Key Takeaways
- Meta’s internal Project Mercury study found users felt less anxious and socially pressured after Facebook breaks
- Company terminated the research despite early positive results for mental health
- Internal staff compared Meta’s actions to tobacco industry hiding health risks
- Major lawsuit alleges social platforms knowingly withheld evidence of harm to young users
Meta quietly shut down an internal mental health study called Project Mercury after early results showed Facebook users experienced significant improvements in well-being when they took breaks from the platform. The revelations come from newly unsealed court documents that raise serious questions about whether tech giants concealed evidence of potential mental health risks to young users.
What Was Project Mercury?
Launched in late 2019, Project Mercury was Meta’s internal initiative to study how Facebook and other platforms affected emotional well-being, information exposure, and social behavior. The company partnered with research firm Nielsen to gather comprehensive data comparing user experiences with and without platform access.
The study involved random samples of Facebook and Instagram users who voluntarily paused their activity for extended periods—up to one month in some cases. Researchers measured changes in mood, self-perception, and social patterns to provide Meta with verifiable data on the psychological impact of its products.
Results showed users who disconnected from Facebook for just seven days reported fewer feelings of loneliness, reduced social comparison, and decreased anxiety and depressive symptoms. These findings directly contradicted Meta’s expectations and suggested the platform might worsen emotional states for certain user groups.
Internal Concerns and Tobacco Comparisons
Court filings reveal significant internal concern about Project Mercury’s findings. One employee noted in internal communications: “The Nielsen study does show causal impact on social comparison,” adding an unhappy-face emoji.
Another staff member drew a stark comparison to corporate history’s most controversial cases of scientific suppression, asking: “If the results are bad and we don’t publish and they leak, is it going to look like tobacco companies doing research and knowing cigs were bad and then keeping that info to themselves?”
Despite these concerns, Meta terminated Project Mercury without proceeding to further research phases or sharing findings publicly. The lawsuit alleges Meta’s public testimony about teen safety directly contradicted what internal research suggested.
Meta’s Defense and Response
Meta spokesperson Andy Stone strongly rejected the allegations, stating the company halted Project Mercury due to methodological flaws rather than fear of results. “The full record will show that for over a decade, we have listened to parents, researched issues that matter most, and made real changes to protect teens,” Stone said.
He argued the study merely showed that “people who believed using Facebook was bad for them felt better when they stopped using it”—matching patterns seen in earlier public “deactivation studies.” Stone maintained this “doesn’t show anything about the actual effect of using the platform.”
Broader Lawsuit Allegations
The sweeping US lawsuit targets multiple social platforms—Meta, TikTok, Snap, and Google’s YouTube—accusing them of knowingly expanding risks that disproportionately affected young users while publicly insisting their products were safe.
Specific allegations against Meta include claims that the company:
- Engineered youth safety features that rarely functioned as intended
- Required 17 detection attempts before removing users engaged in sex-trafficking behavior
- Delayed critical measures to restrict contact between minors and potential predators
- Prioritized engagement metrics over safety despite recognizing harmful content exposure
The filings reference a 2021 exchange where Mark Zuckerberg stated protecting children online wasn’t his main focus, noting he was “more focused on like building the metaverse.”
Industry-Wide Implications
The multidistrict litigation represents one of the most expansive legal challenges against social media in US history. If courts determine companies suppressed research and misled the public, it could transform industry practices and regulatory expectations.
Project Mercury serves as key evidence that Meta had clear warning signs about potential harms but failed to act. The upcoming hearing scheduled for January 26, 2026 will determine whether additional contested documents become public.
Consequences for Meta could extend beyond financial penalties to include court-mandated disclosure requirements for internal safety research and potential restructuring of research divisions. The tobacco industry comparisons highlighted in internal communications may significantly influence how judges and regulators view Meta’s responsibility to disclose harm-related evidence.
