How evidence grading works
Every claim in M-1 carries one of four grades. Here's what they mean, and how they're assigned.
Multiple high-quality studies generally point in the same direction, though no study can guarantee an individual outcome.
There is reasonably consistent research, but important limitations or unanswered questions remain.
Early, limited, mixed, or indirect research. Some people may find this useful, but we can't be confident about the average effect.
Insufficient or very uncertain research for a health-effect claim. It's included because people ask about it, not because it's established care.
Who assigns a grade, and how
Grades are assigned during content curation, by the people who write and source each claim — not generated or scored by AI. Each grade reflects the quality and consistency of the underlying research (study types, sample sizes, and whether independent studies agree), not just whether an effect exists at all. A Very limited evidence grade is included because people ask about the topic, not because the approach is established care — absence of strong evidence is treated as a distinct message from evidence that something doesn't work.
Keeping claims current
Every source behind a claim is automatically re-checked against PubMed and Crossref on a monthly cycle, to catch broken links or citations that no longer resolve. A claim whose source needs a fresh look is marked "Due for review" on its card; one actively being revised is marked "Under revision." It's normal and expected for a small number of sources to come back unverified — some are deliberately honest "no peer-reviewed study found" placeholders, not broken citations. Every claim carries the date of its last review, shown on its card, so you can see how current it is at a glance.
Conflicts of interest
M-1 doesn't accept payment, free product, or any other consideration from a treatment maker, supplement brand, or device manufacturer in exchange for how a claim is written or graded. Grading follows the published research a source actually reports, not commercial interest in a particular outcome.
Think a claim is wrong or outdated?
Tell us — this is a small, human-curated library, and a second look genuinely helps. Use the Contact form on Terms of Service or Privacy Policy and mention the claim and why you think it needs a second look. This isn't a channel for individualized medical advice — see when to seek urgent help for that — but it is how a claim actually gets revised.