How We Score Peptide Vendors: The Rubric, Explained

Every vendor score on this site comes from the same six-factor rubric, applied the same way whether we earn a commission from that vendor or not. This post explains the rubric itself, how the weights were chosen, and — just as importantly — what we don't do to arrive at a score.

The six factors

• COA transparency (30% of the default weighting) — whether Certificates of Analysis are published, come from a named third-party lab, and are dated recently enough to reflect current batches.
• Reputation (20%) — a structured sweep of public sentiment across Reddit, Trustpilot, and BBB, with filtering for astroturfed or vendor-adjacent content.
• Pricing (15%) — price per milligram measured against category benchmarks, sourced from live catalog listings rather than promotional snapshots.
• Policies (15%) — how clearly a vendor posts its shipping, refund, and payment-method terms.
• Shipping (10%) — stated shipping speed, carrier, and packaging practices as published by the vendor itself.
• Catalog (10%) — breadth of the peptide and blend catalog, and depth of documentation at the individual product level.

COA transparency and reputation together account for half the default score, which is deliberate: documentation you can independently verify and sentiment from people who actually ordered are the two factors hardest to fake convincingly at scale, and the two most correlated with the closures and enforcement actions we've tracked separately.

How the weights combine into one number

Each factor is scored 0-10 in one-decimal increments, and the overall score is a weighted average using the percentages above, rounded to one decimal. We also publish reweighted 'best for' lenses — best for bulk pricing, best for fast shipping, best for COA transparency, widest catalog, and best for beginners — using the same six underlying scores with different weight distributions, rather than a separate research process for each lens. That's a deliberate choice: one dataset, several honest views of it, instead of a new number invented for each headline.

Why we don't do hands-on testing, and say so

We do not place orders with any vendor and we do not run our own lab analysis. Every score on this site traces to public-data desk research: published COAs, live catalog pricing, public policy pages, and public community sentiment. That's a real limitation, not a footnote — it means our confidence in a score is only as good as what a vendor has chosen to make public and what independent reviewers have separately verified. Where a vendor gates pricing behind a login (Limitless Biotech, Peptidology) or omits a lab name from its COAs (Biotech Peptides, Core Peptides), our review says so explicitly rather than filling the gap with an estimate.

A score on this site reflects public documentation, not a verified lab result. Treat it as a starting point for your own diligence, not a substitute for it.

Re-review cadence

Given how quickly this category has moved — four major vendor closures in roughly two years, an active FDA enforcement wave, and state-level compounding rules changing mid-2025 — a score that isn't revisited goes stale fast. We re-check each vendor's dossier on a quarterly cadence at minimum, and sooner when a specific triggering event occurs: an FDA warning letter, a reported operational disruption, or a material change to a vendor's published COA or pricing pages. Every review carries a 'last reviewed' date so you can see exactly how current the underlying research is.

Where we earn money, and how that's separated from scoring

Some links on this site are affiliate links, and we earn a commission on qualifying purchases from some of the vendors we review, including a vendor, One Tap Peptides, that we have a direct commercial relationship with. That vendor is scored on the identical rubric described above, with no adjustment for the relationship — including in cases where the honest score is lower than we'd prefer, such as its shorter reputation track record as a newer entrant. Full detail on that relationship and how we handle it is in our affiliate disclosure.