Sunscreens in your blood??! That FDA study

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

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:

• Hayden CG, Roberts MS & Benson HA, Systemic absorption of sunscreen after topical application, Lancet 1997, 350, 863-4. DOI: 10.1016/S0140-6736(05)62032-6
• Gustavsson Gonzalez H, Farbrot A & Larkö O, Percutaneous absorption of benzophenone-3, a common component of topical sunscreens, Clin Exp Dermatol. 2002, 27, 691-4. DOI: 10.1046/j.1365-2230.2002.01095.x
• Gonzalez H et al., Percutaneous absorption of the sunscreen benzophenone-3 after repeated whole-body applications, with and without ultraviolet irradiation, Br J Dermatol. 2006, 154, 337-40. DOI: 10.1111/j.1365-2133.2005.07007.x
• Balaguer A, Chisvert A, Salvador A., Sequential-injection determination of traces of disodium phenyl dibenzimidazole tetrasulphonate in urine from users of sunscreens by on-line solid-phase extraction coupled with a fluorimetric detector, J Pharm Biomed Anal. 2006, 40, 922-7. DOI: 10.1016/j.jpba.2005.07.055
• Vidal L et al., Sensitive determination of free benzophenone-3 in human urine samples based on an ionic liquid as extractant phase in single-drop microextraction prior to liquid chromatography analysis, J Chromatogr A. 2007, 1174, 95-103. DOI: 10.1016/j.chroma.2007.07.077
• Zamoiski RD et al., Self-reported sunscreen use and urinary benzophenone-3 concentrations in the United States: NHANES 2003-2006 and 2009-2012, Environ Res. 2015, 142, 563-7. DOI: 10.1016/j.envres.2015.08.006.

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.

• Janjua NR et al., Systemic absorption of the sunscreens benzophenone-3, octyl-methoxycinnamate, and 3-(4-methyl-benzylidene) camphor after whole-body topical application and reproductive hormone levels in humans (open access), J Invest Dermatol. 2004, 123, 57-61. DOI: 10.1111/j.0022-202X.2004.22725.x
• Sarveiya V, Risk S & Benson HA, Liquid chromatographic assay for common sunscreen agents: application to in vivo assessment of skin penetration and systemic absorption in human volunteers, J Chromatogr B Analyt Technol Biomed Life Sci. 2004, 803, 225-31. DOI: 10.1016/j.jchromb.2003.12.022
• Calafat AM et al., Concentrations of the sunscreen agent benzophenone-3 in residents of the United States: National Health and Nutrition Examination Survey 2003-2004 (open access), Environ Health Perspect. 2008, 116, 893-7. DOI: 10.1289/ehp.11269

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.

Sunscreens in your blood??! That FDA study syndicated from Lab Muffin Beauty Science
May 9, 2019 at 07:39AM