How to read a peptide COA.
A Certificate of Analysis (COA) is a lab report for a specific production batch of peptide. A trustworthy COA names the batch, dates the test, states the methods used, and reports purity, content, and identity results. If a COA has no batch number, no date, or no method names, treat it as evidence of nothing.
What a COA is
A Certificate of Analysis is a document issued by (or on behalf of) a manufacturer reporting the test results for a specific production batch. Its job is traceability: the batch number on the COA should match the batch number on the vial you hold.
The sections to check, one by one
- Batch or lot number — the single most important field. No batch number means the document can't be tied to your material. See batch-specific COAs.
- Test date and report date — tests age. A COA from three years ago says nothing about a vial filled last month.
- Testing lab — a named laboratory with accreditation is a plus; "in-house testing" alone is weaker evidence.
- Appearance — physical description (e.g., "white to off-white lyophilized powder").
- Purity result and method — e.g., "≥99.0% by HPLC." A purity number without a method is not verifiable. See peptide purity and HPLC.
- Peptide content (net content) — how much of the mass is actually peptide, after water and counterions. See peptide content.
- Identity confirmation — molecular weight by mass spectrometry (LC-MS) and/or retention time. See identity testing.
- Safety panels — endotoxin testing, sterility testing, and heavy metals where applicable.
Red flags on a COA
- No batch number, or a batch number that doesn't match your vial
- No test date, or an undated template
- "Typical values" language — meaning the numbers are not from your batch
- Purity claimed with no method named
- No laboratory or signatory identified
- Perfect identical numbers across batches — real batches vary slightly
For how forged documents circulate, see our article fake COAs are real.
How to verify
Cross-check the batch number against the vial. If the seller publishes a COA library, confirm your lot appears in it. Where possible, prefer sellers whose COAs include identity testing and endotoxin results rather than purity alone.
Questions. answered.
What should a peptide COA include?
At minimum: a batch number matching your vial, a test date, the lab's name, the testing methods, and results for purity, content, and identity. Endotoxin and sterility panels are a strong plus.
Can a COA be faked?
Yes. Templates are copied and numbers edited. Cross-referencing batch numbers and asking for method-level detail filters out most low-effort forgeries.