How to choose a research peptide supplier: a UK buyer's checklist

1. Is there a Certificate of Analysis for your batch?

Not a sample CoA on the homepage: one that carries the batch number printed on your vial. The guide to reading a CoA explains which fields to check. A supplier that cannot connect a document to a specific batch cannot show you what is in the vial.

2. Does the CoA show data, or only claims?

Look for a chromatogram and a mass spectrum, not just a table that says 99%. Raw traces can be wrong, but they can at least be examined; a bare number cannot.

3. Can the batch be verified independently?

Online batch lookup, a testing-lab reference or a QR code that resolves to the lab's own record all raise the cost of faking documents. Nordapep, for example, lists a Certificate of Analysis per batch and offers online batch verification.

4. Is the product described precisely?

Names should match the molecule: sequence or CAS number, salt form where relevant and the quantity in the vial. Ambiguous names matter. CJC-1295, for instance, is used for two different molecules, with and without a drug affinity complex.

5. Is pricing transparent per size?

Vial sizes differ between suppliers, so compare the price per mg. The price per mg table and the cost planner do this arithmetic for every Nordapep size.

• Larger vials usually cost less per mg.
• A very low per-mg price is a reason to ask what is in the vial, not a bargain.

6. Does the supplier stay within research claims?

Suppliers of genuine research materials describe them as being for in vitro or laboratory use. Pages that suggest human or animal use, give dosing, or promise outcomes are making claims the product cannot support.

7. Is the supplier a real, contactable business?

Look for a registered company name, an address and a working contact route. Reviews help only when they are on third-party sites you can verify.

8. How is the product packed and labelled?

Sealed, labelled vials with the compound, quantity and batch number make traceability possible. Unlabelled or generically labelled vials undo the value of any CoA.

9. Are storage instructions given?

A supplier that understands the material will say how to store it. See the guide on handling lyophilised peptides for the general principles.

10. Will they answer a technical question?

Ask which method was used for purity, which lab ran it and when. A good supplier answers in a sentence; a poor one deflects.