Some teens are spending a quarter of their lives on social media. These are the sites sucking up their time.

That figure is even higher for some individual teen segments. For example, 17-year-olds spend 5.8 hours per day using social-media apps — or just under a quarter of the average day, every day — versus 4.1 hours for 13-year-olds. And teen girls in general spend about an hour more scrolling on social media than boys do, clocking an average 5.3 hours daily, according to the poll, versus 4.4 hours for boys.

The survey was done this past summer as part of a larger one by Gallup that looked at family and adolescent health. Data was collected from 6,643 parents and 1,591 adolescents who were the children of those parents, according to Gallup.

So which sites are sucking up most of your teenager’s time? It’s actually not TikTok. The Gallup survey also looked at which social-media apps were the most popular. And YouTube took the top spot, accounting for 1.9 hours of daily teen viewing, although TikTok was close behind at 1.5 hours.

And when it comes to measuring how much time teens spend on social media versus doing their homework, guess which wins out? It should come as little surprise that scrolling beats studying, as 76.7% of teenagers spend two or more hours per day on social media, according to Gallup’s data, but just 29.1% said they spend that much time doing homework.

Some parents are clearly not wild about their kids spending all those hours on social media. According to Gallup, one in four parents (25%) strongly agree on the idea of restricting screen time for children ages 3 to 19.

The survey, whose release was accompanied by a research brief from Gallup and the Institute for Family Studies, a conservative-leaning think tank, found that mental-health issues increased among teens who spent greater amounts of time on the social-media apps. Specifically, those who spent five or more hours daily were more likely to experience sadness or even have suicidal thoughts than those who spent less time.

“These findings can guide parents, clinicians, and public health officials about the appropriate use of social media apps, and their regulation by parents, schools, and other institutions that interact with youth populations,” the Institute for Family Studies said on its website.