In the United States, TikTok is by far the most popular social media platform among teenagers It's a new milestone. While TikTok's future in the United States remains somewhat shaky, the Chinese platform is now the favorite social network among teenagers there.

The impact of social media on young people’s mental health and well-being is a growing topic of concern among parents, educators, health care professionals and regulators. And now, nearly half of US teens say social media has a mostly negative effect on people their age — and almost the same proportion say they’re cutting back on social media use.