How to verify a peptide supplier's lab report

A certificate of analysis is only useful if you can check it independently. A PDF that lives only on the seller's website proves nothing except that the seller can make a PDF. Here is how to tell a verifiable report from a decorative one.

Checks that carry weight

• Independent hosting. The strongest reports are published to a third-party laboratory's own system, reachable at a domain the seller does not control. If everyone links to the same independent host, that host becomes a shared trust anchor you can compare vendors against. We publish batch certificates to an independent verification host for exactly this reason.
• Batch matching. The lot number on the report must match the lot number on the vial you received. A report for a different batch is not about your material.
• A named method. The certificate should state the analytical method, the detection wavelength and the reference standard. "Purity: 99%" with nothing behind it is not a result.
• The chromatogram and spectrum. The raw traces should be present, not just the conclusions drawn from them.
• A test date. Recent analysis for the current batch; an undated report tells you nothing about age.

Red flags

• A purity figure quoted to decimals with no method, trace or batch number.
• A report that cannot be opened anywhere except the seller's own page.
• The same certificate reused for every product or every batch.
• Numbers that change between the product page and the certificate.
• Pressure to trust the brand instead of the document.

What you are really buying

In this category the structural problem is that you cannot test every purchase yourself. The substitute is a report produced by someone else, tied to your batch, hosted somewhere the seller does not own. That is what makes a claim checkable rather than a promise.

We list every published batch on the lab test results page and explain each section in how to read a certificate of analysis. Purity and identity are worth understanding too: see HPLC purity explained and peptide identity and mass spectrometry.