Supplier verification
Last reviewed 23 July 2026
You can evaluate a research-peptide supplier objectively, without taking any claim on trust, by checking a short list of things that are either present or absent: batch-specific certificates published openly, a named and contactable third-party laboratory, a vial whose batch number matches its certificate, stated test methods, honest handling of bad batches, and a real, identifiable business behind it all.
The criteria below are written to be equally valid on any supplier's website, including a competitor's. A checklist that only ever flatters one company is a sales page in disguise, and a careful reader notices. This one is meant to be used against anyone — us included.
The strongest signal is a certificate of analysisCertificate of analysis (COA)A document reporting the analytical test results for a specific batch of material, issued by the laboratory that tested it.Full definition → that is specific to the batch you are buying and published openly, rather than a generic document supplied only on request. A public, batch-specific certificate lets anyone match a vial to its own results; a generic one cannot be tied to the material in your hand.
Testing should be third-partyThird-party testingAnalysis performed by an independent laboratory with no commercial stake in the result, a stronger evidence claim than in-house testing.Full definition → — performed by an independent laboratory that is named and can be contacted directly. Independence removes the incentive to report a flattering figure, and contactability is what makes the result verifiable rather than merely stated. An in-house number is a weaker claim.
The batch numberBatch (lot) numberA unique identifier assigned to a single production run, linking the physical vial to its own certificate of analysis.Full definition → physically on the vial should match the number on the published certificate. This is the link that turns a certificate into evidence about your material. If the vial carries no batch number, or it does not match, the certificate proves nothing about what you received. Reading a certificate of analysis covers how to make this check.
A specification should state the methods behind its figures — reverse-phase HPLC for purity, mass spectrometry for identity, amino acid analysis for net peptide content — not just a bare percentage. A number without a method is not verifiable, and often conceals which of the two purity-related numbers is being quoted.
Look for clear research-use-onlyResearch use onlyA regulatory labelling category for materials supplied for laboratory research, not authorised as therapeutic goods for human or veterinary use.Full definition → labelling and an absence of health or medical claims. A supplier that makes health claims about research materials is itself a compliance risk, and that risk extends to its buyers. Restraint here is a sign the supplier understands the regulatory framework it operates in.
Stock held locally and shipped with sensible cold-chainCold chainThe unbroken sequence of temperature-controlled storage and transport that keeps a temperature-sensitive material within its specified range.Full definition → handling reduces transit time and temperature exposure. It also means a real inventory exists, rather than an order being drop-shipped from an unknown origin with an unknown history.
How a supplier handles an out-of-specification or moisture-damaged batch is one of the clearest quality signals there is. Withdrawing and destroying compromised stock — and being open about it — is the correct decision even though it is costly. A supplier that hides or ships bad batches is telling you how it will behave when something goes wrong.
Finally, the ordinary markers of a legitimate business: a registered entity, a contactable support channel staffed by people, and a clear physical jurisdiction. These are basic, but their absence is a meaningful warning.
Use this as a printable checklist — it is also included in the downloadable PDF guide. A supplier that clears every line is describing itself honestly:
Every criterion above is one you can check against Au Peptide Labs. That is the point of publishing it: a supplier confident in its testing has no reason to fear a checklist, and every reason to hand you one.
How to read a certificate of analysis
What should a certificate of analysis actually show, and how do you verify it?
Peptide laboratory testing methods
Which tests prove what about a peptide, and what does each one miss?
Purity versus net peptide content
Why isn't the milligram figure on a vial the amount of peptide you are getting?