What is a peptide COA?

What a COA contains

WHO's model COA lists the tests performed, the results obtained and the acceptance criteria. For a repackager's or trader's COA, WHO guidance says the original manufacturer's COA should accompany it.

For laboratories accredited to ISO/IEC 17025, the standard sets what a test report must carry. Summaries from an accreditation body list the laboratory's name and address, a unique report identifier, the customer, identification of the item tested, the method, dates, results with units, and the person authorizing the report. The standard itself is paywalled, so we read it through that summary.

Who issues one

A manufacturer can issue a COA from its own testing, and an independent laboratory can issue one for a sample sent to it. Either way the document speaks to the sample that was tested. Whether that sample came from the batch in your hand is a separate question the document cannot answer by itself.

What the rules say for drug makers

These rules govern drug manufacturers under current good manufacturing practice, not peptide sellers in general. They show how FDA treats supplier COAs. Under 21 CFR 211.84(d)(2), a manufacturer may accept a supplier's report of analysis only if it runs at least one specific identity test and validates the supplier's results at appropriate intervals. Under 21 CFR 211.194(a), laboratory records must hold complete data from all tests, including graphs, charts and spectra from the instruments.

What a COA does not show

• That the product is safe or effective for human use.
• That the vial you hold came from the tested batch.
• Anything about tests that are not listed on it.
• FDA's warning letters to peptide sellers turn on intended use. The three we checked for this page (Gram Peptides, Pinnacle and USApeptide.com) do not mention COAs.

Evidence that COAs and measured results can differ

A peer-reviewed 2015 study bought 98 synthetic peptides from research suppliers, each ordered at 95% purity or higher. Only 44.0% met the required purity, and the authors reported a large discrepancy between supplier COAs and their own quality control. These were research-synthesis suppliers in 2015, not the current retail market.

A 2026 preprint that has not been peer reviewed reported testing 6,441 samples of 14 compounds sold as research-grade and found that 41.6% to 71.1% failed basic quality criteria. Treat it as preliminary.