The report by Dr. Vivek Murthy cited a “profound risk of harm” to adolescent mental health and urged families to set limits and governments to set tougher standards for use.The nation’s top health official issued an extraordinary public warning on Tuesday about the risks of social media to young people, urging a push to fully understand the possible “harm to the mental health and well-being of children and adolescents.”In a 19-page advisory, the United States surgeon general, Dr. Vivek Murthy, noted that the effects of social media on adolescent mental health were not fully understood, and that social media can be beneficial to some users. Nonetheless, he wrote, “There are ample indicators that social media can also have a profound risk of harm to the mental health and well-being of children and adolescents.”The report included practical recommendations to help families guide children’s social media use. It recommended that families keep mealtimes and in-person gatherings free of devices to help build social bonds and promote conversation. It suggested creating a “family media plan” to set expectations for social media use, including boundaries around content and keeping personal information private.Dr. Murthy also called on tech companies to enforce minimum age limits and to create default settings for children with high safety and privacy standards. And he urged the government to create age-appropriate health and safety standards for technology platforms.Adolescents “are not just smaller adults,” Dr. Murthy said in an interview on Monday. “They’re in a different phase of development, and they’re in a critical phase of brain development.”The report, effectively elevating long-simmering concerns around social media in the national conversation, came as state and federal lawmakers, many of them raised in an era when social media barely existed or didn’t exist at all, have been struggling with how to set limits on its use.Montana’s governor recently signed a bill banning TikTok from operating in the state, prompting the Chinese-owned app to file a lawsuit and young TikTok users to lament what one called a “kick in the face.” In March, Utah became the first state to prohibit social media services from allowing users under 18 to have accounts without the explicit consent of a parent or guardian. That law could dramatically curtail young people’s access to apps like Instagram and Facebook.Survey results from Pew Research have found that up to 95 percent of teens reported using at least one social media platform, while more than one-third said they used social media “almost constantly.” As social media use has risen, so have self-reports and clinical diagnoses among adolescents of anxiety and depression, along with emergency room visits for self-harm and suicidal ideation.The report could help encourage further research to understand whether these two trends are related. It joins a growing number of calls for action around adolescents and social media. Earlier this month, the American Psychological Association issued its first-ever social media guidance, recommending that parents closely monitor teens’ usage and that tech companies reconsider features like endless scrolling and the “like” button.A large body of research has emerged in recent years on the potential connection between social media use and soaring rates of distress among adolescents. But the results have been consistent only in their nuance and complexity.An analysis published last year, examining research from 2019 to 2021 on social media use and mental health, found that “most reviews interpreted the associations between social media use and mental health as ‘weak’ or ‘inconsistent,’ whereas a few qualified the same associations as ‘substantial’ and ‘deleterious.’”At their clearest, the data indicate that social media can have both a positive and negative impact on the well-being of young people, and that heavy use of social media — and screen time generally — appears to displace activities like sleep and exercise that are considered vital to developing brains.On the positive side, social media can help many young people by giving them a forum to connect with others, find community and express themselves.At the same time, the surgeon general’s advisory noted, social media platforms brim with “extreme, inappropriate and harmful content,” including content that “can normalize” self-harm, eating disorders and other self-destructive behavior. Cyberbullying is rampant. Moreover, social media spaces can be fraught for young people especially, the advisory added: “In early adolescence, when identities and sense of self-worth are forming, brain development is especially susceptible to social pressures, peer opinions and peer comparison.”The advisory noted that technology companies have a vested interest in keeping users online, and that they use tactics that entice people to engage in addictive-like behaviors. “Our children have become unknowing participants in a decades-long experiment,” the advisory states.A spokesperson for Meta, the owner of Instagram and Facebook, said that the advisory included recommendations that “are reasonable and, in large part, Meta has already implemented.” Those measures include automatically making the accounts of people under 16 private when they join Instagram and limiting the types of content teens can see on the app.TikTok did not immediately respond to requests for comment on Tuesday afternoon.The advisory did not provide guidance on what a healthy use of social media might look like, nor did it condemn social-media use for all young people. Rather, it concluded, “We do not yet have enough evidence to determine if social media is sufficiently safe for children and adolescents.”The surgeon general’s position lacks any real power beyond its potential as a bully pulpit, and Dr. Murthy’s advisory does not carry the force of law or policy. It was intended, the report said, to call Americans’ attention to “an urgent public health issue” and to make recommendations for how it should be addressed.Similar reports from past surgeons general helped to shift the national conversation around smoking in the 1960s, drew attention to H.I.V. and AIDS in the 1980s and declared in the early 2000s that obesity had become a nationwide epidemic. Dr. Murthy has declared gun violence to be an epidemic and has decried what he has called a “public health crisis of loneliness, isolation, and the lack of connection in our country.”In the interview on Monday, Dr. Murthy acknowledged that the lack of clarity around social media was a heavy burden for users and families to bear.“That’s a lot to ask of parents, to take a new technology that’s rapidly evolving and that fundamentally changes how kids perceive themselves,” Dr. Murthy said. “So we’ve got to do what we do in other areas where we have product safety issues, which is to set in place safety standards that parents can rely on, that are actually enforced.”Remy Tumin