How to Read a Peptide COA: A Complete Guide

Section 1: Lab and Sample Information

The top of a legitimate COA should clearly state:

• Issuing laboratory name:Should be an independent third-party lab — not the vendor or manufacturer
• Laboratory address & contact:A real, verifiable physical address. No P.O. boxes.
• Sample name and lot number:Matches the product you are evaluating
• Date received and date tested:Fresh testing — old COAs applied to new lots are a red flag
• Client name:The company that submitted the sample for testing

Red flag: The lab name is the same as the vendor, or no lab name or address is visible.

Section 2: HPLC Purity Result

The HPLC purity result is the most prominent number on a peptide COA. It represents the percentage of the total sample that is the target peptide.

Also look at the chromatogram if it is included. A single dominant peak with small baseline impurity peaks indicates high quality. Multiple major peaks is a serious quality issue.

Section 3: Mass Spectrometry Identity

The MS result should confirm that the compound matches the theoretical molecular weight of the claimed peptide. Look for:

• →Observed molecular weight (m/z) vs theoretical — should match within ±0.5 Da
• →"Confirmed" or "Identity: Pass" determination
• →The specific m/z values observed and the charge states

Red flag: No mass spectrometry section at all, or MS data that doesn't include observed m/z values. A COA without MS cannot confirm the compound's identity.

Section 4: Net Peptide Content (NPC)

NPC represents the true active peptide mass as a percentage of total sample weight. A typical research peptide might have NPC of 75–85%, meaning a 10mg vial contains only 7.5–8.5mg of actual peptide — the rest is TFA, moisture, and counter-ions.

Without NPC data, dosing from weight alone is inaccurate. This is why NPC is included in all Purity + Identity panels at Gold Standard Analytics.

Section 5: Verification Information

The most important trust signal on any COA is a verifiable accession number that links to the lab's own public database.

Every COA from Gold Standard Analytics includes a unique accession number you can check at goldstandardanalytics.com/coa-lookup. If the number returns a match, the COA is genuine. If it doesn't exist in our database, the document was not issued by us.

Red flag: No accession number or verification system. Without this, you have no way to confirm the COA was not fabricated.