Google’s AI Overviews, which appear at the top of search results and are seen by about 2 billion users each month, cite YouTube more often than any medical website when answering health-related questions, according to a new study.
The research, conducted by SE Ranking, analysed responses to more than 50,000 health queries made in Germany. It found that YouTube accounted for 4.43% of all citations used in AI Overviews, more than hospitals, government health agencies, medical associations or academic institutions. YouTube is owned by Google.
Researchers warned this matters because YouTube is not a medical publisher and hosts content from a wide range of creators, including non-experts. Although some highly cited videos came from hospitals or licensed professionals, these represented less than 1% of all YouTube links used in health summaries.
The study found AI Overviews appeared in more than 82% of health searches. After YouTube, the most cited sources were German public broadcaster NDR, followed by medical reference site MSD Manuals and consumer health portal NetDoktor.
Google said the findings could not be generalised globally and argued that AI Overviews are designed to surface high-quality information, including expert-created YouTube content. However, independent experts said the results suggest a structural issue, with visibility and popularity outweighing medical authority in how AI health information is generated.
