How to Read a Certificate of Analysis

A Certificate of Analysis (COA) is a document from a laboratory that reports the results of testing performed on a specific batch of product. A legitimate COA should include: the name of the testing laboratory (which should be independently verifiable), the date of analysis, the compound tested, the batch/lot number, and the results for each test performed. The laboratory should be ISO 17025 accredited or equivalent, and you should be able to verify their credentials independently.

The most critical tests on a peptide COA are identity confirmation and purity. Identity is typically confirmed via mass spectrometry (MS) or HPLC-MS, which verifies that the molecular weight of the compound matches the expected peptide sequence. Purity is measured by HPLC (High-Performance Liquid Chromatography) and expressed as a percentage. For research peptides, aim for 98% or higher purity. Lower purity means the remaining percentage consists of synthesis byproducts, truncated sequences, or other impurities that could cause unpredictable effects.

Additional tests you should look for include endotoxin testing (LAL test, measuring bacterial endotoxin levels that indicate sterility of manufacturing), residual solvent analysis (confirming manufacturing solvents have been removed), and amino acid analysis (verifying the correct sequence). Some COAs include appearance (should be white to off-white powder), solubility testing, and pH measurement of the reconstituted solution. A COA that only shows purity without identity confirmation, or that lacks the testing laboratory's name and accreditation, should be treated with skepticism.