How to read a peptide COA in two minutes
Written by Emily Kang, Beauty & Wellness Editor · Reviewed by Sarah Mitchell, RD, CNS, Lead Reviewer & Registered Dietitian
Last updated November 10, 2026
Last updated November 10, 2026
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A certificate of analysis is the only evidence you have about what is in a vial. Here is how to read one.
What it is
A COA is a lab report for one production lot. A real one is issued by a laboratory, names the lot, and reports how pure the sample is and whether it is the right molecule.
Five things to check
| Line on the COA | What you want to see |
|---|---|
| Lot or batch number | Matches the number on your vial |
| Laboratory | An outside lab, named, that you can look up |
| Purity (HPLC) | A percentage, 99% or higher for a quality lot |
| Identity (mass spec) | Measured mass matches the expected mass |
| Date | Recent, and after the lot was made |
Red flags
- One PDF used for every lot.
- No lab name, or an in-house report only.
- Purity quoted on the website but not on a document.
US Peptide Labs uses AxisPharm for lot testing and prints a QR code on each vial that opens that lot's report, which is why it scores 4.8 or higher on documentation in our ranking.
⚠️ Research use only. These compounds are sold for laboratory research and are not FDA-approved medicines. Trial figures on this page describe the pharmaceutical molecules studied under medical supervision.