Two questions before you pay, one check when the box arrives. Asked the same way for every peptide supplier we assess — same rubric, same weights, same bands, whether the supplier pays us or not.
This is the score. A supplier with too little evidence to assess gets no score at all — never a low one — so a seller with nothing to show can’t undercut an honest mid-tier supplier on price alone.
Benchmarked against 477 priced SKUs from 17 supplier catalogues, quoted on labelled weight. Same-molecule spreads run from 1.5× to more than 3×, so “expensive” and “cheap” only mean something against the band.
The paperwork you were shown before you paid is not always the paperwork that turns up in the box. When your order arrives, scan the certificate that came with it. PepiScreen reads the lot number, the lab, the peptide and the measured purity straight off that document and checks all four against the batch you were sold — and against every other certificate in our corpus.
If that lot number has already been used for a different peptide, if the lab never issued the report, or if the declared contents don’t reconcile with the mass on the label, you find out now — while the order is still fresh enough to dispute.
Across the certificates we can quantify, delivered peptide runs from 87.7% to 100.4% of the labelled dose. Almost nothing over-delivers, and the shortfall is real but modest. That is a figure about documents, though: it describes what suppliers’ own paperwork reports, not what is in the vial on your bench. Proof and Price tell you which supplier to buy from. Match is the only step that speaks to the vial you actually received.
0–100 measures how well a supplier's paperwork PROVES its claims — not product safety, and not the promise of any specific batch. It is an evidence score, applied identically to every supplier.
Every certificate opened, every field cross-checked, lab identity confirmed with the issuing laboratory, batch numbers traced end-to-end. The deep review.
Same rubric applied to what a supplier publishes openly — website transparency, published lab attestations, verify codes. Faster; less depth. Useful when a supplier hasn't yet shared full paperwork.
This page is the plain-English summary. Three companion documents go beneath it — for physicians, regulators, and anyone who wants to audit us.
The full methodology, weighted rubric, AI-vs-human split, data mapping, and explicit limits of what a rating can and cannot tell you. Written for doctors and regulators.
Read the methodology →The four ways buyers verify peptide suppliers today, side-by-side with real cost figures. Includes the structural-independence argument no lab-testing brand can copy.
See the comparison →How members co-write the standard: contribution categories, voting weights, Governing Council composition, ethical rules. The transparency of how the rules can change.
Read governance →