Third-Party Tested Peptides: The COA for Every Lot

What a certificate of analysis says

A certificate of analysis is a document that reports analytical tests performed on one specific batch of material. For a research peptide, a useful COA answers three questions: is this the stated compound, how pure is the sample, and which lot was tested.

A COA from a research peptide company should include at least the following elements:

• Identity: the compound name and, where relevant, its sequence or composition.
• Purity by HPLC: the percentage of the main peak relative to all detected peaks in the chromatogram.
• Mass spectrometry confirmation: the observed mass compared with the expected molecular mass of the compound.
• Lot number: the identifier that links the report to the printed label on the vial.
• Test date and issuing laboratory: when the analysis was performed and who performed it.

How to read a COA field by field

Start with the header. The product name, the lot number and the date should all be legible and should match the material you are checking. A report without a lot number cannot be tied to a specific vial.

Next, read the HPLC section. Look for the method summary, the detection wavelength and the reported purity figure. The chromatogram, when attached, should show one dominant peak; the purity number is the area of that peak as a share of the total integrated area.

Then read the mass spectrometry section. The report should state the expected mass and the observed mass, or show a spectrum with the main ion labeled. Agreement between the two supports the identity of the compound; it does not by itself say anything about purity, which is why both tests appear together.

Finally, check the signature block: the laboratory name, the analyst or reviewer, and the report date. These fields tell you who is responsible for the numbers on the page. For a step-by-step walkthrough with examples, see our guide on how to read a peptide COA.

What “third-party” means, and why it differs from in-house testing

Third-party testing means the analysis is performed by an independent laboratory that is not the seller and not the manufacturer of the material. An in-house analysis is performed by the same company that makes or sells the product.

Both can be technically valid, but they are not the same thing. An independent laboratory has no commercial interest in the outcome of the test, and its name on the report gives you a second party you can identify. That is why buyers searching for third-party tested peptides look first at the issuing laboratory on the COA.

Our approach is simple: the COA states which laboratory issued it, so you do not have to take the word “third-party” on trust. You can read it on the report yourself.

How to verify your lot

Every vial label carries a lot number. Enter that number on the Verify a lot page to see the published record for that batch, including the manufacturing and testing dates, the reported purity and a link to its COA when it is available.

Lot records are published as each batch’s report becomes available. If a lot does not appear yet, contact us with your order number and we will send the documentation for that lot directly. Before buying, you can also request the COA of the lot currently in stock on WhatsApp.

What the COA shows, and how to check it before you buy

The COA is the record you can check before you buy: it shows the compound identity, the HPLC purity figure, the mass spectrometry result, the lot number, the test date and the laboratory that issued the report. Reading those fields against the vial label tells you exactly which lot the document describes.

You can request the COA of the lot currently in stock before you buy, on the Verify a lot page or on WhatsApp. If you receive a vial whose label lot number does not match its documentation, or if the documentation is missing, contact us with your order number and photos of the label.

Damaged, defective or wrong items reported within 14 days of delivery, with the order number and photos, are replaced or refunded under our returns policy.