How to Read a Certificate of Analysis

A Certificate of Analysis (CoA) is a document issued by an analytical laboratory that confirms the identity and purity of a specific product batch. In the peptide industry, CoAs are your only objective proof of what's actually in a vial. The problem is that not all CoAs are created equal, and some companies exploit this by providing misleading or incomplete documents.

The first thing to check is the testing laboratory's name. A legitimate CoA will clearly identify the independent lab that performed the analysis. If the document just says "tested" without naming the lab, or if the lab name matches the peptide manufacturer, that's a red flag. Independent third-party testing means the lab has no financial incentive to produce favorable results. At Purity Lab, our CoAs name the testing laboratory because we want you to know exactly who verified what's in your vial.

Next, look for HPLC (High-Performance Liquid Chromatography) results. HPLC is the industry standard method for measuring peptide purity. The report should show a specific purity percentage, research-grade peptides should test at 98% or higher. The HPLC chromatogram (the graph showing peaks) should have one dominant peak representing the target peptide and minimal impurity peaks. If a CoA doesn't include HPLC data, it's incomplete at best.

Mass Spectrometry (MS) results confirm molecular identity. The observed molecular weight should match the known molecular weight of the peptide within a narrow margin. This confirms that the substance is actually the peptide it claims to be, not a different compound or a degraded fragment. A CoA with purity data but no identity confirmation is only half the picture.

Always verify that the batch number on the CoA matches the batch number on your product label. A generic CoA without a specific batch reference is essentially worthless, it might represent a completely different production run. Also check the test date. Testing should be recent and specific to your batch. A CoA from two years ago tells you nothing about the product you're holding now.

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