How to Read a Peptide Certificate of Analysis
A certificate of analysis describes tests on a submitted sample. Learn which questions it answers, which it leaves open and how to check the report.
Evidence updated September 6, 2026 · PurePeptideHub Research Team · Independent clinical review pending.
Key Takeaways
- Match the report to the exact sample and batch before interpreting results.
- Identity, measured amount, chemical purity, sterility and endotoxin are different questions.
- A report does not establish that a product is approved, clinically effective or safe to inject.
1. Establish what was tested
Start with traceability: the report number, laboratory, sample description, lot identifier and test dates. FDA emphasizes knowing ingredient suppliers and verifying the quality of components. A report for a different lot does not document the lot in front of you.
Source: FDA: Know Your Bulks and Excipients Suppliers- 1.Match the compound name and molecular identity; similar names can describe different molecules.
- 2.Match the batch or lot number rather than relying on a filename or a vendor logo.
- 3.Identify who selected and submitted the sample. Do not assume a vendor-submitted sample represents every finished vial.
2. Separate the measurements
Laboratories use different tests for different attributes. Read the method, result, unit and acceptance criterion together. If a report only describes chemical analysis, do not infer a microbiological result from it.
Source: FDA: New York Medical Products Laboratory — analytical and microbiological testing- 1.Identity: what evidence supports that the sample is the named substance?
- 2.Amount or assay: what quantity was measured, in which units and on what basis?
- 3.Purity: what impurities can this method detect, and which are outside its scope?
- 4.Microbiology: are sterility and bacterial endotoxin results actually reported, with their methods and limits?
3. Interpret “99% purity” cautiously
Ask what the percentage is a percentage of. A chromatographic peak-area result is not automatically a measurement of total mass in a vial. Water, counterions and substances a method does not detect can complicate interpretation. Request the method and a clear explanation of the result basis from the laboratory.
Source: FDA: New York Medical Products Laboratory — analytical and microbiological testing- 1.Avoid converting a purity number directly into a claimed dose or vial content.
- 2.Check whether the amount claimed on the label was measured separately.
- 3.Treat an omitted test as missing information, not a pass.
4. Check the laboratory and the report
Verify a report through the laboratory’s independently located contact details or verification service. Accreditation concerns competence for specified activities; check the laboratory’s current scope rather than treating a logo as blanket approval.
Source: ILAC: What laboratory accreditation covers- 1.Confirm that the report identifier resolves to the same sample and results.
- 2.Check any claimed accreditation with the relevant accreditation body.
- 3.Ask whether the test methods on this report fall within that scope.
5. Keep sterility separate from chemical purity
FDA treats microbiological control as part of a wider manufacturing and testing strategy. Even a sterility result is not a guarantee about every unit, future handling or the entire supply chain. Adding a preservative or seeing a clear solution is not a substitute for validated controls.
Source: FDA: Production and Process Controls — microbiological control- 1.Do not interpret an HPLC purity result as a sterility result.
- 2.Distinguish sterility from bacterial endotoxin testing.
- 3.A report cannot establish a treatment’s clinical benefit or make an unapproved product approved.
Frequently Asked Questions
Does a COA prove that a peptide is safe to inject?
No. A COA documents particular tests. It does not establish clinical safety, effectiveness, an appropriate dose or the quality of every finished unit.
Can a genuine report be irrelevant to the product I received?
Yes. It might concern a different lot, an ingredient rather than a finished product, or a selected sample whose representativeness is unknown.
What should I do if a test is missing?
Record it as missing. Ask the laboratory or a qualified professional what evidence would be needed; do not infer a pass from silence.