Google’s AI Overviews cite YouTube more frequently than any medical website when responding to health-related searches, according to a new German study that raises concerns about how health information is prioritised for a tool used by about 2 billion people a month.
Researchers analysed more than 50,000 health queries made in Germany and found YouTube accounted for 4.43% of all cited sources in AI Overviews, making it the single most referenced domain. No hospital network, government health body or academic institution came close. While some highly cited YouTube videos came from reputable medical channels, the researchers stressed these represented less than 1% of all YouTube links used.
The study suggests AI Overviews often favour visibility and popularity over medical authority. Critics warn this could increase the risk of misleading or harmful health advice, especially since anyone can upload content to YouTube, including non-experts.
Google said its AI summaries are designed to surface high-quality information and that many YouTube citations come from licensed professionals and trusted institutions. However, independent experts argue the findings show structural risks in how AI Overviews are designed, rather than isolated errors.
The research follows earlier reports of inaccurate medical information appearing in AI Overviews, renewing scrutiny of the feature’s role in shaping public understanding of health.
