A COA can look official. Read it anyway.

A certificate of analysis is a lab report. It is not a seal of approval. The number people quote, usually a purity figure from HPLC, tells you how much of what the instrument detected matched the main peak. It does not tell you whether that peak is the peptide on the label, whether the vial is sterile, or whether anything the method cannot see is also in there.

Three questions do most of the work. Does the batch number on the certificate match the batch number on the vial? Is the testing lab named, and is it independent of the seller? Is there a second method, such as mass spectrometry, confirming identity rather than just purity?

None of this is a reason to buy anything. It is a reason to read the whole page before trusting a number that was designed to be screenshotted.

Sources

1. Regulator statementCertain bulk drug substances for use in compounding that may present significant safety risks (opens in a new tab)US Food and Drug Administration, current as of April 2026. Repeatedly cites peptide-related impurities and identity testing as open problems

We link to the paper, the trial registry, or the regulator, never to a seller. A study type in the label tells you who or what was actually studied.

Spotted an error or a newer study? Tell the editors. Corrections are noted on the page. Our standards.

Education only. Not medical advice.