According to Digital Trends, a December 2025 analysis of over 50,000 German-language health searches revealed a surprising trend in Google’s AI Overviews. YouTube was the most-cited source, making up 4.43% of all citations, which amounted to 20,621 links out of 465,823 total. This put it far ahead of established medical reference sites like NetDoktor and MSD Manuals. The study also found that only 36% of the links cited by the AI appeared in Google’s top 10 organic search results, meaning the AI is pulling in content users might not normally see. Furthermore, when sources were grouped by reliability, 65.55% came from sources without strong evidence-based safeguards, while government and academic sources combined for only about 1%.
The YouTube Doctor Is In
Here’s the thing that should give you pause: YouTube wasn’t just a top source, it was the top source. And by a wide margin. It was cited about 3.5 times more than NetDoktor. Think about that for a second. When you’re asking about a weird symptom at 2 AM, the AI’s confident summary might be leaning more on a video from a wellness influencer than on a vetted medical manual. That’s a fundamental shift in how information is being presented. The AI isn’t just summarizing the “best” or most authoritative result from page one of Google. It’s digging deeper, but into what? A video ranking 11th in organic results can suddenly become the primary citation in that box at the top of your screen. That’s a huge amount of visibility being handed over.
Why This Is Happening
So why is this happening? I think it comes down to the AI’s training and what it’s optimized for. Large language models are trained on massive amounts of internet data, and YouTube transcripts represent a colossal, easily digestible dataset of people explaining things. The AI might be identifying clear, conversational explanations of symptoms from those videos, even if the medical rigor isn’t there. It’s basically finding an answer that sounds good and is readily available in its training data. But sounding good isn’t the same as being correct, especially in medicine. This also hints at a potential conflict in Google’s ecosystem: they own YouTube. Is there an unconscious bias, or even a designed one, to keep users within Google’s own properties? It’s a question worth asking.
How To Use This Safely
Look, I’m not saying you should never use AI for a quick health query. But you have to change how you use it. Treat the AI overview as a conversation starter, not a diagnosis. That confident paragraph at the top? View it with skepticism. The real product is the citations list below. Click through. Scan those links. Is it a hospital (.org), a government health agency (.gov), or a reputable medical publisher? Or is it a YouTube channel and a personal blog? Your next click should be to those higher-quality sources. And never, ever let an AI summary outweigh actual professional medical care. This was one study in Germany, but the model is global. The principle is universal: trust, but verify. And maybe verify a lot.
