Supplement decision tools
Evidence Grade Glossary
Understand what a study, brand claim or product test can actually tell you. Evidence type is a starting point, not a guarantee that a supplement works.
See what a source can tell you, what it cannot, and what to check next. This is not an automatic evidence grade.
Why this matters
Supplement content often blends human trials, animal work, mechanism explanations, label testing and brand claims. They answer different questions.
Third-party testing can support label trust but does not prove a health outcome. A systematic review can also be uncertain if its underlying studies are small, inconsistent or poorly matched to the question.
How this tool works
Select the source type to see its purpose and limitations. Independent testing and brand claims are separate choices. The result does not award a numerical score or a clinical evidence grade.
Cochrane explains outcome-specific evidence certainty, including bias, inconsistency, indirectness, imprecision and publication bias. Design alone is not enough.
Before trusting a claim, ask: Who was studied? Was the same ingredient, formulation and amount used? What outcome changed, by how much, and with what uncertainty? A study of an ingredient is not automatically proof for every finished product.