How we test
Every result follows the same chain, documented and time-stamped, and publishes with the raw lab report attached. Nothing below changes because of who a vendor is.
Buy blind
We order as a normal retail customer, through anonymous addresses and rotated payment methods, off the same public shopping cart everyone else uses. No vendor may send us samples directly. A vendor who doesn't know a vial is headed for a lab can't cherry-pick it.
Capture the claim
In the same session we place the order, we archive the vendor's published COA and product page — the PDF where one exists, plus a full-page screenshot — with a SHA-256 hash, the capture timestamp and the source URL. That snapshot is what a comparison is made against.
Test & compare
The sample goes to an independent accredited lab under a coded ID. It runs HPLC-UV purity, LC-MS identity and net content, LAL endotoxin, sterility and a fentanyl screen. Both COAs publish together with the discrepancy table.
Chain of custody
Every sample carries timestamps at each handoff: purchased, received, shipped to lab, received by lab, results in, published. Those dates appear on the result. A result without a complete chain doesn't publish.
The lab receives coded sample IDs rather than vendor names wherever the workflow allows, so a result isn't shaped by whose vial it is.
How verdicts are decided
Verdicts are thresholds applied to measurements, not judgments about a vendor. They are published here so a reader can check our arithmetic against the attached documents:
- Pass — measured purity and mass fall within methodology margin of the vendor's own COA and the product's label.
- Underdosed / marginal — a measurable shortfall that is real but not gross: typically a purity gap of a few points, or a vial short of its labeled mass.
- Fail — a significant discrepancy: purity materially below claim, mass materially below label, identity not confirmed, or a contaminant finding.
How the Pep Score is calculated
A rank is arithmetic applied to attached lab documents. The score is 70% quality and 30% verified value:
- Pass rate (30) — across all tested batches, weighted toward recent results.
- Purity accuracy (20) — average gap between claimed and measured purity.
- Label accuracy (15) — average gap between labeled and measured milligrams.
- Transparency (5) — the vendor publishes a real COA, from a named lab, with a batch number that matches what shipped.
- Verified value (30) — verified $/mg against the median for that same peptide, so semaglutide vendors are compared to semaglutide vendors.
Ranking rules: a vendor needs at least two tested batches to receive a score at all (one test shows as Provisional). A verified fail caps the score at 49 until a later blind retest passes. Scores decay after twelve months without a fresh test, so passing once buys nothing permanent. Tiers are 90+ Verified Elite, 75–89 Recommended, 50–74 Mixed Results, below 50 Not Recommended.
Limitations — what a result does not tell you
A result describes the specific batch we bought, on the date shown. Batch-to-batch variance is real and expected; a pass is not a guarantee about a vendor's next production run, which is exactly why every vendor returns to the testing queue rather than earning a permanent badge.
Analytical methods have margins of error. Where a measurement falls inside that margin we say so rather than presenting it as a discrepancy. We report what the lab reported; we don't extrapolate to claims about safety or suitability for any use.
Questions about methodology are welcome, and corrections are published. See also why this testing exists and our terms.