Girls and boys might be more vulnerable to the negative effects of social media use at different times during their adolescence, say an international team of scientists. The researchers show that, in UK data, girls experience a negative link between social media use and life satisfaction when they are 11-13 years old and boys when they are 14-15 years old. Increased social media use again predicts lower life satisfaction at the age of 19 years. At other times the link was not statistically significant. Increased social media use again predicts lower life satisfaction at age 19 years. At other times the link was not statistically significant. In just over a decade, social media has fundamentally changed how we spend our time, share information about ourselves, and talk to others. This has led to widespread concern about its potential negative impact, both on individuals and on the wider society. Yet, even after years of research, there is still considerable uncertainty about how social media use relates to well-being.