Sunscreen: Could It Be Toxic??

Sunscreen claims on social media

0:00Wait, so the melanin sites, the cells that make the melanin, then the melanin is like sunscreen for your DNA, like natural sunscreen for your DNA? Yeah, so like this melanin, it's directly responding to the sun, it's moving up there, and it's wanting to protect you from those UV rays, and in essence protects you from the DNA damage that could cause.

0:30Skin cancer. Wow, that's so cool. Hi, I'm Wendy Zuckerman, and this is Science Versus. Today on the show, we're pitting facts against frying in the sun.

0:48We're talking about sunscreen. All over social media, people are telling you to ditch your sunscreen. They say that it's doing us more harm than good. Like, some say that if you really want to be healthy, you shouldn't be blocking out the sun's gorgeous rays at all. You should be going outside and letting the sun help us make that sweet, sweet vitamin D. No sunscreen, no fear. Just me and the light my body was begging for. Vitamin D is free, it's powerful, and it's meant for us.

1:23Others claim that sunscreen itself is straight up toxic, that it seeps dangerous chemicals into our blood, and might even be messing up our hormones. I'm going to show you what they're putting in our sunscreen, and it's going to make you just as mad as it's made me. Most people don't realize how toxic our sunscreens are. Two hours after applying it to the skin, these toxic environmental estrogens can actually be detected in the blood. And this is exactly why I stopped using toxic sunscreens from the grocery store. But of course, a lot of us wear sunscreen to protect our skin from skin cancer.

1:58The problem is that now I'm hearing of scientific studies that apparently show sunscreen could be causing cancer. Ah! What is going on here? When they compare sunscreen users to non-sunscreen users, the sunscreen users faced increased risks of all the major skin cancers. We use more of this chemical sunscreen than we ever had before. Skin cancer rates increasing. You've got to just use your head for a minute. All of this has led people to say, stop buying sunscreen. Or online, you can even find people giving recipes on how to make your own sunscreen at home.

2:33This is your answer. Get that bulls**t out of your life and start using a really good quality sunscreen. So what is going on with sunscreen? Should we use it or not? Is it making us vitamin D deficient and leeching toxins in our blood? And if we still want to use it, are some sunscreens safer than others? When it comes to sunscreen, there's a lot of... Most people don't realise how toxic our sunscreens are. But then, there's science.

3:06Science vs. Sunscreen is coming up. Just after the break. If you have a friend who's worried about sunscreen, maybe share him this episode.

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Oxybenzone and hormone safety

4:12Welcome back. Today on the show, we are looking into whether sunscreens are dangerous. Should we be slapping them on our bodies? To tell us all about it is producer at Science Versus, Michelle Dang. Hey, Wendy. Hey. Michelle, sunscreen, this question of whether sunscreen is safe has been in the zeitgeist for so long. I feel like you've wanted to do this episode for ages. Yeah, I think I pitched it like seven years ago when I was an intern. Wow, no, did you really?

4:43So, it's taken us a while, but we're coming back to it. I know, and you know, as you've been sort of like, I'm getting whispers of the science that you've been finding, and it's making me wonder, you know, have I just been swallowed by big sunscreen, by the sunscreen propaganda machine? It's making me question everything I think I know about sunscreen. I do always hear online Australians talking about Sid the seagull? The seagull? What, you got a problem with Sid? Now, the seagull? No, tell me more.

5:14But the uninitiated Sid the seagull was this seagull that for decades has taught Australians how you've got to put sunscreen on and more broadly protect yourself from the sun. And Sid would tell us, and he says, you've got to slip, slop, slap. Slip, slop, slap. It sounds like a breeze when you say it like that. Slip, slop. So you slip on a T-shirt, you slap on a hat,

5:44and you slop on some sunscreen. I thought it was all, it was like, slip, slop, slop, sunscreen. But yeah, it's a whole array of things you've got to do. Have I been lied to all my life? I mean, presumably sunscreen is protecting my skin, but now we're sort of hearing that it's also getting into my body, these chemicals from the sunscreen getting into my body, causing damage. So what's going on? Where do we begin? Yeah, let's start there, about all these claims about sunscreen being toxic for us.

6:17And so people will often point to all these active ingredients that we find in sunscreens. And there is this one ingredient in particular that I want to focus on called oxybenzone. This one people are particularly worked up about. Oxybenzone, okay. What is it actually doing in the sunscreen? Why is it there to begin with? So it's one of the ingredients that's there to literally help filter out the sun. Right, the UV rays. Right, and why are people worried about it? Yeah, so some of these worries about oxybenzone

6:48go back years, even decades. So for example, I want to tell you about this one study that came out in 2001 that looked at rats and oxybenzone. So in this study, scientists took a bunch of young female rats and exposed them to the chemical. And what they found was that it made their uteruses grow bigger and not in a good way. So this suggested that chemicals like oxybenzone were acting like estrogen

7:19or essentially hormone disruptors. Oh. This really freaked people out. It's been a very widely cited study. Yeah, yeah, I'll bet. But of course it's just, you know, rat. I mean... Yeah, it's not just that it's just in a rat. There's a couple other things that were going on that don't mimic how we as humans use sunscreen. For example, they made the rats eat the sunscreen chemicals. They basically spiked their rat chow with it.

7:49Uh-huh. I was going to ask, did they put it on their fur? But so they were eating the chemicals. That's not how we do it. And then how much of the stuff were they getting in their bodies? Is it at all related to what I might get if I absorb it through my skin? That's the next point. They gave them a lot of it. So I talked about this with Dr. Brandon Adler from Keck Medicine of the University of Southern California. And he told me that it would take a long time to get this level of exposure that the rats did.

8:22Looking at humans, it was estimated that it would take anywhere between about 35 and 277 years of use of oxybenzone-containing sunscreen. Oh my gosh. Anywhere between 35 and 277 years. And the shortest scenario would require applying sunscreen to absolutely every part of our bodies. Right. So this is a classic case of the dose makes the poison.

8:52And Brandon's basically saying these were unrealistic levels of these chemicals. Even for me, avid sunscreen user, I wouldn't be getting this much sunscreen into my system in such a short space of time. Right? Exactly. Yeah. Yeah. Okay. And it's a study in rats. So do we have anything in people that's more realistic that can help us understand if these chemicals are dangerous? Right. Yeah. So to get to the bottom of this, I want to tell you about these couple of FDA studies that came out right before the pandemic.

9:23And they did what are called maximum usage trials where they bring people into the lab and over multiple days they slather sunscreen like all over their bodies. Sounds fun. It's like my dream. Here's Brandon. So sunscreen was applied to 75% of the body surface area. If you look at a chart of what that means, that is a lot of your body. That's essentially everywhere besides maybe your bikini zone. So how many weeks

9:53were they getting that sunscreen on for? Four or five days total in the lab. And then what did the researchers do next? So then they measured their blood throughout that study but also 21 days afterward. And they looked to see like how much of this chemical was showing up in the blood. And we did see oxybenzone there and it was in a high enough level that it passed this FDA threshold. And this is something that people online really love to point out. Now, it's very easy

10:25for this to lead to headlines, right? Sunscreens are absorbed into the body and then you very, very quickly get words like toxic and dangerous to get thrown out. I mean, yeah, it doesn't sound great. That's the, yeah, that our body is absorbing these and 21 days later they're found in our blood at all. I don't love. I know, it's kind of icky. And then at some increased threshold level,

10:58obviously, our scientist friend doesn't sound concerned. Oh, so like those FDA studies, that threshold was very like misleading. People kind of took that and ran with it and said like, hey, look, sunscreen is toxic. Yeah, yeah. But the threshold in those studies didn't actually suggest danger at all. In fact, the FDA concluded that study, quote, these findings do not indicate that individuals should refrain from the use of sunscreen, end quote. So if they were

11:29at very high levels, toxic, dangerous levels, what would you start to see? Yeah, so I found the systematic review of around 30 studies and they looked at like studies that kind of trying to find out like does oxybenzone actually affect our hormone levels? Okay. And what they concluded was that there's no clear evidence in the literature that oxybenzone actually harms us. Uh-huh. So it looks like at the doses that most people are getting their sunscreen at,

12:01we don't need to worry here. Exactly. Yeah. And what about the coral reef?

Chemicals and coral reefs

12:08People are very worried about the coral reef. Your sunscreen is killing the coral reef. Oxybenzone, which has been known to bleach our coral reef. It can damage coral reefs and wildlife, so you don't want to do that. So do I need to worry about that? Yeah. So oxybenzone is one of those chemicals that has been banned in places like Hawaii. Uh-huh. Because they're worried about their coral reefs. Yeah, they're worried about their coral and the bleaching. Uh-huh. When you take a closer look at these studies, the science is also a bit more nuanced. Like, scientists

12:38would bring young coral into the lab and then expose them to these sunscreen chemicals and find that it was toxic to their DNA. It caused coral bleaching. But when you look in a real-world setting and actually measure the amount of this stuff that's floating around in the ocean, we don't see it in nearly as high scary levels. Mm-hmm. It's all about the dose. Uh-huh. Yes. It's all about the dose. Whether you're talking about the coral, whether you're talking about the people. Mm-hmm.

13:08We know beyond a shadow of a doubt that the primary cause of coral bleaching is climate change, right? That's been shown now. It has been suggested by more realistic and moderate studies that sunscreen exposure, especially oxybenzone, may add what they call insult to injury. But it's certainly not the primary cause of the decimation of coral reefs that we've been seeing. Guys, it's climate change. But despite that, all of these studies did lead to some changes.

13:40A bunch of manufacturers have taken out this chemical oxybenzone from their sunscreens anyway because people just weren't buying them from the shelf anymore. Oh, okay. Because consumers didn't want it. And so what are they putting in the sunscreen these days? Should we be worried about that? Well, here's the thing. People are worried about all the other ingredients that come in sunscreens. There's a bunch of other chemicals that also showed up in these same studies. But the story is pretty much the same. Like, they do get into our blood,

14:10but we have no evidence that they hurt us. And as someone who has dug into the research, Brandon isn't worried about them. I have chemical sunscreens on my face right now. I was outside this morning in the early morning sun and I applied chemical sunscreens. So I personally do not believe that there is a significant risk with routine use of these ingredients. Hmm. And he said chemical sunscreen. On all sunscreens,

14:42chemical sunscreens? So they can break down into like two major pools. There's chemical sunscreens and then there's mineral sunscreens. Oh, yes. I have heard this. Sounds like marketing fluff. No, mineral sunscreens are legit. Are they really? What is the difference? It sounds like it's all a chemical. But mineral sounds, you know, like a nicer chemical you'd get at a spa. Yeah. I mean, it's a little,

15:13to get a bit nerdier, the chemical sunscreens have organic molecules in them and the mineral sunscreens have inorganic ones these are things like zinc oxide. So by organic chemical just because I don't want the audience thinking that means it doesn't have pesticides in it, you mean it's carbon based? Yeah. Mm-hmm. Okay. And then inorganic, like zinc oxide, no carbon in there. And are they better? So the people who are maybe still freaked out about the fact that chemical sunscreens

15:44get into your blood at all, mineral sunscreens are the other option because they more so like sit on the surface of your skin and they don't go down into your blood in the same way as those chemical sunscreen ingredients. Uh-huh. However, they are more likely to give you a white cast. They leave a white cast on your skin.

DIY sunscreens and new ingredients

16:04Uh-huh. And then these DIY sunscreens that people are making, I mean, do they work? Yeah, I was curious about that too. So I asked Brandon. And what I'm seeing more and more is that whenever an ingredient or a product gets called toxic, the next sentence is let me sell you a non-toxic alternative. And this is when we get into homemade recipes for sunscreens

16:34that we're finding on the internet. People are turning to making their own sunscreens with zinc oxide and beef tallow. How are they getting their zinc oxide from sunscreen? Is this like the Simpsons? You made a spoon out of a bigger spoon? I gotta process that for a second. You made a spoon out of a bigger spoon?

16:54I guess they're buying the mineral. You know, like they, but it's like you took sunscreen and then made a different sunscreen out of it. Like you just added beef tallow to the sunscreen you bought at the store. I actually found one study that looked into these kind of online recipes. What they did was find 15 recipes from online and they whipped them up in the lab and then tested them out. Ooh, and what did they find? It turns out a few of them didn't even have anything in them that could act as a sunscreen and then the rest

17:25were less than an SPF of 6. Uh-huh, which is unlikely to help you. It's not gonna help you, yeah. When people have looked at how effective these homemade sunscreens are, they really aren't at all. So don't DIY your sunscreen. No shockers there. For those of us in the U.S., there is some sunscreen news. There was this chemical sunscreen ingredient that was recently approved. It's called bemotrisenol and it's the first sunscreen ingredient

17:56that we've gotten approved in like 20 years. Wow. Good job. Good work, guys. It's been in Australia for a while, this ingredient, and Europe, but why are people getting excited about it? Yeah, so I talked to Brandon about it and he says it has a lot going for it. I would say the U.S. is just barely catching up. So bemotrisenol does a great job being a true broad-spectrum sunscreen ingredient. It is very stable and mixable with other

18:26sunscreen ingredients, which is a real plus here. And in addition, bemotrisenol is a large molecule that is not easily absorbed into the skin or into the body. Mm-hmm. So, okay, so it doesn't get absorbed too much, so it's kind of like the mineral sunscreens. What are some other benefits? So, it's very stable, so the sun, like, you know how you have to reapply sunscreen every couple hours, but this means that it's a little bit more stable. It's probably going to protect you for a little longer,

18:57so kind of guarantee your safety a bit more. And then, it also, if you've heard about, like, European and Asian sunscreens being, like, really nice and easy to sort of, like, rub into your skin, just, like, applies really nicely and finely, this kind of, why are you laughing? Because it's, it just feels like this classic, like, the grass is greener. Over there, they have the best sunscreens in the world. It's true, though. Have you tried Korean sunscreen?

19:27I guess I've traveled. I just shove it on my face. I don't think too deeply. Yeah. I mean, maybe you've had the good one all along, though. It's true. It's true. It's been 20 years and we've been without it. Okay. It's true. So, it rubs in, it rubs in nicer. Yeah. And then when you have studies look to see if it gets into your blood? Yeah. There's been studies and it does not get into the blood in the same way. It sits on top more like the mineral sunscreens. Oh, awesome. So, will you be buying that one now?

19:58Yeah, for sure. I'm going to keep an eye out for it. Mm-hmm. Okay. So, here's where we're at so far. Your sunscreen is not toxic, although it does have chemicals in it that, depending on the kind of sunscreen you get, may turn up in your blood and in super high doses that can cause trouble, particularly in rats or in rat studies. But most of us, all of us, are probably not

20:29getting those high scary doses.

20:32So, so far, I'm sticking with my sunscreen regime, Michelle. Okay, sounds good. But what's coming up after the break? After the break, we're going to be looking at vitamin D. Ooh, yes, because that could change things for me. And I have always wondered, am I blocking out too much of the sun's rays? Am I lowering my vitamin D levels too much? Yeah, with your sunscreen, right? Yeah.

21:03Yeah. And while we're heading into the break, if you have a friend who's afraid of sunscreen, maybe send them this episode.

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Vitamin D and sun exposure

22:35Today on the show, we're talking all about sunscreen. Should you stop wearing it? Next up, vitamin D. We know it's important. Is sunscreen the reason that your vitamin D levels are too low? Michelle Dang, producer at Science Versus, tell us the science. Yeah, so let's start with why vitamin D is so important. It's like this middle manager that helps calcium get absorbed into our gut and we need calcium to keep our bones strong, right? So, a really bad

23:06vitamin D deficiency actually can make your bones start to become soft and even break more often. and this can manifest as a disease called rickets in kids or osteomalacia in adults. So, I talked about this with Professor Rachel Neal from QIMR Berghofer Medical Research Institute in Australia and she was like, yeah, you really don't want to go through this. So, certainly being really badly vitamin D deficient, that's worrying

23:36and that needs to be corrected rapidly. Yeah, I mean, vitamin D deficiency has also been linked to a bunch of chronic diseases, right? Yeah, we think it might play a role in the immune system and there's a bunch of studies linking it with things like having worse COVID, worse cancer outcomes, multiple sclerosis. Yeah, so super important. So, is wearing sunscreen a risk factor here? Yeah, so, you know, we get some vitamin D from our food but most of it we get from the sun. And so, how exactly

24:07does that happen? Does the sun stimulate vitamin D in us? Yeah, so it's super cool and it's one of the only vitamins that our body can actually make and it happens from the sun which is just crazy. So, what happens is that the rays from the sun hit our skin cells and inside our skin cells there's this chemical that's a cholesterol and when the UV rays hit that chemical it changes shape

24:38a couple of times from the energy and then that molecule goes on to become vitamin D. It leaves the skin goes into our blood and then here's Rachel to tell you about the rest. It gets carried in our bloodstream to the liver and then that molecule gets carried to the kidneys and to other cells to become the active form of vitamin D so it can do what it needs to do. Okay, so how much sunlight do we need to get enough vitamin D in our lives?

25:10Yeah, so it can depend on several different things like where you live, the time of the day, the time of the season but just for example it can be really fast. Mm-hmm. Rachel told me if you went out in the middle of a summer day in Brisbane on the east coast of Australia. It takes about five minutes wearing shorts and a t-shirt. Wow, that's really quick. It's not long, yeah? Now that's if you have pale skin like Rachel and another important part here is if you have

25:40darker skin it's going to take longer, about 20 minutes under the same conditions. Uh-huh, to get enough vitamin D for your daily needs. Mm-hmm. And you know, that's in Australia. There are probably across different places in the world if you're looking at summer and you're looking at midday you see a similar thing. Okay. Winter, it's going to take longer. 6 a.m. it's going to take longer. But it's not huge amounts of time so does sunscreen affect this

26:11or do you kind of just get enough sun even if you put sunscreen on to get your vitamin D needs? It's a valid question because the same exact UV ray that we need to create vitamin D it's called UVB rays is the same exact one that sunscreen is designed to block. Mm-hmm. So let me tell you about a study that we have which was done by Rachel and her team where they wanted to test this all out does sunscreen affect your vitamin D levels?

26:43And so they did this study in Australia and they gathered 600 people for it who said that they don't wear sunscreen that often about two or less times a week and then they split them into two different groups one of them they told like just carry on as usual do what you're doing the other group was told to put on sunscreen in the morning every time it was forecasted that the sun was going to be strong enough to harm their skin

27:14okay and for the sunscreen nerds out there that's when the UV index is at UV 3 or higher

Testing sunscreen and vitamin D

27:21yes you got it mm-hmm okay and that's pretty much every day in Australia except for the winter uh-huh so on these days the sunscreen group were told to wear SPF 50 sunscreen and they had to wear it everywhere that they had skin exposed and to make sure that they actually used it when they were supposed to Rachel and her team bugged them a lot about it we sent them text message reminders every week saying the UV index is going to get to 3 this week make sure you use your sunscreen and we phoned them

27:52and we made sure that they were doing it as much as they possibly could and how long did this go on for a whole year a year yeah it was a whole year what an amazing study okay so what did they find so um they measured the vitamin D levels um at the beginning of the study after the summer and after the winter mm-hmm and what they found was that throughout the summer it looked like on average vitamin D levels were fine levels were going up in both groups

28:22mm-hmm and they didn't see vitamin D deficiencies across the board in the sunscreen group oh so in summer the groups had the same amount of vitamin D it wasn't just that the sunscreen group wasn't deficient they actually were all making an equal number on average of vitamin D well actually to clarify the people wearing sunscreen nearly every day actually made a little bit less vitamin D than the control group

28:53got it and so you know like people wearing sunscreen were still making they were still making vitamin D because we know that sunscreen is not like a perfect blocker it still lets in some of those UV rays what happened in winter yeah so they kept following these people and by the end of winter they did notice something very interesting and there was about a 35% increased risk of being vitamin D deficient at the end of winter in the sunscreen group than in the control group

29:25ooh I mean they were really wearing a lot of sunscreen there but what does Rachel make of this I was really surprised by the results mmm mmm mmm okay now everyone in the study made less vitamin D in the winter which is what you'd expect yeah but the fact that the sunscreen group made less vitamin D throughout the summer is what made the difference here

29:55because another interesting thing is that our bodies can actually hold on to vitamin D in our fat tissues and release it slowly over several months I asked Rachel was it that the daily sunscreen wearers built up less of the storage like a store of vitamin D that would last them through the winter through the winter correct yeah so the store ended up lower at the end of summer which meant that as they went down in winter they ended up lower at the end of

30:26winter and if you imagine that that happened year after year after year so you you've used sunscreen for a year you're lower in winter you go up less in summer because you're using sunscreen every day so now your store is even lower than it was you end up even lower at the end of the following winter so with these repeated yearly cycles you can imagine that if you did this all the time you could end up quite deficient so I guess now we play the game of risks and benefits Michelle

30:56so okay wearing a lot of sunscreen does put you at a risk of vitamin D deficiency but we're not doing this for fun we're doing this to protect our skin from cancer effects of aging so is that still real because some people online say even

Sunscreen and skin cancer risk

31:21that's a lie so yeah here's the concern with skin cancer those UV rays from the sun are coming down hitting our skin getting through those cells to the DNA and causing a mutation in that DNA and then again we're talking about doses repeated exposure to the sun can help those mutations accumulate over time yes yes this is what we've known for a long time so why is and then the obvious next step would be if you can wear sunscreen block those

31:53UV rays reduce the chance of DNA damage you can protect your skin that's the line from the health authorities Michelle but what is is it true when we look at the new science so when we get into the real world studies it gets a little bit messy the kind where they gather a bunch of people ask them about their lifestyle and what they do whether they wear sunscreen and then later look to see you know do they have skin cancer

32:24yeah and some of these studies find that some people who wear more sunscreen get less skin cancer yeah what you'd expect but you know not every study finds that people really like to point to this one study that was done in 2023 out of the UK okay where it looked at the health data of over 400,000 people and it found that people who wear more sunscreen more often are more likely to get skin cancer wait so that people

32:55who wore more sunscreen were more likely to get skin cancer yes that sounds big study 400,000 people it sounds damning for the sunscreen propagandists out there like me but it is making me wonder could it be that the people who were wearing more sunscreen were actually out in the sun more often and they

33:26were badly applying sunscreen and that's why they had more skin cancer yeah you are right on track the authors of this study came out to say that people online are misinterpreting this study and even though they found a link what's likely really happening here is that people who wear more sunscreen are more likely to go outside and be outside in the sun but maybe under this false security because maybe they're not wearing enough of it

33:56or not reapplying and that kind of thing so do we have any better studies that can help us yeah so Wendy we actually have one RCT randomized controlled trial and this one happened in Australia it looked at 1600 people and similar to Rachel's study it split these people into two different groups one was given sunscreen and told to wear it every day and the other was told to carry on as usual do whatever they want okay and Wendy they followed

34:27these people for over a decade wow this is an amazing study this is exactly what we need 1600 people followed for a decade because skin cancers can take a while to develop so what did they find did the sunscreen group get less cancer yeah so they looked to see who in the study got skin cancer and there are three main types of skin cancer there's squamous cell carcinoma basal cell carcinoma and then

34:58there's the scary one melanoma which is more likely to spread and kill you and what the RCT found was that the sunscreen worked pretty well for that one type of skin cancer squamous cell carcinoma it basically dropped cases 40% between the two groups uh-huh uh-huh but what about melanoma yeah so when it came to melanoma the evidence was actually less clear um there was 11 people who got melanoma in the sunscreen group

35:29versus 22 in the control group that's a 50% lower risk michelle yeah but it actually didn't come out to statistically significant probably because the cases were just too low okay interesting it does seem like then sunscreen's still protecting you from skin cancer that story is still true even if it's not your silver bullet right and yeah like the dermatologists i spoke to they're like hey if we were to redo this study um looking

35:59at melanoma which is the scarier one maybe the the data would be even stronger today because back then they were using spf-16 and now we're using spf-30 spf-50 and in that study did it matter about your skin tone if you have darker skin or lighter skin does that affect your risk here yeah so here's the thing with that study most of the people in it were white which brings us to this other idea where some people say that people with darker skin don't get the

36:30same benefits from sunscreen okay well we already know if you've got darker skin you're at an increased risk of vitamin d deficiency so if we're playing this risk benefit game gotta be some strong benefits here is it true that if you have darker skin you're at a lower risk of skin cancer so i talked about this with dr aday adanson who's a dermatologist from dell medical school at university of texas austin and based on a day's own experiences in the clinic like with melanoma he told me well one as

37:01a dermatologist if i just think about the people that i see right um and like i can maybe i can only may think of one or two black people that in you know doing this for 15 years having actually seen or diagnosed one right you don't see it a melanoma he's talking about melanoma specifically yes exactly if you look at the data um people of color do get melanoma a lot less than white people for example a black person's

37:32risk of getting melanoma is 30 to 40 times less than a white person and that's specifically the kind that spreads and and not only that when it does show up and and people with darker skin it's often showing up in a very particular way you know people of color that mostly get melanoma on the palms of their hands soles of the feet places that are not related to sun exposure so so all of this was very like curious today and he wanted to take a step back and

38:02understand whether sun exposure is linked to melanoma and people of color in the first place like is there a connection here at all and so he said you know what let me do a systematic review which is the top of the evidence pyramid right you you know you get all the studies looking at this and see what what comes out of it is there actually data to support UV is an important risk factor for melanoma so they got together this big review on it and he and his team wrangled up the

38:33data crunched the numbers yeah and the answer to whether or not sun exposure is linked to melanoma and people of color and to sum it up no it is not it is not in anyone that identifies as non-white not asian not hispanic not black right there is there is like the almost zero data to support

Melanin and skin tone differences

38:59that whoa and why is that is melanin is super protective for melanoma what's going on yeah so that's also really cool what's happening there no matter your skin color we all have these cells in our skin called melanocytes that make the pigment melanin and when we step outside our melanocytes start pumping out melanin in response to the sun

39:30and that's why you tan yeah over time you would you would eventually tan but before that like Ade told me that melanin actually gets packaged up and is like sent like it makes its way toward the surface of your skin I don't know if you've ever noticed a phenomena in the first you know 10-15 minutes of some people getting some sun they make it slightly you know darker that's your melanin if you have enough at least that's it moving out around the cell in order to protect the DNA from the incoming

40:00UV exposure that's like one immediate response wait so the melanin nanocytes the cells that make the melanin then the melanin is like sunscreen for your DNA like natural sunscreen for your DNA yeah so like this melanin it's directly responding to the sun it's moving up there and it's it's wanting to protect you from those UV rays and in essence

40:31protects you from the DNA damage that could cause skin cancer wow that's so cool and yeah the more the more melanin that you have in your skin the more likely it's doing a similar job to sunscreen here's a day again so it is helping you know absorb some of the harmful effects that the UV will have on the DNA and you know depending on how dark you are you know you can have

41:02sunscreen or SPF of 15 plus um equivalent at least if you're of a darker skin tone that's so cool so then does yeah so does this mean if you have a darker skin tone then wearing sunscreen is not a good idea because then you're at an increased risk of vitamin D deficiency and you don't get this skin cancer benefit I guess specifically for melanoma there are other skin cancers to worry about yeah so you're right

41:32on track like after studies like a days came out countries like Australia actually changed their guidance on sunscreen recommendation so people that are of the darkest skin types don't routinely need to wear sunscreen to prevent skin cancer they classify it by what's called the Fitzpatrick scale so there's six different skin tone types and the two darkest skin tones are not recommended to wear sunscreen for skin cancer in Australia

42:03so we'll throw that up on screen on the flip side though places like the US the American Academy of Dermatology haven't changed their guidelines and this is something that annoys a day a lot we're not science based the recommendation is not and it's also wild because we're in this era of personalized medicine right there should be personalized risk stratification related to the sun anyone saying sunscreen saves lives for

42:34personal color is lying that is a bald face bald face lie should people of color wear sunscreen then does this change the equation yeah so I asked a day and he said that you know sunscreen isn't useless like it still prevents sunburn and could have cosmetic benefits because we think that melanin better protects against UVB rays versus UVA and UVA rays are the ones that penetrate

43:04a little bit deeper into our skin and messes with things like elastin and collagen and can contribute to like an effect of aging okay and wrinkles and things like that I asked a day like does he still recommend his patients who are people of color to wear sunscreen sure I do sunscreen has a lot of important usage no matter your skin type you can sunburn right that is possible people like to use it for anti-aging

43:35but you know for listeners that might not see my image I'm a black male dermatologist and so yeah I wear sunscreen I went to the beach like a few weeks ago I had sunscreen on you know I didn't want to get burned but do I wear it daily no I don't but that's me that's my I'm a different risk say than somebody that you know looks like Pippi Longstocking and I guess

44:06if for anyone worried about a vitamin D deficiency no matter your skin tone can you just take a supplement if you still want to wear sunscreen is vitamin D supplementation okay yeah going back to Rachel Neal who we heard about with the vitamin D study I asked her like can you just take a supplement and she's like yes that's that's the easy fix to this if you're worried about it great okay now

44:36Rachel herself she doesn't look like Pippi Longstocking but she does have pretty pale skin and skin cancer is something she's very concerned about she's also had it before when I brush my teeth I put my sunscreen on every day so for me I think that's really important we know that that reduces risk of skin cancer and I've had three so I had my first skin cancer when I was 29 which you know shows how problematic the Australian sun can be and it's the same in other parts of the world as well where there's a

45:06really high UV which means that just popping outdoors is enough to cause damage all right is it time for our sunscreen summary

Practical sunscreen application tips

45:15sounds good okay so sunscreen does have chemicals in it obviously some of them can get into our blood but as far as we can tell they're not causing harm while they're there at the doses that they're there if you are worried about it though you can try mineral sunscreen which is more likely to stay on the top of your skin and not go into your blood sunscreen does increase your risk of having

45:45vitamin D deficiency which is particularly concerning if you have darker skin you're at a higher risk of that on the other hand if you have darker skin you also don't need to worry so much about melanoma and not great evidence that sunscreen can protect you from that but if you have lighter skin then sunscreen is going to protect you from skin cancer yeah you got it I think based on all of this I'm going to keep wearing my sunscreen but I'm

46:16going to start taking a vitamin D supplement okay yeah that's good all right we got a lightning round ready to go yes lightning round lightning round it's where we say some quick facts that can help you in your day we've had a lot of questions about this just the practicalities of sunscreen if you're still on team sunscreen after listening to this episode here's some tips and tricks about putting it on properly okay when should you wear it

46:47okay so if you open up your weather app you will see a section that says UV index basically telling you how strong the UV rays are that are coming through the atmosphere okay weather app here we go yeah all right so here's what I got Melbourne middle of winter low all day it's gonna be one so you actually so like you need to wear sunscreen if the UV hits three or above so today you actually don't need to wear

47:17sunscreen next question which SPF should you wear so in Australia they recommend SPF 50 plus other places recommend 30 plus however the dermatologist I spoke to said you might as well wear 50 because we know from studies that most of us are bad at putting on sunscreen and that we don't put enough of it on okay speaking of badly putting on sunscreen even though I'm mad for it I shove it on as soon as I leave the house but I

47:47hear you need to put it on 20 minutes before is that real you do yeah it's fascinating because like you actually need time for it to dry and set on your skin it will adhere a little bit better and then you're kind of like guaranteeing protection oh mm-hmm um all right do I need to wear it if I'm behind a window it's surprising like the windows block some of the rays but let's do a bit

48:18of UVA rays do you know there's a fascinating case report of a guy who was a truck driver and for decades would drive half of his face would be exposed to sun and the other half would be in the shade and you can it was published in a scientific journal because you could actually see more wrinkles on the side of his face yeah exactly yeah yeah so those UVA rays are getting through and we know that they're connected with

48:48signs of aging and also play like a little bit of role in skin cancer okay last question how much do you actually need to put on so for the whole body an easy guideline is one full shot glass of sunscreen what about just the face yeah so like let me get out my measuring tool I'm showing you a teaspoon a five milliliter teaspoon which is the same in US and Australia and the recommendation is one whole teaspoon for your face ears and neck but for

49:18your whole body you actually want seven of these thanks Michelle thanks Wendy that's science versus how many citations are in this week's episode there are 92 citations and if people want to see them in all their glory learn more about the science of sunscreen where should they go head over to our transcript that you can find in the show notes this episode was produced by Michelle Dang with help from Meryl Horne Rose Rimler and Akedi Foster Keyes we're edited by Blythe Terrell Wendy Zuckerman that's me I'm the executive producer fact checking by Erica

49:49Akiko Howard mix and sound design by Bobby Lord music written by Bobby Lord Bumi Hidaka So Wiley Emma Munger and Peter Leonard science versus is a Spotify studios original you can find us on Spotify we're also on YouTube you can like and subscribe if you liked this episode please share it with your friends helps other people know about the science in the world I'm Wendy so come in and I'll back to you next time have no fear chosen foods is here to defend your

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