This page explains how Checkthevendor.com produces a vendor grade, who signs off on it, and the rules that keep our scoring honest.
We rate vendor quality only. We do not rate, and take no position on, the safety, effectiveness, legality, or suitability of any peptide for any purpose. We do not sell peptides, and nothing on this site is medical, dosing, or health advice.
A grade is our editorial opinion, grounded in disclosed, dated facts. We publish the facts we relied on and the date we gathered them so you can check our reasoning and reach your own conclusion.
We are independent from the vendors we grade
We are not owned by, operated by, or controlled by any peptide vendor. We do not take payment to raise a grade or change a ranking.
We do earn money through affiliate links and clearly-labelled sponsored placements. That is a hard line, not a soft preference: money never affects a grade or a ranking. The same published rubric applies to paying and non-paying vendors alike. Sponsored slots are visibly labelled and kept out of the merit ranking, and affiliate links are disclosed where they appear.
If a vendor pays us and earns a poor grade, it gets the poor grade.
How a grade is produced
Every vendor is scored against eight criteria, each weighted to sum to 100%:
| Criterion | Weight | Type |
|---|---|---|
| Third-Party Lab Testing & COA Verification | 25% | measured |
| Measured Purity & Contaminant Profile | 18% | measured |
| Transparency & Disclosure | 12% | mixed |
| Reputation & Customer Service | 12% | editorial |
| Pricing & Value | 10% | measured |
| Shipping, Packaging & Fulfilment | 8% | mixed |
| Payment Options & Checkout Trust | 8% | mixed |
| Website & Operational Trust Signals | 7% | editorial |
Each criterion is scored 0-100 against a published rubric, multiplied by its weight, and summed into a single 0-100 composite. The composite maps to a letter grade:
A+ 97-100 · A 93-96 · A- 90-92 · B+ 87-89 · B 83-86 · B- 80-82 · C+ 77-79 · C 73-76 · C- 70-72 · D+ 67-69 · D 63-66 · D- 60-62 · F below 60.
The integrity gate
Two rules can override the arithmetic, because some failures matter more than a weighted average can show:
- A vendor with no independent third-party COA cannot score above a D, no matter how strong the rest of its profile looks.
- A vendor we find publishing fabricated or reused COAs, or fake reviews, is capped at F and flagged on its profile. We describe the specific observation we documented and the evidence behind it, and let you draw your own conclusion.
The two-step reviewer sign-off
No grade is published on one person’s say-so.
- A reviewer gathers the evidence, scores each criterion against the rubric, and writes up the reasoning with sources attached.
- A second, independent reviewer checks the evidence against the scores, confirms each measured claim is backed by a linked source, and signs off before publication.
If the two reviewers disagree, the grade is not published until the disagreement is resolved against the rubric and the evidence.
Conflict-of-interest rule
No one who has a financial tie to a vendor may score that vendor, at either step. A financial tie includes ownership, employment, paid consulting, commission beyond standard disclosed affiliate terms, or any personal stake in that vendor’s sales.
Where any such tie exists, it is disclosed on the affected vendor’s page, and the work is reassigned to a reviewer with no tie. This rule applies to both the first reviewer and the sign-off reviewer.
How we gather and keep evidence
Every score is tagged either measured (a verifiable fact, with the evidence linked) or editorial (clearly labelled opinion, grounded in the same disclosed facts). We want you to be able to tell the difference at a glance, and to check our work.
Our evidence comes from three kinds of source:
- Independent test-buys. We buy products as an ordinary customer would and send them to an independent lab (for example, Janoshik) for analysis.
- Vendor-published COAs. When a vendor publishes a certificate of analysis, we verify it against the named lab and the stated lot before we rely on it.
- Community-reputation sampling. We sample reputation using a documented method: named sources, a stated date range, a minimum number of data points, and exclusion of outliers and astroturfed activity.
We retain the underlying evidence and the dates it was gathered so a grade can be traced back to what supported it.
Confidence labels
Because evidence is not equally deep for every vendor, each grade carries a confidence label:
- High — at least one independent test or per-lot COA in the last 12 months, and at least 20 independent community data points.
- Medium — an independent COA is present but sparse, or there are 5 to 19 community data points.
- Limited / provisional — vendor-supplied data only, fewer than 5 data points, or any criterion left unscored.
A strong score carrying a Limited label means exactly what it says: promising on the evidence we have, but the evidence is still thin.
How often we re-review
Grades go stale, so we refresh them on a set cadence:
- Pricing & value — quarterly.
- COA and purity — per new batch; otherwise every 6 months, with an independent test-buy refresh at least annually.
- Reputation — every 6 months.
- Full re-grade — annually, or whenever our methodology changes.
Corrections and right of reply
We can get things wrong, and facts change. Every vendor we grade has a free right of reply, and anyone can flag an error through our corrections process. If a documented fact is wrong, we correct it and note the change.
Our grades remain our editorial opinion, grounded in disclosed, dated facts. Where a vendor’s own claims are relevant, we report what that vendor states as a fact about that vendor, rather than adopting it as our own position. This includes any framing a vendor applies to its own products; we report such framing as the vendor’s claim, not as our endorsement of it.
Who stands behind these grades
Editorial reviewer: [NAME], [TITLE / CREDENTIALS — e.g. analytical-chemistry or lab-testing background], [years] reviewing vendor and lab-testing data. Sign-off reviewer: [NAME], [TITLE / CREDENTIALS]. Replace these placeholders with the named editor and sign-off reviewer responsible for this methodology.
Contact us
Questions, corrections, or a right-of-reply request: email hello@checkthevendor.com. Tell us the vendor, the specific claim or score in question, and any supporting evidence, and we will route it to a reviewer with no tie to that vendor.