Sunscreens in your blood??! That FDA study

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How to cite: Wong M. Sunscreens in your blood??! That FDA study. Lab Muffin Beauty Science. May 9, 2019. Accessed December 22, 2023.

You’ve probably seen the recent influx of articles about the new FDA sunscreen study, usually titled something like “sunscreens can make it to your bloodstream!”

The study itself is fine and good and necessary as a first step in the FDA’s new zeal for sunscreen regulation. But the more I read the coverage around it, the more annoyed I get, because it’s a perfect illustration of how terrible the media is at reporting on science. It’s just… SO BAD. (Do they pay their writers too much, or not enough? I can’t decide.)

Here’s the original study (it’s open access, so you can read the full text without any logins): Matta MK et al., Effect of sunscreen application under maximal use conditions on plasma concentration of sunscreen active ingredients: a randomized clinical trial (open access), JAMA, published online May 06, 2019. DOI: 10.1001/jama.2019.5586


Note the words “preliminary communication” and “maximal use conditions”. And then let’s have a quick look at the headlines that this inspired:

Top Coverage from Google News

mens-health sunscreen

cnn sunscreen

wired sunscreen
From Wired

So it sounds like there’s a new study that’s the first to find that sunscreens soak into blood, which is bad.

If you’re a long time reader of my blog, you’ll probably guess why I think we shouldn’t freak out:

  • Concentration matters, and unless we know what the concentration means (anything can be safe at a low enough dose) then there’s not really much need to panic.
  • The trial was done on a small group (6 subjects per sunscreen)
  • The quantities of sunscreen used are higher (around double) typical use

And this is what the authors of the study say, and what experts have said as well.

But this latest round of the media misreporting the science is even more frustrating than normal, because…

We’ve known that sunscreens absorb into the blood for over a decade

We’ve known that sunscreens applied on your skin absorb into the blood for a long, long time, from animal, skin model AND human studies. Even if we ignore the skin model and animal studies (which would already lead us to expect that they’d penetrate into blood), the human studies already show they enter the bloodstream.

These studies found sunscreens (mostly oxybenzone) in human urine. Urine forms via filtration of blood, so it’s expected that the source is from sunscreens entering the blood. The earliest study here is 1997 – so, just a fresh 22 years ago:

Even if you allow for the fact that journalists might not know that urine and blood are related, it isn’t new – some studies that found sunscreen in blood after skin application are 15 years old. They’re off having awkward sexual encounters and rebelling against their parents now.

And even if the journalists don’t know how to use Pubmed or Google Scholar to type in “sunscreen absorption” or “sunscreen blood” (which they should, since a fair few of them are specifically science reporters) – it’s in the open access editorial accompanying the study.


So what’s actually new about the study?

It’s mostly the fact that the amounts of sunscreens in blood from commercially available sunscreens have been quantified in detail, although the maximum concentration of oxybenzone isn’t that different from the 2004 Danish study. The amount of data on specific filters is pretty much non-existent (apart from oxybenzone, which exists but is a rare Pokemon), so it’s always good to have additional data, even if it’s preliminary. But this mostly serves as an impetus to get scientists to actually work out what the concentrations mean, particularly since the FDA is behind the study.

But these aren’t really as hype-worthy as “they’ve been found IN YOUR BLOOD!”, I guess.

Fearmongering sells, so screw what the scientists say

The turning of science into clickbait is especially disappointing here. Yes, consumers have a right to know where the gaps in the data are, but most of the popular media articles end with recommendations for alternative filters.

This is despite the study addressing this head on, in both the abstract and the conclusion (and again, it’s open access, so it isn’t like the reporters couldn’t see it):



The accompanying editorial says it too, plus it points out that avoiding the filters studied can also lead to negative health outcomes – something which pretty much all of the popular coverage has been advocating, or at least suggesting as a good option.


The FDA press release also states this clearly:



The worst are probably the articles I’ve seen where, to achieve “balance”, they quote a dermatologist on one side… and just some randoms off the street for the other side.

What the actual hell, My NBC 15:


Actual Good Coverage

To end on a positive note, here are some examples of good coverage you can read if you want to find out more about the study, that doesn’t do exactly what everyone has been saying not to do. A special shout-out goes to Gizmodo, with their clickable-but-not-misleading headline:


And the fact they used the study’s conclusion as their conclusion, and seem to have actually read the study (imagine that!):


Here’s a collection of opinions from experts that aren’t mangled and truncated. As someone who’s started providing journalists with quotes, and who talks to scientists and doctors who are frequently used as sources in the media – having your opinion mangled then attributed back to you is disturbing AF.

One of Australia’s public broadcasters SBS also has an article full of expert opinions.

The American Academy of Dermatologists has also released a statement on the study.

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16 thoughts on “Sunscreens in your blood??! That FDA study”

  1. Thank you for this post! Especially the links to expert opinions. I’ve seen some awful headlines about this study – science reporting in popular media can be truly terrible.

  2. Thank you for your voice of reason! I have been seeing these headlines and I think it’s seriously irresponsible. Hopefully people will see posts like yours and the actual good coverage that is out there.

  3. This is why the media annoy me so much, they take something someone’s said and twist it to suit themselves!! They do it a lot. I don’t believe most of what I read now.

  4. What was even worse about the media coverage was that the study was released on the American Academy of Dermatology’s Melanoma Awareness Day. So there were headlines stating the importance of sunscreen sitting next to headlines stating the supposed dangers. For the average consumer, that’s confusing and frankly dangerous.

    • I would LOVE to be a Big Sunscreen shill! Big Sunscreen, if you’re reading this, please pay me to do what I’m already doing 😀

  5. I always enjoy reading your breakdowns of studies, your writing is super engaging!

    By the way, on my recent AP Chem exam (college level exam for high schoolers here in the us, not sure what the aus equivalent is) there was a free response question on the solubility of urea, and i thought of you 🙂

  6. Thanks for debunking this! I’m a journalist in the U.S. and agree on the failures of the media covering science. Interestingly the university where I went to grad school had a program for medical doctors and researchers to get a master’s in journalism, in part to improve reporting on medicine/health/science.

    I had an unrelated question since you’re in Australia. I’m trying to get my hands on Finacea (azelaic acid gel 15% or a generic equivalent) and having trouble. I’ve read that it’s OTC in Australia and I see a few sites sell it online, like Do you know if that site is legitimate? Finacea is extremely expensive in the U.S. even with insurance and hard to find. It seems like many people are buying it on eBay but that seems riskier if you can even locate it.

    • Chemist Direct is legit as far as I know. We also have Azclear, and there’s The Ordinary Azelaic Acid as well which is available from UK sites like Beauty Bay 🙂

  7. Thank you once again for your scientific check of facts and bringing this to light.

    Yet more instances of fear-mongering by mainstream media. My theory is that this draws in listeners to drive high ratings so their exorbitant salaries can be justified. It can no longer be classified as journalism or news – there is no fact checking- it’s all sensationalism. I get an FDA feed so I saw the press release and being an educated chemist (although not highly educated as you are, I have a BS) – we know that the truth is often somewhere in the middle. Studies can contradict each other and it’s a matter of parameters and controls selected. You can’t always do a direct comparison.

    I will continue to use my sunscreen (I used zinc oxide and titanium dioxide because I am sensitive to many of the other ingredients) because the alternative (rapid skin aging and skin cancer) is worse to me.

  8. Hey Michelle,

    I have become a big fan of your blogs now.
    I actually spent an entire weekend reading your blogs without getting bored.
    Your use of humour along with providing scientific data, makes it very enticing it read.

    Wish you all the best.

    A fellow techie girl,

    Pallavi Kotian


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