How to Read a Certificate of Analysis (COA)
A certificate of analysis is a laboratory’s measured report on one specific batch, and it only means something if you can check three things: who tested it, which lot it covers, and what was actually measured.
What a COA is
A COA reports what an independent laboratory measured in a sample from one production lot. It answers two questions about the material in the vial: is it the compound it is supposed to be (identity), and how much of the material is that compound rather than something else (purity and content).
A COA does not describe what a compound does, and it says nothing about any use. It is a quality document for researchers, like the spec sheet that comes with any laboratory reagent.
The three measurements
Most peptide COAs report three results. The table uses the independent report for Vantage NAD+, lot 26032501, tested by BT Labs (West Palm Beach, FL).
| Measurement | What it tells you | NAD+ lot 26032501 | Specification |
|---|---|---|---|
| Identity (FTIR) | The infrared spectrum is a fingerprint. It confirms the material matches the expected compound. | Identity confirmed | Matches reference |
| Purity (HPLC) | Chromatography separates the components of the sample. Purity is the share of the main peak among all peaks. | 99.9% | at least 98% |
| Potency (assay) | The measured amount of the compound compared with the amount on the label. | 105.4% (1054.5 mg measured vs 1000 mg labeled) | 90–110% |
Read them together. A purity figure with no identity test only says the sample is one clean substance, not which one. An identity result with no purity figure says nothing about what else is present.
Why the total mass is not the labeled amount
Lyophilized (freeze-dried) material often contains a stabilizer, also called an excipient, along with the compound. The COA for lot 26032501 shows this: total mass 1243.9 mg, made of 1054.5 mg of the compound plus 189.4 mg of excipient, a ratio of about 1 to 0.2.
So the labeled amount (1000 mg) refers to the compound, not the whole powder. A COA that separates the two lets a researcher know the real net content of the compound. One that only reports a total weight cannot.
Five checks that a COA is real
- A named, independent laboratory. The lab’s name, address and accreditation or certification should be on the report, and it should not be the seller.
- A lot number that matches your vial. A COA for a different lot tells you nothing about yours.
- A report date and a sample identifier. Old or undated reports may not cover the current batch.
- Specifications next to each result. A number with no acceptance range cannot be judged.
- The original file, not a screenshot. Vantage publishes the original lab PDF at vantagepeps.com/verify: enter the lot number printed on the vial and the report for that lot opens.
If any of the five is missing, ask the seller before relying on the report.
This article is educational information about laboratory documentation. Vantage Peptides products are sold for laboratory research use only. Not for human consumption.