Question · from the living review of Vitamin B12 →

Is it true that vitamin B12 supplementation prevents cognitive decline in older adults?

Doubtful updated weekly · as of

Priors rates this Doubtful — 30 out of 100, updated weekly. Probably not, on current evidence. On the claim that vitamin B12 supplementation prevents cognitive decline in older adults, its four-agent AI review panel weighs 20 primary peer-reviewed studies.

RefutedDoubtfulUncertainLikelyEstablished
where this sits on Priors’ scale of how settled the evidence is

How we got this answer. Priors runs each claim through a panel of four AI agents, each acting as a specialist expert reviewer. They read the published, peer-reviewed studies behind the question, judge how strong, consistent and reliable the evidence is, and turn that judgment into a single rating from 0 to 100 — refreshed every week as new studies appear, so it reflects where the evidence stands today, not a one-off verdict.

The traceable studies behind this rating — and the panel’s single strongest counter-argument to it — are in Priors’ full Vitamin B12 review.

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Reflects the peer-reviewed evidence as of 17 July 2026 and updates as new studies land. AI can make mistakes. Not medical advice.