Grades are a promise about the kind of evidence, not about how well it works. A and B ship. C is published and not sold. F is published as a warning.
Grades
Evidence grades
Grades are a promise about the kind of evidence, not about how well it works. A and B ship. C is published and not sold. F is published as a warning.
| Grade | Means | Ships |
|---|---|---|
| A | Multiple RCTs or meta-analyses in humans, at this dose, for this outcome. | Yes |
| B | At least one good RCT at this dose, or consistent RCTs with heterogeneity in effect. | Yes, grade printed on label |
| C | Mechanistic, animal, or small uncontrolled trials only. | No. Review published. |
| F | Evidence of no effect, or of harm, at the doses sold elsewhere. | No. Review published. |