Cannabinoids are unique, odorless chemical compounds produced in cannabis plants that may aid in the plants' success and help the plants to combat competitors, predators, and pathogens. The term cannabinoid technically refers to the structurally homogenous class of terpenes, compounds with partial terpene structure, produced in Cannabis sativa. All cannabinoids are assumed to originate from acidic cannabinoid forms, with CBGA suspected as the precursor of all other cannabinoids.
Of the chemical compounds generally referred to as cannabinoids, only Delta 9 THC, Delta 8 THC, and CBN are known to bind to cannabinoid receptors located throughout the body. The binding of cannabinoids to cannabinoid receptors can induce a variety of physiological processes, such as effects on appetite, pain-sensation, mood, and memory. For this reason, it can be useful to calculate a product's total THC, expressed as
Total THC = Delta 9 THC + (0.877 × Delta 9 THCA).
The calculation of total THC accounts for the loss of mass when tetrahydrocannabinolic acid (THCA), the acidic version of Delta 9 THC, is converted into Delta 9 THC when cannabis is heated before ingestion. In further explanation, cannabinoids in their acidic cannabinoid forms are not psychotropic in and of themselves, and must undergo decarboxylation to produce any derivative compounds that are psychoactive. Acidic cannabinoids do not decarboxylate under normal conditions, however, exposure to heat, light, and air appears to cause the major cannabis constituents to degrade into a wide array of minor cannabinoids, some of which are psychoactive. For this reason, it is useful to measure the various cannabinoids that may be present in a cannabis product and quantify the total amount of cannabinoids and THC that someone can expect to consume.