Shedding light on sunscreen myths

Scientific evidence demonstrates that sunscreen is effective for combating skin damage and skin cancer. On social media though, one frequently hears a different story: that sunscreen is unnecessary, or worse still, that it poses a risk to our health, including cancer^[1].

These claims have become ingrained in the popular consciousness, so much so that many young adults today dismiss the dangers of unprotected sun exposure. A 2024 survey by the American Academy of Dermatology found that about 1 in 2 adults aged 18 to 26 were unaware of sunburn risks and roughly 1 in 3 had an inadequate knowledge of sun protection.

Inaccurate narratives claiming sunscreen is unnecessary or harmful discourage sunscreen use and place people at an increased risk of skin cancer. In this Insight article, we aim to tackle some of the most prevalent misinformation narratives about sunscreen.

The Sun is essential to life, but that doesn’t mean it can’t hurt us

Some social media posts assert that unprotected sun exposure is safe because the Sun is essential to life on Earth (examples here and here). As Kristin Cavallari, an American celebrity who said she skips sunscreen, put it, “the Sun is life-giving and nourishing”. This conception of the Sun is sometimes reinforced by a common logical fallacy known as the appeal to nature: the Sun is natural, so it’s good (example here).

But this line of reasoning is flawed, since two things can be true at once. It is correct to say that the Sun is essential to life on Earth, but there can be too much of a good thing. The same sunlight that allows plants to grow and promotes vitamin D production in humans (and many other animals) can also cause harm. That’s because sunlight contains ultraviolet (UV) radiation, which is recognized as a cancer-causing agent by the International Agency for Research on Cancer.

UV radiation can damage our DNA by directly causing chemical changes and indirectly by promoting the formation of free radicals in cells that damage DNA. Both processes cause mutations that increase the risk of cancer. While our cells have DNA repair mechanisms, these don’t work all the time, meaning some damage slips under the radar. These mutations can manifest years down the line as skin cancer.

Another closely related narrative—which is connected to the human tendency to romanticize the past—asserts that unprotected sun exposure is safe because early humans didn’t use sun protection yet were unaffected by sun damage. But drawing parallels between early humans and humans today is problematic for several reasons.

In an article for The Conversation, anthropologist Nina Jablonski acknowledged that early humans were indeed better adapted to sun exposure, but as humans shifted from a hunter-gatherer lifestyle to one of agriculture and indoor living, this adaptation ceased to be needed. The upshot is that modern humans cannot count on benefiting from the same adaptation:

“As people have moved around more and faster over longer distances in recent centuries, and spend more time indoors, their skin hasn’t caught up with their locations and lifestyles. Your levels of eumelanin probably aren’t perfectly adapted to the sun conditions where you live and so aren’t able to protect you the same way they might have your ancient ancestors.”

Moreover, while our ancient ancestors may not have developed skin cancer, “[t]his is not to say that the skin would have been undamaged by today’s standards,” Jablonski pointed out. “Dermatologists would be appalled by the leathery and wrinkled appearance of the sun-exposed skin of our ancestors.”

She reminded readers: “People may love the sun, but we’re not our ancestors. Humanity’s relationship with the sun has changed, and this means changing your behavior to save your skin.”

Dermatologist Geeta Yadav also addressed this popular misconception in an Instagram post. She highlighted that the ozone layer in the time of early humans was in a much better state than it is today, enabling it to block more UV radiation from reaching the Earth. This means that early humans didn’t receive as much UV radiation as we do today.

Secondly, the life expectancy of early humans was much shorter compared to that of humans today; most early humans did not live past their forties. This nuance matters because while skin cancer can affect people at any age, it is most commonly diagnosed in older people. For instance, the estimated number of new melanoma cases in the European Union in 2020 showed that the majority of cases were concentrated in the age group 45 and above. And the American Cancer Society states that the average age of a person diagnosed with melanoma (invasive skin cancer) is 66.

In other words, most early humans didn’t live long enough to develop skin cancer.

In summary, it is true that the Sun provides many benefits that make life on Earth possible. But claiming that this means unprotected sun exposure isn’t harmful is an extremely reductive view that fails to account for the scientific evidence demonstrating otherwise. Comparisons to ancient humans are misguided, since we are no longer adapted to sun exposure like our ancient ancestors, and we no longer live under the same conditions that they did.

No evidence that sunscreen causes vitamin D deficiency

Vitamin D is involved in many processes essential to our body, ranging from bone health to hormones to immunity. One way we obtain vitamin D is through sun exposure, as UV radiation triggers vitamin D production in skin cells.

Naturally, some are concerned that sunscreen will prevent our body from making enough of this vitamin. Studies indicating a correlation between vitamin D deficiency and certain types of cancer further compound concerns over the potential health impact of sunscreen use^[2,3].

On studies linking vitamin D and cancer…

Remember that correlation alone is not evidence of causation. Furthermore, the same correlation wasn’t observed in other forms of cancer^[4].

• Having a high vitamin D level above what is considered sufficient wasn’t associated with a protective effect for endometrial, esophageal, gastric, kidney, non-Hodgkin lymphoma, ovarian, and pancreatic cancers
• In the case of pancreatic cancer, high vitamin D levels were associated with a higher risk instead.
• A reminder not to over-generalize the results of scientific studies: just because an effect has been seen for one cancer doesn’t necessarily mean we can assume the same applies to other cancers.

The nonprofit Cancer Research UK states that “There isn’t enough convincing evidence to link low levels of vitamin D (vitamin D deficiency) to cancer. And there’s not evidence to support taking vitamin D supplements to reduce cancer risk.”

The good news is that published studies on that front have been reassuring, as they have not shown that sunscreen use leads to vitamin D deficiency.

There are a few reasons why this is the case. For one thing, sunscreen doesn’t block all UV radiation. For example, an SPF 30 sunscreen filters out about 97 percent of UV light, meaning 3 percent still gets through. An SPF50 sunscreen is marginally better, filtering out 98 percent of UV radiation. On top of that, this degree of UV filtering also assumes that someone has applied sunscreen perfectly. But most people don’t use enough sunscreen and don’t re-apply when necessary (usually two hours after the previous application).

What all of this means is that our skin can still synthesize some vitamin D from the Sun even when we’re wearing sunscreen. And we don’t need long periods under the Sun to get enough vitamin D either. The Australian charity Cancer Council states:

“When the UV Index is 3 or above (such as during summer), most people maintain adequate vitamin D levels just by spending a few minutes outdoors on most days of the week.” [emphasis added]

In addition, sun exposure is not the only way to get vitamin D; we can also get it through our diet. Oily fish, like salmon and mackerel, as well as egg yolks and red meat are good sources of vitamin D. If food alone isn’t enough, there are vitamin D supplements for people who need them.

Put simply: is vitamin D important to health? Yes. Does using sunscreen lead to vitamin D deficiency? Nothing in the scientific literature tells us this is a concern.

No evidence showing sunscreen is harmful to human health

Arguably the most frequent concern about sunscreen has to do with its use of certain chemicals that are claimed to disrupt hormones and cause cancer. Science Feedback discussed this myth about sunscreen ingredients in a previous review. This claim can be found in different languages, including Spanish and French.

Certain UV filters used in sunscreen, such as oxybenzone and octocrylene, triggered health concerns after the U.S. Food and Drug Administration discovered that these chemicals could be detected in blood after sunscreen use^[5].

Studies also found associations between the presence of these chemicals and altered levels of various hormones, including testosterone and estrogen^[6]. However, these associations alone don’t prove that changes in hormone levels were caused by sunscreen. Several factors—such as seasonality and physical activity—influence hormone levels and many studies didn’t account for these factors. It’s also unclear what the associations mean in terms of health outcomes, and conflicting results between studies add to the uncertainty.

One study that tested sunscreen chemicals in cell cultures and rats found that the chemicals acted like estrogen^[7]. However, it comes with major caveats. For one thing, the animals were exposed to sunscreen chemicals through their diet, which is not how humans use sunscreen. And other researchers pointed out that for at least one commonly used UV filter, oxybenzone, the study used very high concentrations that don’t represent the level of exposure through normal sunscreen use^[8].

In short, some studies found that sunscreen chemicals can enter the body, but studies haven’t shown that these chemicals produce harmful effects.

Some social media posts cite studies finding a correlation between sunscreen use and skin cancer as evidence that sunscreen causes cancer (examples here and here). But these posts overlook a well-known phenomenon known as the sunscreen paradox. In short, when people feel protected by sunscreen, they tend to stay longer in the sun. The problem with this is—as we explained earlier—sunscreen does not provide 100% protection from UV radiation and most people don’t use enough sunscreen and don’t reapply when needed.

The less-than-optimal use of sunscreen, combined with prolonged sun exposure, paradoxically culminates in a higher risk of skin cancer. In other words, it is not sunscreen itself that causes cancer, but the change in behavior triggered by using sunscreen that increases skin cancer risk.

Beware of recipes for homemade “sunscreen”

Some social media posts encourage people to make their own sunscreen using “natural” ingredients, providing various recipes for homemade sunscreen (examples here and here). The implication here is that “natural” ingredients are safer than the chemicals used in commercial sunscreen—a common logical fallacy known as appeal to nature.

These posts may even go as far as to assign an SPF rating to ingredients, implying an equivalence with commercially available sunscreen that display SPF ratings on their labels.

However, since homemade sunscreen isn’t subjected to testing, neither its effectiveness nor SPF rating can be established. Commercially available sunscreen, on the other hand, is tested as it needs to comply with regulations that many countries, including member states of the European Union, Australia, and the U.S., put in place to ensure sunscreen safety and effectiveness.

Cancer Council doesn’t recommend using homemade sunscreen:

“While the ingredients might be natural, most have not been tested for their ability to absorb or reflect cancer-causing UV radiation or protect against sunburn. Natural oils generally have a very low UV radiation blocking ability, insufficient to provide any sun protection.”

Conclusion

Sunscreen is an imperfect but effective tool for reducing the harmful effects of UV radiation. However, social media narratives incorrectly vilify sunscreen by employing inaccurate but emotionally appealing narratives about the health benefits of unprotected sun exposure and unsubstantiated claims about sunscreen’s harms. Scientific evidence doesn’t show that sunscreen raises the risk of cancer or other health problems—on the contrary, it is beneficial by reducing UV-induced skin damage and mitigating the risk of skin cancer.

REFERENCES

1. Marcon et al. (2026) Sunscreen is overwhelmingly promoted on TikTok, but content with misinformation exhibits proportionally high levels of audience interaction. PLoS Digital Health.
2. McCullough et al. (2019) Circulating Vitamin D and Colorectal Cancer Risk: An International Pooling Project of 17 Cohorts. Journal of the National Cancer Institute.
3. O’Brien et al. (2022) Vitamin D concentrations and breast cancer incidence among Black/African American and non-Black Hispanic/Latina women. Cancer.
4. Helzlsouer KJ. (2010) Overview of the Cohort Consortium Vitamin D Pooling Project of Rarer Cancers. American Journal of Epidemiology.
5. Matta et al. (2020) Effect of Sunscreen Application on Plasma Concentration of Sunscreen Active Ingredients. JAMA.
6. Jaskulak et al. (2025) Endocrine and Reproductive Health Considerations of Sunscreen UV Filters: Insights from a Comprehensive Review 2014–2024. Current Environmental Health Reports.
7. Schlumpf et al. (2001) In vitro and in vivo estrogenicity of UV screens. Environmental Health Perspectives.
8. Wang et al. (2011) Safety of Oxybenzone: Putting Numbers Into Perspective. JAMA Dermatology.

These materials were developed in 2026 for the Prebunking at Scale project, with support from the European Fact-Checking Standards Network.