LONDON — TikTok’s endless scroll of irresistible content, tailored for each person’s tastes by a well-honed algorithm, has helped the service become one of the world’s most popular apps.

Now European Union regulators say those same features that made TikTok so successful are likely illegal.

On Friday, the regulators released a preliminary decision that TikTok’s infinite scroll, auto-play features and recommendation algorithm amount to an “addictive design” that violated EU laws for online safety. The service poses potential harm to the “physical and mental well-being” of users, including minors and vulnerable adults, the European Commission, the 27-nation bloc’s executive branch, said in a statement.

TikTok Must Overhaul Core Features

The findings suggest TikTok must overhaul the core features that made it a global phenomenon, or risk major fines.

“TikTok needs to change the basic design of its service,” the European Commission said in a statement.

TikTok said it planned to challenge the findings “through every means available to us.”

“The commission’s preliminary findings present a categorically false and entirely meritless depiction of our platform,” the company said in a statement.

Regulators accused TikTok, owned by Chinese company ByteDance, of disregarding signs it was being used compulsively, including available data about the time that minors spend on the platform at night and the frequency that users open the app. TikTok rewards users with new content, regulators said, encouraging them to keep scrolling and putting their brains into “autopilot.”

TikTok, which has more than 200 million users in Europe, should limit infinite scroll features, create new screen time limits and change its recommendation system, the European Commission said.

No timeline was given on when authorities will make a final decision in the case. TikTok now has a chance to respond to the allegations. It faces potential fines of up to 6% of its global revenue for violations of an EU law called the Digital Services Act.

TikTok has been under EU investigation since 2024 for the “rabbit hole effect” it has on users, particularly young people. A Pew Research Center report last year found that 16% of American teenagers said they were on TikTok “almost constantly.”

The findings of European regulators are similar to allegations made in various U.S. lawsuits, which claim that features like endless feeds, automatically playing videos and personalized recommendations have led to compulsive use and caused depression, eating disorders and self-harm among young people.

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This article originally appeared in The New York Times.

By Adam Satariano
c. 2026 The New York Times Company