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I've probably been the top sunscreen mythbuster online for the last decade, so I have thoughts! It's super cool that sunscreen misinfo is being formally studied! Big props to the authors for recognising this problem. But there's misinfo in the paper, and IMO the main claims aren't well-supported…

CLAIM 1 "Overall, the dominant narrative on TikTok promotes sunscreen use" "Our findings indicate that [sunscreen misinformation] constitutes a small portion of the most viewed videos" They estimate only 1.5% of highly viewed sunscreen TikToks state it causes harm.

I don't think 1.5% passes a sniff test for what's seen on TikTok. Quick example: CBC News showed this TikTok screenshot when they covered this study… 3 out of the 4 top videos that came up when searching "sunscreen" suggest chemical sunscreens are toxic - pretty far from 1.5%.

I think the inaccurate estimate comes from issues with the methodology: ISSUE 1 Videos were found using sunscreen-related hashtags. Hashtags have declined in use since ~2022, especially on TikTok - the algo is very good, so hashtags probably don't reflect what people are seeing.

ISSUE 2 This is more subtle - I'd guess only TikTok creators who do sponsorships are really aware of it: The view count used in the study included boosted views. "Boosting" is when a brand pays $$$ for a video to get more views from a target audience (location, age, gender, interests etc).

Brands often boost videos they paid creators to make (ads), plus their own posts. I didn't realise this was an issue until I saw the SI… Of the top 10 videos in their dataset: 6 = clearly disclosed ads 2 = posts from brands 1 = likely undisclosed ad Only 1 was likely organic (regular) content.

i.e. 8 or 9 out of the top 10 posts were boosted. This is because only the top video from each creator was included in the analysis. It's almost impossible for a creator's top video to be a clearly disclosed ad without boosting. Sponsored posts almost always get low engagement and low reach.

"Boosted" ad views are not the same as regular views. * People swipe away clearly labelled ads quickly without registering them. * Boosted ads aren't matched to users via the platform's algorithm, so they're inherently less likely to engage the user.

e.g. Here's some of my own data Average watch time: Boosted sponsored post = 1.4 & 3.6 sec Unboosted sponsored post = 8.2 & 11.3 sec Unboosted organic content = 14.9 to 30.2 sec Views per like/comment indicate views needed to "earn" an interaction - a measure of engagement.

My normal sponsored post view count at the time was ~23.5K. This means roughly 99.7% of the views on my boosted videos were "inorganic" - paid to be shown to more people, and clearly labelled that way!

Sure, boosted videos technically got lots of views… but are they really part of the platform's "dominant narrative"? Would the "dominant narrative" on YouTube be supportive of BetterHelp, or NordVPN, or KFC, or whatever ads you get in your region? I personally don't think so.

TikTok doesn't seem to think so either - they count boosted views as less when you sort by "popular"... (Note that this means TikTok has the data! They could share it with researchers!)

CLAIM 2 "Health misinformation about sunscreen attracts disproportionately high audience engagement" I categorised the top 44 videos in the dataset (representing 40% of views in the analysis). Of these, only 7-15 were likely unboosted. You can see the huge difference in engagement!

I also did a quick pass over the rest to mark the ones I thought were likely boosted. Boosted views were likely 38.5-49.5% of the total views used in the analysis - a decent confounder?

Again, my own data shows how much less engaging boosted content is - by up to 160 times. You can also see the difference in engagement in the top 10 viewed videos in the study's dataset.

So while IMO sunscreen misinformation probably does get more engagement, I don't think this data is good evidence for it. I think it's just finding that clearly disclosed paid advertising gets less engagement than the organic content people came to the platform to see. Not exactly surprising!

Perceived institutional endorsement is IME very important for the spread and impact of sunscreen misinfo - authority bias is powerful! I've seen many people cite intros of peer-reviewed papers as "gold-standard science". "Minerals reflect" is the origin of many sticky myths repeated by derms.

IME, sunscreen misinfo is often underestimated because most people believe some of it, including many experts (dermatologists, chemists…). Sunscreen science is interdisciplinary - it's difficult to spot. I rarely see an article about sunscreen misinfo that doesn't contain some.

I recently spoke at the Science Misinfo Symposium - later, some social media researchers told me they weren't aware of some conventions mentioned in my talk. IMO low-hanging fruit for getting better data about social media would be to get input from content creators - many would be happy to help!