How to check whether a research peptide supplier is worth ordering from

Every shop in this market says the same three words. Very few will show you the document behind them, and of those that do, a good share are showing you something that cannot survive a closer look. This page is the checklist, and at the end it is our own answers — including the two we cannot give you.

It is worth knowing what is actually at stake. In 2024 a team at the University of Pécs bought semaglutide from six online pharmacies selling it without a prescription, at the lowest prices, and analysed the vials by liquid chromatography coupled with mass spectrometry. Of 1,080 links collected from search results, 134 (42.3%) led to 59 unique illegal online pharmacy sites, and the top 30 domains involved accumulated over 4.7 million visits between July and September 2023. The three vials that actually arrived failed in ways no label could have predicted: measured purity between 7.7% and 14.37% against 99% claimed, semaglutide content 28.56% to 38.69% above the labelled amount, and endotoxin in every sample, between 2.1645 and 8.9511 EU/mg. Not one of the three prefilled pens arrived at all — those orders were non-delivery scams.

A separate screening by the Scientific Institute of Public Health in Belgium took a different angle: instead of comparing a label to a measurement, it screened the ten most frequently encountered falsified peptide drugs on the Belgian market for impurities of every class — active-substance related, small-molecule contaminants, elemental impurities and residual solvents. Purity ranged from 5% to 75% for cysteine-containing peptides, and the samples carried arsenic and lead, with several up to ten times the ICH toxicity limit for parenteral drugs. Speciation confirmed all the arsenic was in the more toxic inorganic form.

Nobody is arguing that every seller is selling this. The point of quoting it is narrower: the failure modes are measurable, they are common, and every one of them is visible in a document before you order — if you know which document fields to look at.

The nine checks

1. Is the issuing laboratory named, and findable? A certificate that says “our in-house QC” has told you nothing you could verify with a third party.

2. Is there a lot or batch number? This is the field that carries the most weight and the one most often missing. A COA describes one batch. Without a lot number it describes nothing in particular — including the batch in your parcel.

3. Is there an assay date? Peptides degrade; a report from four years ago is a historical document about a product that may no longer exist in that form.

4. What was measured, and by what method? “Purity” alone is not a measurement. HPLC and mass spectrometry answer different questions, and a report that names neither cannot be checked by anybody.

5. Is the result a number? “Passed” is not a result. “99.1%” is. This one check separates most documents from decoration.

6. Does the salt form on the report match the vial? Peptides are sold as the hydrochloride salt or the acetate salt; they are different substances with different masses and different behaviour. A report for the wrong salt form says nothing about what is in the tube.

7. Does the report’s verification key resolve at the lab’s own verification page? This is the fastest test available to a buyer. Janoshik Analytical, the lab behind most of the reports circulating in this sector, publishes a verification page where the key printed on the report is typed in and the lab’s own record comes back. A key that does not resolve is a document somebody edited.

8. Does the lot number on the report match the lot number printed on your vial? If the shop will not tell you the lot number before you order, that is the answer.

9. Does the vendor say what it does not publish? This is the check almost nobody runs, and it is the one that separates a seller from a mirror. Every honest supplier in this market has a documented gap: they do not manufacture, or they do not have a report for that product, or they cannot test what they did not make. A seller with no gaps has not answered the question.

Our own answers

We are a reseller. We do not manufacture anything, we do not repack anything, and every item ships in its maker’s sealed packaging with the maker named on the product page. That also means the batch documentation we can offer is exactly the batch documentation our makers publish — no more.

• Nine products have a published batch report. They are Med Care Pharma’s, issued by Janoshik Analytical, transcribed with the laboratory, the lot number, the date and the measured values on each product page. They are the only nine.
• The other 101 products have no report, because their manufacturers publish none. Nordic Peptides, Marvel Nutrition and PharmaRx publish no public batch documentation. Those products carry the neutral label Original packaging / no repacking · tracked. We would rather say that than print a number we cannot stand behind.
• We do not sell a report we did not receive, and we do not relabel another laboratory’s report as our own QC.
• We do not write dosing protocols. Product descriptions are the manufacturers’ own text, published as written; the purity and effect claims inside that text are the maker’s, not ours.
• The rest of the checklist you can run on us. Ask for the lot number, ask for the salt form, ask which lab ran the assay, and ask what we do not publish. If we duck one, that is worth knowing.

The deeper version of this question — what a manufacturer, a lab and a reseller each do differently, and which of the three is accountable for what — is the subject of how a peptide order moves inside the EU, and the measurement side is in how to read a certificate of analysis.

What we cannot promise

We cannot tell you that a product is pure, safe to use, or effective. Nobody can, including the laboratories: purity is a measurement of a sample, not a guarantee about a person. We cannot promise delivery times we do not control beyond the courier’s own commitment. And we make no claim about how we compare to other vendors — we have no way to substantiate that, and a page which did claim it would be quoting marketing.

⚠ Everything sold here is for in-vitro laboratory research only. Not for human or veterinary use. Nothing on this page is medical advice.