Concentration (of a product)

Concentration is the amount of a substance contained in a given quantity of product, most often expressed for cannabinoids as milligrams per milliliter or percent by weight.

A bottle labeled 1,000 milligrams of CBD in 30 milliliters has a concentration of about 33 milligrams per milliliter, which is the figure that determines how much is in each dropper or drop. Topicals and edibles are usually described by milligrams per container or per piece, and laboratory reports give percent weight by weight alongside milligrams per unit. Total content and concentration are easily confused: a larger bottle can hold more CBD while being less concentrated.

Laboratories measure concentration by chromatography and compare the result with the label claim, and regulators expect the two to agree within a stated tolerance. Because oils separate and cannabinoids slowly degrade, concentration can drift over shelf life, which is why testing is repeated during stability studies. The same word is used in medicine for the level of a drug in blood, as in maximum plasma concentration, and in psychology for sustained attention.