A receptor is a protein on or inside a cell that receives chemical signals. A molecule with the right shape can bind to it, like a key fitting a lock.

Purity is the share of a product that is the named compound itself, usually written as a percent. A 99% pure material is 99% that one compound and 1% everything else.

A peptide is a short chain of amino acids — the same building blocks that make up proteins — joined together in a set order.

HPLC (high-performance liquid chromatography) is a lab method that separates a mixture into its parts so an analyst can measure how much of each part is present.

A Certificate of Analysis (COA) is a lab report for one specific batch of a product, listing the tests that were run and the results they gave.