Senators Demand Answers After TikTok Ran Suicide-Content Experiment on 15 Million Users

TikTok has until September 1 to answer 13 questions from two senators about an experiment that stripped a safety feature from 15 million American users, including a teenager who later died by suicide.

Senators Marsha Blackburn, a Tennessee Republican, and Richard Blumenthal, a Connecticut Democrat, sent a four-page letter Wednesday to TikTok CEO Shou Chew and Adam Presser, CEO of the company's U.S. business. They called the experiment "depraved" and "disgusting," according to the letter, which was reported by Fortune, the LA Times, TechCrunch, Engadget, The Record, and The Next Web.

What TikTok reportedly did

The episode traces back to a confidential 2023 TikTok document that surfaced in litigation against major social media companies and was placed under court seal, according to Fortune and the LA Times. Bloomberg Businessweek reported the document's contents earlier this month.

In December 2021, TikTok publicly announced it was building a safeguard to stop users from being fed clusters of repetitive, potentially harmful content, according to Senator Blackburn's office. What the company did not disclose, the senators say, is that it simultaneously withheld that same protection from roughly 10% of U.S. users, a control group of about 15 million people at the time, so it could measure whether the safeguard hurt engagement.

One member of that control group was Chase Nasca, a 16-year-old from Bayport, New York. According to the internal document cited by Bloomberg and confirmed across Fortune, the LA Times, and The Record, Chase was randomly placed into the test on January 25, 2022. Over the following weeks his feed filled with videos about sadness, hopelessness, loneliness, suicide, and self-harm. He died by suicide in February 2022, within a month of entering the test group.

TikTok's own internal review found Chase watched more than 7,500 videos in the final two weeks of his life. Seventy-three percent touched on themes of sadness or personal struggle, and nearly 10% violated the company's own content rules, according to The Record and Senator Blackburn's office. The document states plainly: "TikTok's filter bubble prevention strategies did not take effect on this user by design." It also describes the decision as "a delicate balance across safety and the ability to measure impact on DAU (daily active users) and core metrics."

What the senators are demanding

The letter asks for the names of every TikTok employee who knew about the experiment, an explanation for why minors were allowed into the control group, when executives first learned of the test, and an unredacted copy of the internal document, according to The Next Web. It also asks for something broader: a full list of every algorithmic experiment TikTok has run in the U.S. where it withheld, disabled, delayed, or reduced a safety feature, and how many users, including minors, were affected each time.

Blackburn and Blumenthal are the co-sponsors of the Kids Online Safety Act, which cleared the Senate Commerce Committee on August 5, according to The Record. They argue the TikTok episode is exactly the conduct their bill targets. "When signed into law, KOSA will address exactly the kind of conduct these disclosures raise: platforms designing products and algorithms to maximize addiction while children bear the consequences," the senators wrote, per The Record.

The Record also notes KOSA is unlikely to pass this session because lawmakers still disagree over whether to impose a legal duty on platforms to prevent foreseeable harm to minors. Opponents of a broad "duty of care" standard, including some free-speech and civil-liberties groups, have argued in the past that vague harm-prevention mandates could pressure platforms into over-moderating lawful content or give the FTC leverage to police speech indirectly. Supporters counter that without some enforceable duty, companies like TikTok have no legal incentive to stop running engagement experiments on kids. Neither side's argument is addressed head-on in this letter, which is focused narrowly on TikTok's specific conduct.

TikTok's response so far

TikTok has not responded to the senators' letter, according to every outlet in this batch of coverage. The company did give Bloomberg a statement for the original investigation, saying it is "deeply committed to the safety and well-being of users," especially teens, and that "our hearts break for any family that experienced a tragic loss." The company pointed to its investment in "Trust & Safety," including "robust detection systems and dedicated enforcement teams that proactively remove content that violates our Community Guidelines," per Fortune and the LA Times.

That statement doesn't address the core allegation: that TikTok knew about the safeguard's protective value and chose to withhold it from a control group specifically to measure engagement impact. No regulatory investigation or lawsuit tied specifically to this experiment has been announced. The document that exposed it remains under seal, and the senators' request for an unredacted copy is, for now, unanswered.

The Record notes the disclosure lands the same week a trial began involving Meta and four state attorneys general who accuse the company of deliberately designing addictive products for minors, a separate case but a similar underlying question about whether platforms knowingly trade child safety for engagement metrics. TikTok's deadline to respond to the senators is September 1.