California Governor Gavin Newsom signed a law Monday that requires social media companies to display a warning to users under 18 years old about the health risks of social media platforms.

Introduced by state Assemblymember Rebecca Bauer-Kahan, AB 56 mandates that covered social media platforms display the following:

The Surgeon General has warned that while social media may have benefits for some young users, social media is associated with significant mental health harms and has not been proven safe for young users.

The display must appear when the user first opens the app, after three hours of use, and again every subsequent hour. 

The law cites a 2023 advisory on Social Media and Youth Mental Health from then-US Surgeon General Vivek H. Murthy. The advisory reported that social media has been linked with various physical and mental health concerns, like low self-esteem and eating disorders. Newsom said there have been “truly horrific and tragic examples of young people harmed by unregulated tech.” AB 56 states it is meant to warn users of such risks.

TechNet, the trade association for Meta and Google, opposed the law on free speech grounds. The law is part of a growing trend among states to require warning labels for social media platforms. The American Bar Association reported in 2024 that 42 state attorneys general endorsed the use of warning labels. California has also been pushing for broader social media regulation. Last month, the US Circuit Court for the Ninth Circuit largely upheld a California law requiring social media accounts for minors to default to private mode.

In addition to AB 56, Newsom signed several other social media laws regulating the AI chatbots, increasing penalties for distributors of pornographic deepfakes, and more. However, Newsom vetoed SB 771, which would have created liability for social media platforms whose algorithms display content that violates state civil rights laws. The governor called the bill “premature.”

AB 56 is set to take effect in January of 2027.