The European Commission has accused TikTok of breaching the bloc's online content rules, alleging that its recommendation system traps users in “rabbit holes” of similar videos. Brussels claims the design can damage the mental health of children and vulnerable people. The preliminary findings leave TikTok exposed to fines worth up to 6% of parent company ByteDance's global annual turnover.

Why the algorithm is in Brussels' crosshairs

The case is the first time the Commission has found a platform's recommendation system itself to violate the Digital Services Act (DSA), the EU law that requires large online platforms to address harmful and illegal content. That makes the probe a test of whether algorithm design — not just the content a platform hosts — can breach the law in its own right. TikTok carries the DSA's enhanced obligations for very large online platforms, a designation the EU applies to services averaging more than 45 million monthly users in the bloc. A Commission official who spoke to POLITICO on condition of anonymity said regulators are now taking a closer look at how engagement-driven systems keep users hooked.

The complaint centers on TikTok's “For You” feed. According to the Commission, the more users watch or like certain videos, the more similar videos TikTok serves them. The EU argues that a steady stream of content about sadness, loneliness or body image can heighten anxiety, hurt self-esteem and worsen eating disorders. One official told POLITICO that the investigation focused on mental health because that was where the evidence was strongest.

The EU's preferred fixes — and why TikTok's fall short

TikTok has already made changes intended to soften the effect, but the EU has found those fixes ineffective. Regulators want the company to base its recommendations more on users' stated preferences than on their viewing behavior.

The Commission has also raised concerns about TikTok's “I'm not interested” button, saying it “may not be enough to change the content feed,” according to AFP. Regulators want TikTok to stop using watch time to suggest videos, make its settings easier to use and check its algorithm on a regular basis.

One official noted that the DSA requires platforms to offer a feed that does not use personal data to recommend content — an option that only 0.2% of TikTok users choose, leaving nearly the entire user base on the behavior-driven feed.

EU tech chief Henna Virkkunen said that every time users scroll or like a video, TikTok shows them more similar content, making the cycle harder to break, according to the European Commission. She added that TikTok needs to do more to protect its users, particularly children.

TikTok's fifth case and the wider EU crackdown

The EU executive has now accused TikTok — which is owned by a Chinese company — of breaking its rules for the fifth time, although it has yet to fine the platform. In February, regulators alleged the app relied on “addictive design” features and was not doing enough to protect children; TikTok called those claims “categorically false.” In July, the EU brought a further charge, saying the platform exposed children to cyberbullying and predatory behavior.

Before any penalties are handed down, TikTok can review the evidence and suggest ways to fix the problems. It would not be the company's first resolution: TikTok previously settled a DSA case concerning ad transparency by agreeing to make changes.

TikTok is not the only platform under pressure. The Commission is also examining similar issues on Meta's Facebook and Instagram, and in July it ordered Meta to reduce “addictive design.” How Meta implements that order, and whether TikTok's response satisfies the Commission, are the next developments to watch in the EU's wider scrutiny of recommendation systems.

The scrutiny mirrors legal battles in other jurisdictions. In September, TikTok paid the U.S. state of Alabama at least $100 million to stay out of court and agreed to set time limits for teenage users.