For many of us, the messaging about sunscreen has been clear for much of our lives, or at least the past several decades.

The sun has dried much hardier things than you, so imagine what it can do to your skin. Needless drying.. burning...

If you're not getting the protection of a sunscreen and a moisturizer, guess what you could be doing to your skin.

When the sun is intense, do what dermatologists recommend. Get out of the sun. Get into the Shade. Shade SPF 15...

Wear it to protect yourself from getting sunburned and to reduce your risk of skin cancer. But lately, some of what we've been hearing about sunscreen has been a little confusing and sometimes scary.

I'm not going to wear sunscreen this summer, and neither should you.

It's absolutely toxic, made up of chemicals that are meant to be put inside your car and not on your body.

Since sunscreen came out, the rise of skin cancer has only gone up, up, and up...

Everyone tries to tell you that the sun is bad for you to wear sunscreen to protect yourself. It's B.S..

So in this week's episode, as we're still feeling the summer sun, we're going to sort through it all to give you what you need to make informed choices about how to protect yourself. We're going to dig into the connection between sun exposure and skin cancer. What the science tells us about the role sunscreen can play, and where the research stands on the ingredients in sunscreen.

I have my sunscreen next to my toothbrush, and I just put it on at the same time as I brush my teeth.

I'm Meg Tirrell, CNN medical correspondent, and this is Chasing Life Spotlight: Sunscreen.

There are good reasons people might have questions about sunscreen because of big headlines over the past couple of years. Most recently, you may have heard about a scare in 2021 over contamination with a cancer causing chemical called benzene, found in multiple popular spray sunscreen brands that led to major brands like Neutrogena, Aveeno, Coppertone and Banana Boat issuing recalls. But benzene isn't supposed to be in sunscreens.

So for this episode, we're going to talk about the things that are. There have been environmental concerns with some sunscreen ingredients, and the FDA is looking into the human health effects of certain chemicals in sunscreens as well. But before we dive into all of that, we wanted to understand why sunscreen matters so much from a health standpoint. And to do that, we went to the belly of the beast, the place with the highest skin cancer rates on Earth.

That's not a title we are happy about holding.

This is Dr. Rachel Neale.

I'm a principal research fellow at the QIMR Berghofer, a medical research institute in Brisbane, Australia.

Brisbane is on the east coast of Australia.

In what we call a subtropical climate zone. So it's warm pretty much all year round. Rainy in summer, drier in winter. And lots of outdoors activities. Very, very, very high risk of skin cancer, where I live, it's because we've got really high UV radiation. The intensity of the UV radiation where we live is particularly high. And there are lots of us here who've got skin type like mine, fair skin. A lots of us came here from Scotland and Ireland and places, when we really just didn't evolve to be living in a climate where the UV radiation is so high.

Doctor Neale has been studying skin cancer for about 30 years.

In fact, since 1993, when I did my PhD on the skin cancer study, that was the first trial to really show that sunscreen is very effective at reducing rates of skin cancer. And then I've just maintained an interest in skin cancer over the subsequent post PhD years.

In Australia, health authorities say at least two out of three people will get skin cancer at some point during their lifetime. In the US, it's about 1 in 5.

Tell us about what causes skin cancer. That link between being out in the sun and getting skin cancer.

Skin cancer is caused by exposing the cells in the skin to UV radiation, and particularly UVB radiation. So UV radiation comes in different flavors, so to speak. So the those most harmful rays cause skin cancer by causing mutations in the DNA in our cells. So if you get one it's generally not a big problem. But what happens if that mutation occurs in a gene that's really important for DNA repair for example. So our cells are not so good at DNA repair. And then we get another mutation. And then we potentially get another mutation. And then eventually we tip our cells over into forming into a skin cancer.

Can you tell us a little bit about the different kinds of skin cancers?

'So there are three main types of skin cancer. The one that's most dangerous is melanoma. And people do die from melanoma every year because it can spread beyond the skin. So if it's not picked up early enough, then by the time it's diagnosed, it can have spread to other organs in the body. And we've got new treatments for it now. So it's not so much as big a death sentence as it was. And then we've got these other types of skin cancer, which we used to call non-melanoma skin cancer, but we don't so much anymore because we don't want to call us something by what it's not, rather than what it is. So these are squamous cell carcinoma and basal cell carcinoma. And collectively we call them keratinocytes cancers because they arise from a type of cell called keratinocytes in the skin.

As Dr. Neale explains it, basal cell carcinoma, or BCC, is the most common. BCC doesn't tend to spread to other organs in the body and kill people, but it can really invade locally, she says. Squamous cell carcinoma or SCC, can spread and cause people to lose their lives.

About two in three Australians are going to have a BCC or an SCC, but predominantly BCC in their lifetime.

Are those peeling sunburns the ones that are you really got to worry about? Or is really any sun exposure potentially dangerous?

There's no doubt that having those sunburns, and particularly those sunburns that we got in childhood, do definitely increase risk of being diagnosed with skin cancer later in life, and particularly of being diagnosed with melanoma.

So those nasty burns, are definitely associated, but lifetime exposure as well. So particularly for SCC, but also for some types of melanoma, it does appear that it's that cumulative lifetime exposure. It's just going about our day to day activities that we are exposing our skin to a dose of UV radiation. And particularly if we've set ourselves up early in life with some of those early life mutations. And then we, you know, give it another dose of sunlight, then yes, we definitely tip ourselves over into getting skin cancers.

So with this growing understanding that it's not just about avoiding a bad burn on a beach day, but trying to protect our skin daily from UV rays, our use of sunscreen has started to change. Part of that goes back to studies like the one Dr. Neale worked on as a PhD student.

We knew that sunburns are bad for our skin. We knew that sunscreen could prevent sunburn, and so we began promoting protecting our skin from the sun, including using sunscreens. Before, we had hard evidence about the fact that sunscreen does reduce the incidence of skin cancer. But then in the early 90s, my PhD supervisor launched an amazing study where 1600 people who lived about an hour north of where I am now in a coastal region, half of them were randomly assigned to use sunscreen every single day. Just rain, hail or shine, no matter what they were doing. And the other half were just asked to do whatever they would normally do in terms of sunscreen application, which was not much. Actually, most of those people weren't using much sunscreen, and what we found was a marked reduction in the risk of squamous cell carcinoma and melanoma. So those results were published in 1999, and it was about 20 years later that we actually changed the recommendations in Australia to now formally recommend that people should apply sunscreen routinely on all days when the UV index is forecast to get to three or more. So we're advising people just make it as routine as brushing their teeth on those, those days where I leave that all year round that the UV index, UV index is just a measure of the intensity of the burning sun exposure. So when the UV index is not going to get to above three, we're suggesting that sunscreen is not needed, but on those days where it's going to get to three, we're advising that it just becomes part of the normal daily routine.

Has sunscreen changed very much over the decades?

Well, yes. I mean, we're we've got a much higher concentration of sunscreen. Now, interestingly, that study that showed that sunscreen reduces the risk of skin cancer that was using a sunscreen with a sun protection factor, an SPF of about 16, and even using that quite low SPF sunscreen, there was a reduction in skin cancer. Whereas now, well, we recommend using a 30 plus, actually. But a lot of people are using a 50 plus, which just blocks out more of the harmful UV rays. But actually a lower SPF sunscreen does still do a pretty good job, provided it's on the skin and you're putting enough of it on.

And so I know there are multiple kinds of sunscreen. There's chemical sunscreens and there's mineral sunscreens. Are these sort of physical, some people call them blocking sunscreens. Are there major differences in how those work?

We use broad spectrum sunscreens, and pretty much sunscreens are formulated to have different ingredients to make sure we get protection across the entire range. But they work differently in that they the physical blockers. So the titanium and zinc sunscreens, they sit on top of the skin basically, and form a barrier, whereas the chemical sunscreens, they sort of bind to the top surface of the skin and turn the UV radiation into heat and then disperse from the body's heat.

'So these so-called chemical sunscreens, that's what the FDA is now taking a closer look at the ingredients in them. After the break, we talk with a scientist who's been researching some of the ingredients in question.

When sunscreen is used as it's actually intended, we take up a lot more of it into our bloodstream than was ever really known before.

We'll be right back.

It shouldn't come as a surprise that something that you put on your skin passes through your skin.

Doctor Laura Vandenberg is a professor of environmental health sciences at the University of Massachusetts Amherst.

I'm trained in the study of hormones and how hormones play a role in the development of the body. So I first became interested in some of the ingredients in sunscreens because of their ability to affect the way that hormones work in the body.

The FDA is interested in this, too. They told us that when sunscreens were first evaluated back in the 1970s, two major things were different. First, that scientists didn't know that things put on the skin could be absorbed through the skin. That's something that's now widely understood, and it's even a way some medicines are delivered, like nicotine or hormone patches. And also, as we talked about with Dr. Neale, the way we use sunscreen has changed a lot too. We don't just dab a little on our nose before spending the whole day on the beach. We slather it on, and we use a daily as part of our skincare routine in many instances.

So over the last five years, the agency has made some changes to which active ingredients in sunscreens it considers generally recognized as safe and effective or GRASE for short. 16 active ingredients were previously on the GRASE list. Two, aminobenzoic acid or faba and trolamine salicylate were removed because of safety concerns. Two others, zinc oxide and titanium dioxide, which are used in mineral sunscreens, stayed on the list. But the FDA said the remaining 12 ingredients need more data before they can still be considered safe and effective by the FDA. And as a result, they were removed from the GRASE list. Dr. Vandenberg says this is all based on recent studies about proper sunscreen usage.

If you use it as intended, which is what would make it effective, there's a lot more of it that's ending up in our bloodstream than we realized. And the concern is that we don't know enough about its safety. So what the FDA has asked the manufacturers of these chemicals, and really these products to do is to do studies where the sunscreen would be used as intended, and then see how much of these chemicals end up in the bloodstream. Because the FDA has standards for how much of these chemicals should be in our blood, and currently they can't meet that standard of both safe and effective.

Now, it's worth mentioning that sunscreens with the 12 ingredients in question are still available. And according to the FDA and every expert we talked to, people can still use these sunscreens while more research is done. The safe and effective designations for zinc and titanium dioxide, the ingredients in mineral sunscreens, are based on the fact that they sit on top of the skin. As Dr. Neale told us. And just because the other 12 ingredients penetrate the skin, that doesn't inherently make them unsafe.

You know, I spent a lot of my career criticizing the way that regulatory agencies make decisions. I think we should actually give them credit when they can acknowledge that what they thought before there isn't enough evidence to support it. In this case, I think that really what they're doing is signaling that there isn't enough evidence to say that they're dangerous. But that's not the standard that we should have for products that we're putting all over our body, for products we're putting on the bodies of children. We want to know that they're safe, but we also want to know that they're doing the job because the job of sunscreens is really critical.

Well, on that note, what does the body of research that we have so far, including your own work, suggest about that.

So I think that for the most part these chemicals are effective when they're used as intended. But here's the problem. Most of us put on the amount of sunscreen that we feel is sort of enough so I can't see it. Right. You know, you rub it into your skin, but that's not actually the way that they're intended to be used to protect us. So a colleague of mine would say three full fingers of sunscreen just for your face.

So, like this covers fingers with sunscreen, and that's just for your face.

Oh, my gosh, if I told you how much I use this morning, it was like my fingertip on my whole face.

That's right.

Like the back of my neck and my hands.

That's right. So. So we're not putting on enough. And really, we should be putting on that amount on your face every 90 minutes if you're outside.

So it's very expensive.

Yes, absolutely. You know, I've recently traveled and I bought some sunscreen because there wasn't sunblock available, which is what I often try to use, which uses minerals instead of chemicals. I bought sunscreen and it's quite expensive. And in a couple days you should use up the bottle. So if you have sunscreen that's expiring under your sink at home, number one, throw it out. But number two, you weren't using it enough when you were using that product.

A few mind boggling revelations right there. Most of us probably aren't using the recommended amount of sunscreen to get the protection that we think we are. The guidance from dermatologists is to cover 2 or 3 finger lengths with a line of sunscreen just for your face and neck alone, and for your whole body. They recommend about an ounce, which is almost enough to fill a shot glass. I also learned, much to my chagrin, that we shouldn't store sunscreen in hot places like my minivan because it can make the chemicals break down faster and cause it to not work as well. So that gets to the effective part of generally regarded as safe and effective. But what about safety?

So the chemical that I've been studying in my lab is oxybenzone or benzophenone 3. And up until, I don't know, 6 or 7 years ago. We knew very little about oxybenzone and what it would do in the body. There's just a couple of research groups that have focused on studying the effects of oxybenzone, either in cells, in culture, in the lab, or in research animals. And what those studies are now showing is that this is a chemical that can mimic estrogen in the body. It can also block the actions of androgens. So there's some evidence also that oxybenzone can alter thyroid hormone function. And to think about what the roles of those hormones play during our lives as an adult, something that affects my hormone levels is worrisome. As a baby or a fetus or someone who's going through puberty, disruptions to hormones can lead to life altering changes, increased risk for disease. And those diseases might not show up for decades in a human, but an increased risk for disease. That's evidence from cells, sometimes human cells, sometimes animal cells, and also from studies in animals. There's also increasing evidence from human populations. And I think that this is really important, because some of the critiques of the FDA's actions have come from scientists that are saying, well, we haven't ever seen anything in human populations to suggest that these these chemicals cause harm. And that's not really true when we measure how much of these chemicals are being released from the body, excreted from the body and urine, and then compare people and their risk of different conditions. There are studies that show that exposures to oxybenzone are associated with increased, neurodevelopment problems in children and increased metabolic problems in children, and also increased risk of thyroid hormone issues. So does that mean that we can say definitively that a chemical like oxybenzone causes those effects in people? No, because we're not purposefully exposing some people to oxybenzone and then comparing them to a group of people who aren't exposed ever to oxybenzone. Those people don't exist.

Some sunscreen makers have already started to remove oxybenzone from their products, not because of human health concerns, but because of environmental ones. Hawaii and Key West, Florida, for example, have banned the sale of sunscreens with the ingredients oxybenzone and octinoxate because of potential links to coral bleaching. But what about the other chemicals that have come under review? What are the next steps for those?

So from the perspective of endocrine disruption. So these chemicals that affect our hormones in our body, I think there's at least four on the list that there's some evidence that they also are likely to be endocrine disruptors. I don't know that that is going to tip the scales of the FDA's decision making. I really think that the FDA is going to make its decisions based on those standard of use studies where you're supposed to apply them, apply them as their intended, and then they'll see how much gets uptake in into the blood. I am hopeful, though, that the market itself is what's responding right. So just as some attention about oxybenzone and its effects on people and the environment has led to moving the market away from its use in these products. I'm hoping that the others, as we learn more about them, companies will continue to do, the responsible thing and move towards, safer alternatives.

We asked the FDA about when it expects to see the safety data it's asked the industry for. We spoke with Dr. Theresa Michele. She's the agency's director of the Office of Nonprescription Drugs, which regulates sunscreen. Dr. Michele said they first asked the industry for the data in 2019 and again in 2021, but she said she didn't have a specific timeframe for when they'd have it all.

'We also asked the Personal Care Products Council -- that's a trade group that represents sunscreen makers. They told us they'd already submitted, quote, human dermal studies to the agency. (Dermal meaning skin.) One of the holdups may be around the kinds of studies the FDA's asking for. Dr. Michele told us that in addition to looking at how much of a chemical gets absorbed through the skin and whether it causes allergic reactions or rashes, the agency also has more complicated questions. They want to know whether certain chemicals could cause cancer or have developmental or reproductive effects. For that, she said, they rely on animal testing. The Personal Care Products Council said it had been asking the FDA to, quote, modernize and accept new non-animal tests to demonstrate safety of sunscreens to allow the U.S. to innovate and stay competitive in the global market. And that gets us to a question we often hear about sunscreens and the rest of the world. Do other countries have better options than the U.S. and why?

There certainly are ingredients that are approved for use either in Asian countries or in the European Union that are not yet being used in the United States. There's a couple of reasons for that. One is there's a little bit of a fear that if companies did all of the testing that's required by the FDA, that people would be up in arms about that in some other places. Let me explain what I mean. In the U.S. currently, there's a requirement that ingredients that are used in sunscreens or other drugs, because sunscreen is regulated as a drug here, that you have to do testing on animals. And in the European Union. They don't test cosmetics, which is what they consider sunscreen to be. They don't test on animals. I think that's a little bit of a red herring, because those chemicals are already being used in Europe. So to satisfy our own requirements for safety is something that those companies can and should do.

So countries in Europe and other places do have more sunscreen options than we do in the U.S. Some argue those options are better, and that the U.S. is keeping the bar too high for new sunscreens to hit the market here. At the same time, Dr. Vandenberg says the FDA's scrutiny is a good thing. This is a fight that's even captured attention from Congress across both sides of the aisle. So this is not likely the end of the story.

When we come back. New research out of Australia raises a question that flies in the face of what we've been hearing for 40 years. Do all of us really need sunscreen all the time?

The sun does have benefits, particularly vitamin D production.

We'll be right back.

We've spent a lot of time examining the risks that come with sun exposure, but Dr. Neale has also been looking into the benefits it can have as well, and whether it's possible to find a healthy balance.

The sun does have benefits, particularly vitamin D production. So that's the best known benefit of those UV rays. But if it was just about vitamin D, we could just say to everybody, don't worry about it. Just protect your skin and take a supplement. And indeed, that probably is the best message for people like you and I with very fair skin. But for people who don't have our really fair skin types, it actually is probably reasonable to get a small dose of sun exposure. And I mean a short dose on most days of the week in enough to maintain vitamin D levels. And that's under the assumption that doing that will deliver some of the other benefits.

Those other benefits, she says, may include modulating our immune system in a positive way. Although she said research on that is still underway. And because it's not solid data yet, people at the highest risk should still lather on the sunscreen.

So how do you know where you fall on the risk spectrum? Well, the guidelines from Dr. Neale and a team of researchers placed people into three groups low, medium and high risk based on skin tone and personal risk factors like a family history of melanoma. If you're taking medicines that suppress your immune system or you've got lots of moles on your skin. Dr. Neale acknowledges these new guidelines are controversial. And here in the US, the American Academy of Dermatology tells us they don't have different guidance for people with different skin tones. They emphasize how important it is for everyone across the board to take precautions to avoid exposure to UV rays.

There is some concern that we will undo four decades of messaging around protecting the skin from the sun. So we will like our cancer councils who are charged with delivering public health messaging, will still focus very much on the protection message, but through clinical avenues and enabling people to go and get individualized recommendations. The plan will be that people can sort of make some decisions for themselves.

So in that spirit, taking all of what we've just heard into consideration, the question is how do we each assess the risks and benefits of sunscreen use, what type and how often do apply it for ourselves? We asked the doctors what they do.

I think it's very tricky because the properties of the chemical sunscreens make them much more pleasant to use. The physical blockers tend to be a bit thicker, and they can form a bit of a white veil on the skin. So from a from a just usability perspective, I think the chemical sunscreens are nicer to use. And certainly I use a chemical sunscreen every day. Clothing works really well. It works better than sunscreen anyway. Cover as much of the body and clothing. Wear a wetsuit if you're if you're out snorkeling on a reef. And I only put sunscreen on the little bits of you that that you can't cover by clothing. I think we forget that clothes actually work really well. So I think from a aquatic ecosystem perspective, probably the mineral sunscreens are better, but I don't think we have really concrete evidence, like the concerns have risen from experimental studies using higher concentrations of sunscreen. And I don't think we have enough data about how high those concentrations actually are in those ecosystems and how much harm they're going to do. So it's really just taking a precautionary approach.

Dr. Vandenberg has a different take.

Based on what I know and in my own practice, lean towards a physical sunscreen and then use correctly, right. More than you think you need and reapplying every 90 minutes.

But if, if you can't find that or it's expensive or you just hate the feeling of it, you'd say use a chemical sunscreen versus nothing.

Correct. Absolutely. Yes. Skin cancer is very real.

Well, it's really helpful to hear how you think through it, because one of the things we've been hearing about a lot is that there is some movement among especially younger people, young adults, who think sunscreen is worse than sun exposure without sunscreen because of concerns about chemicals.

I, I study these chemicals. I am worried that we have allowed endocrine disruptors to be in sunscreen products, but they're also in literally everything around us. And removing that one product as a way to protect yourself from endocrine disruptors, and yet increasing your risk in this other area is not a sound thing to do. I love though, the activist approach, because what we really need to do is demand safer products, and we can demand that from the companies that we give our dollars to, because I want them to constantly reevaluate whether this is the best thing for me and change the ingredients when something better and safer comes along. And we need to demand that of our regulatory agencies. And in some cases, their hands are tied. The regulation, as it's written, doesn't allow them to reevaluate the safety of chemicals. That's that's more the case in like food and food packaging than it is in something that's considered drugs, like sunscreen in the US is considered a drug. We need to demand, then, that our legislators write laws that allow us to reevaluate the safety of chemicals. Because when we know that something's harmful, it shouldn't take an act of Congress to remove that chemical one at a time. I think we often put the burden on the wrong people. So, you know, a mom who's shopping and knows that they're going to be going to the beach this weekend, should not have to be a chemist, should not have to be a public health professional, should not have to be a dermatologist in order to make the best decisions for her and for her family.

And finally, what does the FDA say about all this? Dr. Theresa Michele says the best sunscreen is the one you feel comfortable using, making sure you've got one labeled broad spectrum, meaning it protects against both UVA and UVB rays and has an SPF of 15 or higher. And of course, don't forget staying in the shade, covering up with a hat and sun protective clothing, avoiding being out when the sun is strongest. Those all help too.

For me, I am not yet 40 and I've already had a couple brushes with basal cell carcinoma, so I have been pretty cautious. I've been a faithful mineral sunscreen user for a while, but actually the conversations we had with both Dr. Neale and Dr. Vandenberg made me feel better about reaching for other sunscreens, if those are what's available. And that's why we put this episode together, not to tell you what to do, but in the hopes that you'll feel better informed to decide for yourself.

Oh, and one more thing. We didn't talk much about sunscreen and signs of skin aging, but if you're in a higher risk group and the doctors haven't already convinced you.

Sun is an absolute major cause of looking older.

Another good reason to stay safe in the sun.

Chasing Life is a production of CNN audio. Our podcast is produced by Eryn Mathewson, Jennifer Lai, Grace Walker, and Jesse Remedios. Our senior producer and showrunner is Felicia Patinkin. Andrea Kane is our medical writer, and Dan Dzula is our technical director. And the executive producer of CNN audio is Steve Licktieg with support from Jamus Andrest, Jon Dianora, Haley Thomas, Alex Manasseri, Robert Mathers, Leini Steinhart, Nichole Pesaru, and Lisa Nanemrow. Special thanks to Ben Tinker, Amanda Sealy and Nadia Kounang of CNN Health and Katie Hinman.