Vendor Evaluation Checklist
A weighted checklist across 7 categories for organising your own research on a seller. The weights are our editorial judgement, not a validated score, and a high score is not evidence of what is in a vial.
What the checklist does
The checklist organises what you can find out about a seller into 33 items across seven categories: testing and certificates, sourcing and transparency, reputation, the website, the product as it arrives, service and shipping, and pricing and red flags. Tick an item when you have confirmed it, or mark it not applicable. Each category has a weight, and each item a weight within its category; your score is the weighted share of applicable items you have confirmed, out of 100, and the rating bands run from Avoid through Poor, Fair and Good to Excellent at 90 and above. Everything stays in your browser.
The weights are our editorial judgement about what matters most, with testing weighted highest. They are not a validated scoring system, and nothing on this page names or rates any seller.
What a checklist cannot tell you
No amount of ticking tells you what is in a vial. When researchers bought semaglutide from online sellers operating without a prescription, the vials they tested contained 29% to 39% more than their labels said, and every one contained bacterial endotoxin, although the sellers presented themselves as legitimate.1 A seller can have a professional website, fast shipping and good reviews and still send the wrong amount of the wrong thing. The checklist helps you spot sellers that fail the basics; it cannot certify one that passes them.
Reading a certificate of analysis
The testing items carry the most weight because a certificate is the only document that claims to describe the contents. Check that it is specific to the batch you received, that the batch number matches your vial, that the lab is independent of the seller and named so you can contact it, that it reports purity with the chromatogram behind the number, that it confirms identity by mass spectrometry, and that anything meant for injection has an endotoxin result against a stated limit. Our COA decoder reads a pasted certificate and flags the common problems, including a purity of exactly 100%, a missing lot number or date, no chromatogram and no endotoxin test.
Red flags worth more than their weight
- Claims that a product treats or cures anything. A seller making therapeutic claims about an unapproved product is telling you it does not follow the rules.
- Research-use-only wording offered as reassurance. It says nothing about quality and does not make a product legal for people to take.
- Certificates that are generic, undated or unverifiable. A certificate you cannot tie to your batch or confirm with the lab is decoration.
- No company address or legal entity. If something goes wrong, there is no one to hold to account.
For the wider question of what grey-market peptides are and how their quality has actually been measured, see our guide to evaluating a peptide source and our verification hub.
Sources
- Ashraf, A. R. et al. (2024). Multifactor Quality and Safety Analysis of Semaglutide Products Sold by Online Sellers Without a Prescription: Market Surveillance, Content Analysis, and Product Purchase Evaluation Study. Journal of Medical Internet Research, 26, e65440. PMID: 39509151 · doi:10.2196/65440
This explainer describes how the tool works and what its numbers rest on. It is not medical advice and does not recommend any dose or product.