More likely than not, much of the science news you get throughout the day comes from scrolling through Facebook, with posts nestled between the zillionth photo of your best friend’s baby shoot and yet another cat video.

The problem: Not all of those “science” posts are science, and now that Facebook is deprioritizing content from publishers in favor of those from friends and family on your newsfeed, the opportunity for stories that don’t quite count as science to go viral has magnified.

On Wednesday morning, the Pew Research Center published a report after studying the top 30 Facebook science pages—with between 3 million to 44 million followers each in 2017—that suggests the science posts people see on social media are predominantly “news you can use” types or, more worryingly, ads.

In other words, a lot of what’s categorized as “science” as you scroll through Facebook might not be science at all.

Pew’s report suggests—perhaps unsurprisingly—that publishers attempt to sexify the science of studies in an attempt to make them clickbait. The group studied six months worth of posts from Facebook’s top 15 most popular Facebook science accounts, along with 15 other accounts of noteworthy people who are science-tangent, such as astrophysicist Neil deGrasse Tyson.

The study followed these posts—6,582 of them, to be exact—for the first six months of 2017. The researchers found that not only did tens of millions of people follow these Facebook science accounts, but that nearly one-third of users saw Facebook as their primary source of science news.

So what makes the majority of science news here? It might make sense to put “news” in quotes here; the analysis showed that traditional STEM topics were not as popular (only four of the 30 pages met that criteria), with most pages devoted to science instead looking more toward nutrition, animals, health, and astronomy. Not that those fields aren’t science, but that these topics are often tangentially touched is potentially troublesome.

And Facebook has fast seen an increase in not only volume of posts (up 115 percent from 37,000 posts in 2014 to about 79,000 in 2017) but also interactivity, with thousands upon thousands of comments flowing out from stories posted from everything on keto diets to the newest climate change study. What’s encouraged this massive uptick isn’t necessarily a demand for quality of news so much as the fact that aggregation has proven to help fuel traffic.

You might think: What’s wrong with people getting their aggregated science news via Facebook? After all, it’s been a tough few days for the company beleaguered by accusations that its data was harvested by Cambridge Analytica to disclose 50 million profiles in an effort help elect Donald Trump. And Facebook appeals to a demographic that skews more toward the middle-aged, less technologically agile, and less scientifically literate, which might make exposing this demographic to science news seemingly advantageous.

The problem is that Facebook science stories use four particular frames. One is “new discoveries,” dominated by space, physics, and hard science sites like NASA. Another popular frame is “news you can use,” where pop psychology site Psychology Today has found a foothold. The third frame is using posts as promotion, of which Animal Planet has become the strongest. And the last frame of reference for science stories is explainer journalism, of which a myriad of sites are competing for dominance, between MythBusters, Science Channel, and BBC Earth, and National Geographic.

There are a few things to extrapolate from these points. First, science news is a surprisingly sparse landscape. Science is a broad subject, and while singular views and posts devoted to discoveries in a focused way might make for a more streamlined user experience, posts are often haphazard and sometimes have nothing to do with science at all, Pew reports.

Second, you might think that getting access from top scientific thinkers and pop-culture icons might help drive serious science coverage and conversation. Indeed, astrophysicists like Tyson, Michio Kaku, and the late Stephen Hawking are the leading pages followed by Facebook users. But little of their content is original, and in fact, much of it is either generated from other sources or might not have anything to do with specific scientific discoveries at all.

That trend is made worse by groups like Smart Is the New Sexy, whose links were found to be “far afield from science topics.” That, in fact, illustrates a huge problem with Facebook “science” posts: For many of them with health or nutrition bents, advertising and promotions can sometimes form a dominant majority of content. On pages that frame their subject matter as “news you can use,” this is especially troubling: Places like Daily Health Tips derive 96 percent of their content from ads, and mindbodygreen’s content is 69 percent promotional. Even publications—like Psychology Today and Health—are guilty of using this framing around promotional posts, with 67 percent and 56 percent of their content respectively structured around promotion.

And this report, despite the fact that it addresses information from last year, is actually already dated. Early in 2018, Facebook announced it would prioritize content shared by friends and families over news publishers. While that certainly brings the original element of connecting with loved ones to bear, it makes it easier for stories that have somehow gotten misinterpreted (take last week’s viral—but very wrong—story on astronaut Scott Kelly’s DNA getting altered by 7 percent, which would have changed him from human to another species).

From a science journalism perspective, this is worrisome. If the science news you are getting is a thinly veiled ad, for example, it means the science “news” you are receiving is actually not at all science, but rather fiction. It also means that if you slant a particular direction politically, that can affect your science intake, which means “fake news” is more likely to disseminate and conspiracy theories are encouraged to mushroom. The normal fact-checking processes of publications ensure that science journalism is as factual as possible, but if information is spreading through posts that parade as science and are actually not, it makes it easier for snake-oil treatments to spread, causing danger among susceptible people. When scientists with huge social followings like Tyson or Bill Nye posted, it was more likely than not self-promotional, which means that not only are these respected voices in science often not disseminating information but they’re promoting only their point of view.

Not everything is dark. User engagement has spiked in the past year, potentially because of the Trump administration’s handling of scientific topics for policy—abortion, health care, climate change, and more. What makes this analysis of Facebook science news interesting is the fact that science funding has seen a spike up in reads and interactivity. “Posts related to science funding were typically tied to discussion of President Donald Trump’s first proposed budget in early 2017 and the potential changes for science funding,” the report notes, suggesting that political activity and interest made for a more engaged audience.

But the fact remains that Facebook is a sloppy way to understand science and gain new knowledge of the world around us, and the social media site’s new algorithm will make things worse.