A study reveals that teenagers on TikTok are exposed to highly targeted undisclosed advertisements, bypassing the European Union's prohibition on profiling minors for ads. Researchers found that while formal ads comply with the law, hidden promotional content dominates and is aggressively personalized. This loophole in the Digital Services Act allows platforms to deliver commercial material disguised as regular posts.
The European Union's Digital Services Act (DSA) prohibits profiling minors for advertising purposes, but it applies mainly to formal ads purchased through a platform's system. A recent study highlights a significant gap: undisclosed promotional content, such as influencer marketing without required labels, continues to target teens effectively.
Sára Soľárová at the Kempelen Institute of Intelligent Technologies in Slovakia and her team created automated accounts simulating 16- to 17-year-old teenagers and 20- to 21-year-old adults. These bots were given interests like beauty, fitness, or gaming and interacted with TikTok's For You feed for one hour daily over 10 days, viewing 7,095 videos in total.
Among these, 19 percent featured advertisements, with 56 percent being undisclosed. Formal ads for minor accounts were limited or absent and showed no personalization. In contrast, undisclosed ads were tailored to the bots' interests—for example, 92.1 percent matched a beauty interest for a simulated 16-year-old girl.
The study measured hidden profiling as five to eight times stronger than allowed for adult formal ads, based on interest-matching rates. Undisclosed ads comprised 84 percent of those seen by minors, compared to 49 percent for adults.
"The only way for us as a society to understand social media is to study it behaviourally, and this is the way we do it," Soľárová said. She added, "Formally, TikTok complies with the law because it does not profile the formal ads to minors... But the disclosed ads represent a small proportion of the total commercial content on the app."
TikTok declined to comment. Catalina Goanta at Utrecht University noted, "These undisclosed ads are a new form of targeted advertising... platforms are able to seamlessly deliver more commercial content." She emphasized that regulators have viewed influencer marketing too narrowly and that undisclosed ads harm consumers. Soľárová agreed, stating, "We have to expand the definition of what advertising is."
The findings are detailed in a preprint on arXiv (DOI: 10.48550/arXiv.2603.05653).
