Research
Evidence hierarchy
How Healthy Mango grades the evidence behind each compound, and why the A–D scale is a starting point rather than a verdict.
- Last updated:
- 2026-07-22
Overview
Every compound page displays an evidence level (A, B, C, or D) that summarises the quality and quantity of the human evidence available for that molecule. Level A is strong evidence from multiple well-designed randomised controlled trials; level D is preclinical evidence with little or no human data. Levels B and C sit between them.
The grading is deliberately simple. It is meant to help readers orient themselves quickly, not to substitute for reading the underlying literature.
Why it matters
Peptides at the same stage of scientific interest can differ dramatically in the depth of evidence supporting them. A one-line evidence tag on the page header lets a reader see the difference at a glance.
Key concepts
Level A
Multiple well-designed randomised placebo-controlled trials, typically with regulatory approval for a defined indication. Effect sizes are consistent across trials.
Level B
Published human trials (often phase 2 or a single phase 3) with consistent signals, not yet regulator-approved for the reported use — or approved for a distinct but related indication.
Level C
Small human studies, uncontrolled reports, or heterogeneous published series; sometimes with regulatory approval in a limited jurisdiction.
Level D
Mechanistic, in-vitro, or animal-model evidence without meaningful human trial data.
Common misconceptions
- "Level A means safe." Level A is a statement about evidence, not about individual-reader safety.
- "Level D means dangerous." Level D means under-studied. Some level-D compounds are promising research targets; others are inappropriate for human use outside a controlled trial.
- "The level is objective." Evidence grading involves editorial judgment. Where a reader disagrees with a grade, the underlying references are cited on the page for independent evaluation.
Practical interpretation
Use the evidence level as a first-pass filter. Then read the Evidence Snapshot and the References accordion on the compound page for the substantive story.
Limitations
The A–D scale collapses many dimensions (trial size, follow-up length, effect size consistency, safety data) into one letter. It is a summary, not a substitute for reading.