Why methodology matters
Most supplement sites grade products on a scale they invented, using criteria they don't share. We think the methodology should be the product.
The evidence grade
Every product on The Proof Stack receives a grade based on the quality of human evidence behind its primary claims:
- Grade A — Multiple RCTs and/or meta-analyses; consistent, meaningful effect.
- Grade B — Some RCTs or strong mechanistic evidence. Promising but not conclusive.
- Grade C — Emerging or primarily mechanistic. Interesting but not settled.
What counts as evidence
We tag every source by study type, strongest to weakest: meta-analysis, human RCT, human observational, animal, mechanistic, expert protocol, anecdote. The grade is the editorial summary; the source tags let you see the basis.
The Hype Check
Some popular supplements don't meet our evidence floor. Rather than ignoring them, we explain what is known, what is not, and why the evidence is not there yet.
How we pick brands
A product earns a brand recommendation only if it uses a bioavailable form, states dosing clearly, passes independent third-party testing, and avoids unnecessary fillers.