You Might Have Sunscreen In Your Blood — But Don't Freak Out Just Yet

Jenny Morber
You Might Have Sunscreen In Your Blood — But Don't Freak Out Just Yet

A new study finds that if you use chemical sunscreen, you might have the ingredients floating around in your blood. Should you worry? Not yet, scientists say. After all, sunburn is all kinds of bad and even if these chemicals are inside of us, we don’t know that will hurt us. Then again, we don’t really know they won’t. So, what do we know? It’s complicated, but read on.

It turns out that sunscreens were approved for over the counter use back before the FDA had a bunch of rules about making sure products like this were safe. Today we lather up on the regular, but if chemical sunscreens were new would they pass the test? That was unclear, so the FDA decided to take a look. One important question in determining what’s safe is whether the stuff on your skin gets into your body. This study says yes.

Scientists at the University of California, San Francisco got a group of 24 people (men and women, light skinned and dark skinned) and put them into four groups. Each group had someone come in and slather one kind of sunscreen on them every two hours four times a day, for four days, according to the package directions. You know, like what you would do if you spent a vacation at the beach, except if instead of the beach you were stuck in a lab. The scientists tested two sprays, a lotion, and a cream — common stuff you can find on the shelf — then looked at participants’ blood for four different chemicals.

And they found them. All of them. And not just tiny amounts; the levels were high enough to trigger further FDA review after only one day, and they built up over time. Now, everyone involved is quick to stress that YOU SHOULD NOT FREAK OUT YET. In fact, we asked one of the study scientists, David Strauss, M.D., Ph.D., four questions about these findings, and in every answer he included the words, “The fact that an ingredient is absorbed through the skin and into the body does not mean the ingredient is unsafe.” It’s important to stress that. Yes, sunscreen ingredients were found in users’ blood. But that doesn’t definitively mean those ingredients are dangerous — it just means they are there.

The Skin Cancer Foundation has also released a statement and does not seem super pleased about the fear-factor in these findings: “3.5 million Americans will be diagnosed with melanoma, SCC or basal cell carcinoma in 2019,” the statement reads. “There’s simply no justification for abandoning sun-safe behaviors.” Likely they are concerned that people will decide sunscreen is dangerous, stop using it, thus putting themselves at a higher risk for skin cancer. For good reason: Sunburns and skin cancer are definitively bad for you.

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But there is some evidence that sunscreen might not be all that great for you either. One of the chemicals found in this study, oxybenzone, has been associated with lower testosterone in people, and is a known allergen, according to Heather Patisaul, Professor of Biological Sciences at North Carolina State University. In animal studies, she says, another one called octinoxate disrupted thyroid hormone signaling and changed the animals’ behavior. And both of these chemicals are known to damage coral reefs.

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Other research suggests that chemical sunscreens might disrupt our hormones, potentially causing cancer or problems with growth, reproduction, and immune system. Sunscreen chemicals have been found in breast milk, and some seem to be toxic to human brain cells. In a study that manages to be both alarming and sad, scientists found that another sunscreen chemical builds up in developing fetal dolphins. But does that mean these chemicals could get to or harm a human fetus? We just don’t know.

In fact, there’s a lot we don’t know about sunscreen. So far the FDA’s efforts to get sunscreen manufacturers to test their own products has failed, or at least they aren’t sharing the information. Here are some things we don’t know: How sunscreen chemicals get into our bodies, if these chemicals are harmful, how much might make them harmful, if the risk changes in sun or water, if the chemicals can affect a fetus when worn by a pregnant person, if the skin of babies and children absorbs them differently, if sunscreen in kids’ blood affects them differently, or even what the optimal amount is.

Researchers say they need to do more studies and gather more information. Some experts say the kind of sunscreen that turns you a bright ghostly white might be a better choice. That kind has ingredients that the FDA says are “generally recognized as safe,” but the Skin Cancer Foundation cautions that they might not work as well.

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Patisaul, a self-proclaimed fair skinned southerner says, “If people are concerned, they can use alternative strategies for reducing sun exposure like wearing protective clothing, avoiding the sun when the UV index is high, and using mineral-based sunscreens.” In related news, do you own a wide-brimmed hat? We might just grab one or five for the summer. And a blousy shirt. And maybe a bigger beach umbrella.