Young adults who spend a lot of time on such sites are more likely to feel cut off from the world, according to a new study.
Researchers found that more than two hours of social media use each day doubles the chances of feeling isolated.
The study quizzed almost 1,800 adults aged 19 to 32 about their use of the 11 most popular social media sites - Facebook, YouTube, Twitter, Google Plus, Instagram, Snapchat, Reddit, Tumblr, Pinterest, Vine and LinkedIn – when the research was conducted in 2014.
People who visited the sites more than 58 times a week were found to be three times more at risk of experiencing loneliness than those who logged on fewer than nine times per week.
Lead scientist Professor Brian Primack, from the University of Pittsburgh School of Medicine, said: "We are inherently social creatures, but modern life tends to compartmentalise us instead of bringing us together.
"While it may seem that social media presents opportunities to fill that social void, I think this study suggests that it may not be the solution people were hoping for."
