Experts Echo EU Concerns Over TikTok’s Ad Transparency Gaps

The European Commission has shared its preliminary view that TikTok fails to comply with key transparency obligations under the Digital Services Act (DSA), the EU’s online content rulebook.

In preliminary findings published Thursday, the Commission said TikTok failed to provide adequate information about the advertisements running on its platform. Specifically, the Commission said the company did not sufficiently disclose the content of the ads, who they were targeting, or who was paying for them. Additionally, it said, TikTok’s current system did not allow the public to search and review its ad library—another key requirement under the DSA.

TikTok responded by saying it was examining the Commission’s assessment and that it remained committed to fulfilling its DSA obligations. “While we support the goals of the regulation and continue to improve our ad transparency tools, we disagree with some of the Commission’s interpretations and note that guidance is being delivered via preliminary findings rather than clear, public guidelines,” the company said in a statement quoted by Reuters.

The investigation into TikTok was launched in February 2024 and remains ongoing. In addition to advertising transparency, EU regulators are still examining other potential violations related to addictive platform design, protections for minors, and the platform’s provision of data access to researchers.

Henna Virkkunen, the Commission's executive vice-president responsible for digital policy, emphasized the importance of ad transparency in the press release published by the Commission. “Understanding who is behind an ad and how audiences are targeted is vital for protecting public interest,” she said. “Whether we’re safeguarding elections, public health, or consumers from scams, people deserve to know who is influencing their online experience.”

While this latest development intensifies regulatory pressure on TikTok, it’s not the only DSA-related action the Commission has taken against the company. An earlier investigation into TikTok’s ‘Lite’ app version was recently closed after the company agreed not to introduce reward features that could incentivize excessive usage. Meanwhile, a separate probe launched in December 2024 is examining the platform’s role in the Romanian elections.

This marks the second time the Commission has taken such action under the DSA, following preliminary findings issued last year against X, owned by Elon Musk. The findings against X have not led to any fines or remedies yet.

Expert Reactions: Transparency Shortfalls Echo Longstanding Criticism

The Commission’s preliminary findings resonate with longstanding concerns from researchers and civil society groups that have struggled to use TikTok’s ad transparency tools effectively.

“I welcomed the preliminary findings against TikTok today, which align with my assessment of their ad repository,” said Fabio Votta, a political data scientist at the University of Amsterdam familiar with the platform's transparency mechanisms. “There are several shortcomings—regarding search, content, and contextual data—that, in my view, undermine its usefulness for civil society groups and researchers.”

A core issue, experts say, is the platform’s limited and unreliable search functionality. The repository often delivers irrelevant or arbitrary results, making it nearly impossible to systematically investigate specific topics such as election ads. “For example, if you want to understand if there were any ads posted about the new pope in the last weeks and you go to TikTok’s ad library, you would have to first click 30 times to change the date picker to May 2024.”

“If you then search for Leo XIV. in the search bar, you'll get 411 ads (for Germany in May 2025); you get a mix of results—about the new pope but also ads for ‘ALOE vera’ products. If you use ‘Leo XIV.’ (which in other search engines means ‘strict matches’), you'll get six million ads. These problems make the ad library very hard to use, e.g., when trying to look into ad schemes around elections,” said Martin Degeling, a (post-doctoral) researcher at AI Forensics, who has worked with TikTok’s ad library for the last few years.

“As a researcher, I haven’t been able to use the repository successfully because of the limited utility of the search and filtering functionality of the repository,” said Fabio Votta. “Accompanying texts or hashtags are missing—information that’s essential to fully understand what an ad conveys. There are also mismatches between the IDs in the ad library and the actual TikToks, making it difficult to link the two. So if I’m conducting a study on the effects of TikTok ads and tracking what participants have seen, it becomes extremely hard to connect that content to the ad library—severely limiting our ability to access key data like reach and targeting,” he told Tech Policy Press.

Experts say TikTok’s ad library not only lacks transparency around how ads are targeted and delivered but also presents significant technical barriers to meaningful research. While some targeting criteria—like age, gender, or interests—are disclosed, the data on reach is vague and lacks demographic breakdowns, making it impossible to assess how ads are distributed across audiences or detect potential algorithmic bias, said Fabio Votta, noting that he had documented bias in Meta’s ad delivery as well. Martin Degeling pointed out that they tried different ways to work around these limitations, including building their own search on the entries to find what they were looking for. But they still faced restrictive rate limits, which can result in users being blocked after only a few queries.

Jan Penfrat of European Digital Rights (EDRi) pointed out that at the moment, TikTok also falls short on transparency around its recommendation algorithms and fails to enable users to control what they are exposed to in their feeds. “The DSA mandates TikTok to provide users with an alternative recommender system that is not based on profiling, and to make this alternative easily accessible. TikTok could easily further reduce risks for users by offering alternative recommendation systems that are not optimised towards maximum engagement and screen time.” “This must urgently be fixed,” he added.

Penfrat welcomed the Commission's second preliminary non-compliance decision under the DSA but stressed that enforcement needed to be swifter to ensure timely accountability of large online platforms. “It has been over 14 months since the entry into force of the DSA, and we must unfortunately assume that any remaining non-compliance isn't accidental,” he said.

What changes would TikTok need to implement to satisfy the DSA's ad repository criteria?

Degeling of AI Forensics expressed surprise that a company as technically agile as TikTok—known for releasing app updates monthly—had left its ad library essentially unchanged for three years. Pointing to deeper operational issues or misaligned resource allocations where TikTok could improve. Many of the library’s shortcomings, they noted, could be easily addressed, such as improving rate limits for researchers and including clearer links between ads and their original videos on the platform.

Fabio Votta offered a set of detailed recommendations to bring TikTok’s ad library into compliance with the DSA and make it more useful for public interest research:

Improve Search Functionality and Query Transparency
TikTok’s search and filtering system requires a complete overhaul. Currently, queries yield inconsistent and often irrelevant results. The platform should clearly document which fields (e.g., accompanying text, hashtags, metadata, in-video text/audio) are indexed in search and offer robust filtering options by ad type (e.g., video, slide shows), funding source, and the accounts that published the ads.

Disclose Ad Content and Metadata
The repository should include comprehensive details about the advertised product or service, along with associated metadata. This includes full user-facing text (e.g., captions, hashtags, and links) and clear information about call-to-action destinations (e.g., URLs). Ad IDs in the repository should be linked to corresponding TikTok video IDs or profiles to allow traceability across paid and organic content.

Improve Targeting and Reach Transparency
Beyond vague impression ranges, TikTok should provide detailed demographic and geographic breakdowns of ad reach. Additional transparency is needed on the ad delivery algorithm and any optimization settings used (e.g., by reach, clicks, or engagement).

Provide a Fully Functional and Well-Documented API
The API should be aligned with the web interface, with full documentation and access to all relevant fields, including usernames and delivery data.

The Commission’s preliminary findings are not a final ruling, but they mark a critical juncture for TikTok. The company now has the opportunity to respond to the Commission’s assessment and potentially avoid enforcement measures such as fines up to 6 percent of its global revenue.