When browsing Canadian peptide suppliers, you'll notice that nearly every vendor claims "99%+ purity" on their products. But what does peptide purity actually mean? How is it measured? And how can you verify whether a supplier's purity claims are legitimate rather than just marketing language? This article breaks down the science of peptide purity, explains how testing works, and provides practical guidance for evaluating any supplier's quality claims. Peptide purity refers to the percentage of the sample that consists of the target compound versus impurities. The industry standard for measuring peptide purity is High-Performance Liquid Chromatography (HPLC). A legitimate COA should include both HPLC purity data and mass spectrometry identity confirmation. Every product sold by Durham Peptides is tested by Janoshik Analytical.