Where to source research peptides

Certificates of analysis (COA)

A useful COA is tied to a specific batch or lot number that matches the vial label, shows the test date, and names the laboratory. Be wary of one generic PDF reused for every batch, or a purity number with no chromatogram behind it.

Third-party HPLC and mass-spec testing

HPLC checks purity (look for the chromatogram, not only a percentage). Mass spectrometry checks that the molecule is the right one. Reports from a third-party lab — for example Janoshik — usually carry more weight than in-house sheets alone. For injectable research material, endotoxin (LPS) testing is a further quality marker when it is available.

Purity figures and red flags

• Purity stated without a matching batch COA, or a COA that does not match the lot on the vial.
• No mass-spec identity check, or only a marketing claim of “pharma grade” with no data.
• Prices far below the market for the same peptide and fill size, with no test reports.
• Vague or missing storage and shipping information for lyophilised powder.
• Pressure to pay outside normal card or invoice channels, or no tracking on the parcel.

Storage and shipping

Lyophilised peptides are usually kept cold and dry, away from light. Reconstituted solutions are far less stable. Follow the conditions on the supplier’s documentation. For shipping, check how vials are packed (cold packs when needed), whether the parcel is tracked, and how long transit typically takes — long warm journeys are hard on freeze-dried powder.

Where people look

If you want research peptides shipped from within the EU, peptides-eu.net is one catalogue that publishes third-party test reports per product.

For worldwide delivery straight from the manufacturer in packs of ten vials, see PeptidesX10.

Nobody quoted elsewhere on this site endorses any supplier. Apply the checks above to any source you use.