We'll see if he holds out...
It's extremely hard as a parent.
Younger adolescent girls are extremely vulnerable. But this stuff is very hard to lock down and manage. There are no good tools for managing it. The parental controls apps are leaky and crappy. Schools issue (and require!) devices, so even if you can lock your kids device, there's always alternate paths. And as a parent you are easily sidelined and ignored when you try to talk about it and bring up concerns.
Worst problems have been Tumblr and Pinterest, BTW, not Instagram. Both are full of eating disorder and self-harm content. Instagram is at least somewhat moderated. (Reddit and Twitter are also really bad, though less used by teens that I have seen.)
Go right back to being depressed again as soon as she got access to Instagram.
Repeat every three or so months until she moved out. After wasting a couple years of her life she finally got off social media all together and is doing much better.
Her much younger sister is 13 wants social media. It’s a hard no. She complained to her older sister. Older sister was extremely firm on saying to stay off it.