The EU has told TikTok it must change its "addictive design" or face heavy fines, after it found the video sharing platform had breached its online safety rules.

It follows an investigation which began in February 2024 into the Chinese-owned app by the European Commission.

In its preliminary findings, the Commission said TikTok did not "adequately assess" how features like autoplay could harm the wellbeing of its users, including children, and said it failed to implement measures to mitigate the risks.

A TikTok spokesperson told the BBC the findings presented a "categorically false and entirely meritless depiction of our platform" and it planned to challenge them.

The platform has been invited to respond to the EU's findings. Depending on the outcome of this step, the Commission could fine TikTok up to 6% of its total global annual turnover - estimated to be in the tens of billions.

EU tech chief Henna Virkkunen told reporters if TikTok wanted to avoid being fined, it would have to "change the design of their service in Europe".

The Commission gave several suggestions for actions the platform could take, including implementing "screen time breaks" when people are using it at night and changing its algorithms, which feed users personalised content.

It also suggested TikTok disable so-called "infinite scroll", which allows people to quickly cycle through millions of videos on the platform.

"The Digital Services Act makes platforms responsible for the effects they can have on their users," Virkkunen said.

"In Europe, we enforce our legislation to protect our children and our citizens online."

Professor Sonia Livingstone at the London School of Economics said while TikTok had introduced some tools to improve the online safety of its users, it was not enough to comply with the guidelines set down by the EU.

"Young people are calling for such changes," she said.

"They are frustrated that the platform does not prioritise their wellbeing over profit."

And social media expert Matt Navarra said while the use of the word addictive was "often abused" in these debates, the Commission's findings seemed to be rooted in "true behavioural science".

He added it marked a "seismic shift" in the way in which regulators were looking at social media platforms.

"This seems to be the first time a major regulator has said that the design is the problem," he said.

"It's no longer about just toxic content, it's about toxic design."

It is not the first time the EU has looked into the workings of big tech firms or threatened them with fines.

In December 2024 it began a separate investigation into TikTok over alleged foreign interference during the Romanian presidential elections.

It has also launched an inquiry in January into Elon Musk's X over concerns its AI tool Grok was used to create sexualised images of real people.

Meanwhile in December 2025 the EU fined X €120m (£105m) over its blue tick badges, saying they "deceive users" because the firm is not "meaningfully verifying" who is behind the account.

Social media analyst Paolo Pescatore said the latest announcement was a "reality check" for TikTok - and a "warning shot" for every social media platform.

"The market is shifting from 'maximise engagement' to 'engineer responsibility' - and regulators now have the tools to enforce it," he said.