Purity

Purity is the proportion of a material that consists of the intended substance, with everything else counted as impurity, whether harmless or hazardous.

For a cannabinoid isolate, purity is expressed as a percentage, and crystalline cannabidiol isolate is sold as a near-pure material with the small remainder being trace cannabinoids, residual solvent, water or extraction by-products. For an extract or finished product, purity is judged not by a single number but by a panel of contaminant tests: residual solvents, pesticides, heavy metals, mycotoxins and microbial counts, each compared against a limit. A product can be potent and still impure, or pure and low in potency.

Purity is documented on a certificate of analysis from an accredited laboratory and is one half of the identity-and-purity requirement that Good Manufacturing Practice imposes on every ingredient. Consumers most often meet the word in isolate marketing, where it is sometimes conflated with quality; a pure isolate says nothing about the accuracy of the finished product's label claim or the cleanliness of the manufacturing environment.