How We Research and Grade Supplements
Every claim on this site gets an evidence grade from A to D. Here is how they work and why they matter.
The short version
We read the studies so you don't have to. Every claim on this site gets an evidence grade from A (strong research support) to D (not enough data to say much). We show our work, link every source, and don't sell supplements. That's the deal.
Why we built our own grading system
Most supplement content falls into two camps: academic papers nobody reads, or marketing dressed up as health advice. We wanted something in between — rigorous enough to be honest, clear enough to be useful.
We built SB-EGS by taking the best elements from established frameworks: the domain-based scoring from GRADE, the nutrition-aware approach from NutriGrade, the plain-language communication from NESR, and the study-design hierarchy from Oxford CEBM.
The result is a 5-domain, 20-point system that produces letter grades any reader can interpret, while maintaining the rigor of established evidence evaluation. The current rubric version is sb-egs-v1.0.
How we grade evidence
Every supplement-outcome claim gets scored across five dimensions. The total score maps to a letter grade.
The five dimensions
What kind of research exists? Meta-analyses of RCTs score highest. Single pilot studies score lowest.
How many people were studied? More participants means more confidence.
Do the studies agree? If most studies find the same thing, that's consistent.
Does it actually make a meaningful difference? We care about real-world impact, not just p-values.
Was the research done on people like you, taking the supplement the way you'd take it?
From score to grade
| Score | Grade | What it means |
|---|---|---|
| 17-20 | A | Strong evidence |
| 15-16 | A- | Strong-to-solid |
| 13-14 | B+ | Solid evidence |
| 11-12 | B | Moderate evidence |
| 9-10 | B- | Moderate-to-emerging |
| 6-8 | C | Preliminary |
| 0-5 | D | Insufficient |
Hard rules that override scores
- •Only one study exists? Cap at B, no matter how good it was.
- •Only animal or lab studies? Cap at C.
- •No human studies at all? That's a D.
- •Every study funded by the manufacturer with no independent replication? Downgrade by one letter.
Safety is separate
A supplement can have an A grade for effectiveness and still have safety concerns. We flag safety independently as Generally Safe, Caution, or Warning.
Where we get our data
Primary sources
- •PubMed/MEDLINE — the world's largest biomedical research database
- •NIH Office of Dietary Supplements — government fact sheets, RDA values, safety data
- •Supp'Buddy Evidence Database — our curated database, continuously updated
Cross-reference sources
- •Examine.com, SUPP.AI, and CrossRef/DOI verification
What we don't do
- •We don't sell supplements. No affiliate links, no sponsored content.
- •We don't give medical advice. Evidence grades tell you how strong the research is.
- •We don't hide uncertainty. If the evidence is mixed, we say it's mixed.
- •We don't cherry-pick. If studies disagree, you'll hear about all of them.
Questions?
If you want to understand a specific grade or think we got something wrong, reach out at contact@supp-buddy.com. We take corrections seriously.
See our grading in action
Every article on this site uses the grading system above. Start here:
The SB-EGS methodology was developed by the Supp'Buddy Research & Editorial Team, drawing on GRADE, NutriGrade, NESR, and Oxford CEBM Levels of Evidence — adapted for consumer supplement research.