Peptide COA Testing: What a Certificate of Analysis Shows (and Doesn’t)
For in vitro laboratory research use only. This article explains laboratory documents only. Peptix makes no claims about the effects of any material it sells.
“COA” appears on almost every research peptide product page, but the term is often used loosely. A Certificate of Analysis is a specific document with specific limits. Knowing what it shows, and what it does not, helps a laboratory decide how much weight to give it.
What a COA is
A Certificate of Analysis is a report issued by a testing laboratory after it analyzes a sample. For research peptides, the sample is usually a vial taken from a production lot. The certificate records who submitted the sample, when the lab received it, when the report was issued, which tests were run, and the results.
What a COA shows
A typical peptide certificate includes:
- Client, accession number and search code: identify the submission at the testing lab.
- Received / Reported: when the lab received the sample and when it issued the report.
- Lot: the batch the sample came from. A certificate applies only to that lot.
- Purity (HPLC-UV): the share of the main peak in the chromatogram measured by high-performance liquid chromatography with UV detection, reported as a percentage.
- Identity (LC-MS): liquid chromatography with mass spectrometry, used to check that the measured mass matches the expected compound. The result line names what was identified.
- Net content: the amount the lab measured in the tested vial, as printed on the certificate. It can differ from the labeled amount stated on the product label.
- Chromatogram and mass spectrum: the raw traces behind the results.
For a field-by-field walk-through, see our guide on how to read a certificate of analysis.
What a COA doesn’t show
This is the part that is easy to miss. A certificate reports results for the sample tested. It is not a guarantee for other lots.
In practice that means:
- It covers one lot. A certificate for one lot says nothing about a different lot, even of the same product.
- It covers the sample tested. The lab analyzed a sample drawn from the lot. The certificate does not describe each individual vial.
- It covers the tests listed. If a test is not on the certificate, the certificate does not tell you about it. A purity result alone does not confirm identity, and the reverse is also true.
- It describes a point in time. The report date tells you when testing happened. It does not describe how material was stored afterwards.
- It says nothing about use. A COA is an analytical document. It does not describe what a material does or whether it suits any purpose.
Why the testing lab matters
A certificate is only as useful as your confidence in where it came from. Look for a named, independent laboratory and a way to confirm the report on the lab’s own site. Current Peptix lots are tested by Freedom Diagnostics, and each listed certificate has a search code for lookup on the lab’s website.
Example: current Peptix lots
| Product | Lot ID | Purity (HPLC-UV) | Identity (LC-MS) | Measured net content per COA |
|---|---|---|---|---|
| BPC-157 10 mg | BC-20260521-01 | 99.26% | BPC-157 | 12.71 mg (labeled 10 mg) |
| TB-500 10 mg | TB-20260521-01 | 99.79% | thymosin beta-4 | 12.15 mg (labeled 10 mg) |
| BPC-157 / TB-500 20 mg | BB-20260521-01 | 99.15% | BPC-157 and thymosin beta-4 | 13.68 mg BPC-157 + 11.17 mg thymosin beta-4 (labeled 10 mg + 10 mg) |
Source: the Peptix COA page, Freedom Diagnostics reports dated July 8, 2026. A certificate reports results for the sample tested. It is not a guarantee for other lots.
The measured net contents above are higher than the labeled amounts. That is simply what the lab measured in the vials it tested; the label states the labeled amount.
All current certificates are on the peptide COA lookup page, alongside the research peptides they belong to, such as the BPC-157 / TB-500 20 mg blend.
Frequently asked questions
What is a peptide COA?
A Certificate of Analysis is a report issued by a testing laboratory after it analyzes a sample. It records the lot, the dates, the tests run and the results.
Does a COA apply to every vial?
No. A certificate reports results for the sample tested from one lot. It does not describe each individual vial, and it is not a guarantee for other lots.
What tests appear on a Peptix COA?
Current Peptix certificates report purity by HPLC-UV and identity by LC-MS, along with the measured net content.
What does net content mean on a COA?
Net content is the amount the lab measured in the tested vial, as printed on the certificate. It can differ from the labeled amount stated on the product label.
For research use only. Not for human or animal use.
