THC oxidation

THC oxidation is the chemical reaction in which tetrahydrocannabinol reacts with oxygen and loses hydrogen, converting over time into cannabinol, a mildly active cannabinoid.

The reaction happens spontaneously in stored plant material and extracts and is accelerated by heat, light and exposure to air, so the CBN content of a sample is a rough indicator of its age and storage conditions. THC acid first decarboxylates to THC, which then oxidizes to CBN; CBN is thus not made by the plant in any quantity but appears as a breakdown product. CBN binds cannabinoid receptors much more weakly than THC, which is why old cannabis is generally less intoxicating.

For hemp products the reaction matters in two ways. It changes the cannabinoid profile over shelf life, which stability testing tracks, and it means a product formulated with a stated CBN content may owe that CBN either to deliberate conversion from THC or to isolation. Regulators count only delta-9 THC and THCA toward the legal limit, so oxidation does not raise a product's THC. CBN has been studied for sleep in a few small early trials, without established findings.