TikTok allegedly conducted experiments in which thousands of users, including children and teenagers, were given non-functional versions of safety features they believed would protect them from unwanted or potentially harmful content, according to allegations contained in a newly unsealed New York lawsuit against the social media company.
The allegations, contained in an updated complaint filed by New York Attorney General Letitia James, raise fresh questions about TikTok's handling of safety features designed to give users greater control over the content recommended to them.
According to the lawsuit, TikTok carried out so-called "ghost" or placebo experiments involving users who attempted to activate its "Algo Refresh" feature. The tool is designed to allow users to reset the recommendations generated by TikTok's algorithm, particularly when they want to move away from content they no longer wish to see or consider potentially harmful.
The lawsuit alleges that some users were led to believe they had successfully activated the feature when, in fact, they had been placed in a test group that received a non-functional version.
As a result, their feeds did not undergo the same changes experienced by users who received the functioning version of Algo Refresh, according to the complaint.
Internal concerns over the experiments
The allegations suggest that concerns about the practice were raised inside TikTok itself.
A product manager responsible for Digital Well Being at the company reportedly questioned the use of placebo testing for Algo Refresh, warning that the practice could be misleading to users.
"This feature is about algorithm transparency and control," the employee wrote in an internal chat, according to the lawsuit.
"A placebo group completely conflicts with that."
Despite the concern, TikTok allegedly repeated the experiments on thousands of users during 2023.
The lawsuit claims the company compared people who received the actual feature with those who did not in order to assess factors including how long users remained on the platform and the effect on advertising revenue.
The allegations are part of a broader legal battle between TikTok and US states over the company's treatment of younger users and the design of its platform.
New York accuses TikTok of misleading users
James originally filed the lawsuit in 2024. The allegations concerning the experiments were included in an updated version of New York's complaint filed under seal in late August and subsequently ordered unsealed by a judge.
The case is one of more than two dozen lawsuits brought by states accusing TikTok of designing aspects of its platform to encourage addictive use among children and teenagers and of misleading consumers about the safety of its service.
Many documents in those cases have remained sealed or heavily redacted as TikTok has sought to prevent details about its internal operations from becoming public.
New York's lawsuit alleges that TikTok publicly presents safety as a priority and promotes the platform as appropriate for younger users while, internally, restricting access to certain safety features for some groups.
The complaint specifically alleges that some users who had actively sought to avoid unwanted or potentially harmful content were nevertheless prevented from accessing the tools intended to help them do so.
TikTok has rejected the allegations.
"We continuously make improvements to our platform which means that, like most companies, we regularly test new products and features to validate the experience and understand how they work in the real world," a TikTok spokesperson said in a statement.
The company has broadly denied New York's allegations in court filings and has maintained that protecting young users remains a priority.
Dispute over how Algo Refresh works
The lawsuit also accuses TikTok of misleading users about what Algo Refresh actually does.
According to the complaint, the company told users that activating the feature would reset the algorithm responsible for recommending videos to them. The lawsuit alleges that the effect was instead temporary.
TikTok's spokesperson disputed that characterization, saying the allegations misrepresent how Algo Refresh operates.
The dispute over the feature goes to the heart of the broader case: whether users, particularly young people, were given meaningful control over the content presented to them or were led to believe they had more control than they actually did.
Separate safety experiments under scrutiny
The newly unsealed sections of the lawsuit also describe another series of experiments involving TikTok's safety systems.
According to the complaint, TikTok randomly selected users and disabled certain safety features on their accounts, exposing them to potentially harmful content that those safeguards would otherwise have limited.
The allegations concerning those experiments had previously been reported by Bloomberg.
One case cited in the lawsuit involves a teenage boy in New York who was allegedly included in one of the tests and later died by suicide after being exposed to content relating to self-harm and suicide, Bloomberg reported.
Internal reviews, according to the lawsuit, found that the teenager had been exposed to an "onslaught" of material about suicide and self-harm.
The allegations do not by themselves establish that TikTok's experiments caused the teenager's death, but they form part of New York's broader argument that the company's safety practices exposed vulnerable young users to serious risks.
Legal pressure mounts on TikTok
The New York case comes as TikTok faces growing legal pressure across the United States over its impact on children and teenagers.
In September, TikTok settled the first state lawsuit that had been scheduled to go to trial, agreeing to pay Alabama up to $300 million and make changes to how its platform operates for teenagers in the state.
The continuing litigation could bring further scrutiny of TikTok's internal testing practices, recommendation algorithms and safety systems.
For state authorities, the newly unsealed allegations provide a rare glimpse into how some of those systems were tested internally. For TikTok, the cases represent a significant legal challenge to the way it develops and evaluates features on a platform used by millions of young people.
As more documents are unsealed, the central question for regulators and courts will be whether TikTok's experiments amounted to legitimate product testing or crossed the line by withholding safety protections from users who believed they had deliberately chosen to activate them.