Reapply it.
8:07Wear a hat, find some shade, and stay out of the tanning beds.
8:11Hey, do you like this episode
8:12you might enjoy this previous episode on Does Sunscreen Need Safety Evaluation?
8:17We'd appreciate it if you'd like the video and subscribe to the channel down below.
8:20Really go do it.
8:22Maybe go on over to Patreon.com/HealthcareTriage
8:25where you can help support the show and make it bigger and better.
8:28We'd like to thank our research associates Edward Liljeholm
8:31and Christopher Learn and of course our Surgeon Admiral, Sam.