Google’s AI Overviews, which appear at the top of search results and are viewed by about 2 billion people each month, cite YouTube more often than any medical website when answering health-related questions, according to new research.
The study, conducted by SEO platform SE Ranking, analysed more than 50,000 health searches made in Germany and found that YouTube accounted for 4.43% of all citations used in AI Overviews. No hospital network, government health authority or academic institution was cited as frequently. The next most referenced sources were German public broadcaster NDR, the medical reference site MSD Manuals, consumer health portal NetDoktor and the doctors’ platform Praktischarzt.
Researchers warned this was significant because YouTube is not a medical publisher and hosts content from a wide range of creators, including non-medical influencers. They argued the findings suggest AI Overviews may prioritise visibility and popularity over medical authority.
Google said the results could not be generalised beyond Germany and that AI Overviews are designed to surface high-quality information from reputable sources in multiple formats. It added that much of the YouTube content cited comes from hospitals, clinics and licensed professionals, though researchers noted such videos made up less than 1% of all YouTube links cited.
Independent experts said the study adds weight to concerns that risks from AI-generated health summaries are structural rather than isolated, particularly given Google’s recent removal of AI Overviews from some medical searches after cases of misleading information.
