Cannabinoid degradation

Cannabinoid degradation is the gradual chemical breakdown of cannabinoids in a product over time, driven mainly by heat, light, oxygen and, for the acid forms, decarboxylation.

The best-known pathway is the oxidation of THC to cannabinol, which is why aged cannabis contains more CBN and less THC. CBD is more stable but slowly declines in warm, bright or air-exposed conditions and can, in acidic environments, convert in small amounts to other compounds. Acid forms such as CBDA lose their carboxyl group with heat and time, changing the cannabinoid profile even if total content stays similar. The carrier matters too, since some oils oxidize faster than others and can accelerate change.

Manufacturers study degradation through stability testing, in which samples are stored under defined conditions and re-tested at intervals, and the results set the shelf life and the best-by date on the label. Some products include an overage, a small amount above the label claim, to allow for expected loss. Dark glass, tight caps, cool storage and keeping products out of sunlight slow the process. A certificate of analysis reflects content on the day of testing, not at the end of shelf life.