How to Read a Peptide Certificate of Analysis (COA)
A certificate of analysis (COA) for a research peptide is a laboratory report that answers three questions about a specific sample: is it the compound the label says it is (identity, usually by mass spectrometry), how much of the material is that compound (purity, usually by HPLC, stated as a percentage), and how much is in the vial (net content or total mass, in milligrams). A certificate that answers all three, names the laboratory, carries a certificate number you can check, and can be matched to the vial in your hand is a real one. A certificate that skips any of those is a picture.
What is on a peptide COA, section by section
Laboratory and certificate number. The name of the testing laboratory and a unique report number appear at the top. Independent laboratories (the certificates on our Résultats de laboratoire page come from SideChain Analytics, AV Analytics and others) issue numbers in a series and many run a public lookup where the number can be entered to confirm the report is theirs. If there is no laboratory name, or the “lab” is the seller, the document is a product sheet, not a certificate.
Sample identification. The compound name, the label claim (for example 10 mg), a sample or lot identifier, the client the test was run for, and the dates the sample was received and analysed. The lot identifier is what lets a buyer connect the certificate to a physical vial; look for the same identifier on the label.
Identity. Mass spectrometry measures the molecular weight of what is actually in the vial and compares it with the expected weight of the named peptide. Certificates show the observed mass (often written as the [M+H]+ ion) against the theoretical value, and state whether identity is confirmed. This is the section that rules out a different compound being sold under the right name.
Purity. High-performance liquid chromatography (HPLC) separates the sample into its components; the percentage of the total signal that belongs to the main peak is the purity figure. Research-grade peptides typically test above 98%. The chromatogram itself is usually reproduced on the certificate, and a serious report states the method conditions (column, gradient, wavelength) so the result could be repeated.
Net content. The measured mass of peptide in the vial against the label claim. A 10 mg vial that assays at 10.4 mg is a normal result; fill accuracy is stated as a percentage on some certificates. This is separate from purity: a vial can be 99% pure and still under-filled, or full and impure.
Other tests, when present. Appearance (a white lyophilised powder is the norm; GHK-Cu is blue), water content, endotoxin and microbial limits, and peptide content by amino-acid analysis appear on some certificates and not others. Their absence is not a red flag on a purity certificate; their presence is extra information.
How to check that a certificate is genuine
- Find the laboratory’s own website and use its lookup, where one exists, to confirm the certificate number. A QR code or “scan to verify” block on the certificate points to the same place.
- Check the dates. A certificate should predate or match the batch it describes, not the date of your order by years.
- Match the compound, the label claim and the lot on the certificate to the vial. A single certificate re-used across every size and every batch of a product is a common shortcut.
- Read the numbers rather than the summary line. “Pass” means the result met the laboratory’s or the client’s threshold; the purity percentage and the observed mass are the actual evidence.
- Ask for the PDF as the laboratory issued it. Screenshots cropped to a purity figure, certificates with the laboratory name removed, and purity figures of 99.99% on a template with no chromatogram are the usual signs of something fabricated.
What a COA does not tell you
A certificate describes the sample that was tested. It says nothing about how the material was stored after testing, whether the vial you receive came from the same production run unless the lot matches, or whether the compound does anything at all. Purity and identity are the whole scope. Suppliers who present a certificate as proof of an effect are mixing two different documents.
How Vistara Labs publishes certificates
Every compound in the catalogue has its certificate listed on the Résultats de laboratoire page with the purity figure beside it and the PDF exactly as the laboratory issued it, including laboratory name, certificate number and lot. Certificates are replaced when new testing comes in, so the page, not a cached PDF, is the current record. Questions about a specific certificate go to [email protected].
Vistara Labs supplies peptides as laboratory research materials. A certificate of analysis documents identity, purity and content of a tested sample; it is not a statement about any use of the material.
Questions fréquentes
What purity should a research peptide have?
Research-grade peptides typically test above 98% by HPLC. The number is the share of the chromatogram’s signal in the main peak; read it alongside the identity result, since a pure sample of the wrong compound is still the wrong compound.
Is a COA the same as third-party testing?
Only when the laboratory is independent of the seller. A certificate issued by the manufacturer or the retailer is in-house testing; a certificate from a named independent laboratory with a checkable number is third-party testing.
Why does the certificate show a client name that is not the shop?
Testing is commissioned by whoever submits the sample, which may be the manufacturer, a distributor or the shop. The laboratory’s name and certificate number, and a lot that matches the vial, are what make the document usable, regardless of who paid for the test.
Does a COA cover every vial in a batch?
It covers the sample tested, which the laboratory draws from the lot named on the certificate. Matching the lot on the certificate to the lot on the vial is the closest link a buyer can make.
Can I verify a certificate myself?
Often, yes: independent laboratories run public lookup pages keyed to the certificate number, and many print a QR code on the report that opens the same record.
