How to Verify a Peptide Certificate of Analysis

A certificate of analysis (COA) is a laboratory report for a specific lot. This hub explains the fields a careful reader should check before treating any PDF as evidence. It is educational. It is not a claim that every PureLab catalog item has a published certificate.

1. Lot number

The lot (or batch) identifier on the certificate should match the lot printed on the vial label and the lot named on the supplier’s public lot page. A COA without a lot number cannot be tied to a specific container.

2. Laboratory identity

Confirm the testing laboratory’s legal name and location as printed on the report. For PureLab’s currently published peptide lots, that laboratory is Krause Analytical, Austin, Texas. Other laboratories may issue COAs in the wider industry; this page does not claim they have tested PureLab products unless a PureLab lot page says so.

3. Report date

Note the report (or issue) date. It situates the assay in time and helps compare against the supplier’s published lot write-up.

4. Method

Common peptide identity/purity workflows use HPLC with UV detection and mass spectrometry confirmation (often summarized as HPLC-UV-MS). The method line should be explicit on the certificate.

5. Identity

Identity confirmation (for example by MS) answers whether the main analyte matches the named compound — separate from how pure the chromatographic peak is.

6. Chromatographic purity

Chromatographic purity is typically the area percent of the main peak versus other peaks under the stated method. It is not the same as “how many milligrams are in the vial.”

7. Measured content (assay vs label claim)

Measured content compares recovered mass to the labeled mass (for example mg found versus mg claimed). A high purity percentage can coexist with content below the label claim. See chromatographic purity vs measured content for PureLab’s two published examples.

8. Authenticity checks

• PDF metadata and letterhead consistency with the named lab
• Lot string match across vial, invoice/order notes, and public lot page
• Method and analyte name match the product you received
• Independent contact with the laboratory when you need third-party confirmation (labs differ in whether they offer public portals)

Krause Analytical–specific workflow

PureLab’s published Retatrutide and BPC-157 lots were reported by Krause Analytical. For a Krause-focused authentication walkthrough (including the fact that Krause has no public lot-lookup portal), use the dedicated guide:

How to verify a Krause Analytical peptide COA

That Krause page remains the detailed reference and is not replaced by this hub.

Related PureLab resources

• COA library and machine-readable lots.json
• Lot testing hub
• How to read a GLP-1 peptide COA