Cannabicyclol (CBL)

Cannabicyclol (CBL) is a compound found in cannabis. Many describe the substance as a phytocannabinoid even though CBL is void of activity at cannabinoid receptors. Defining the molecule as a cannabinoid involves a chemical view rather than a pharmacological interpretation.

Defining CBL as a cannabinoid

From a drug standpoint, the receptor targeted by the ingredient is crucial for definition. Yet there is a different method of defining cannabinoid activity without changing the word ‘cannabinoid’. Regarding chemistry, CBL comes from the degradation of a different cannabinoid — cannabichromene (CBC.)

Both compounds are not, however, naturally produced by cannabis. CBL is a photochemical derived from CBC. And cannabigerolic acid (CBGa) degrades into CBC.

And CBC and CBG are both CB2 receptor agonists and cannabinoids according to the molecular structure and natural origin. Therefore, relatives of CBGa — including inactive compounds such as cannabicyclol — are cannabinoids, too.

CBL (Cannabicyclol.)

Cannabicycol (CBL) chemistry

CBL only occurs when CBC reacts with UV light, heat, or oxidizes. Cannabicyclol is free of double bonds in its left ring. Moreover, two conjugated rings comprise the molecule — a tetrahydropyran and a benzene ring. This means cannabicyclol is a bicyclic compound.

Importantly, CBL only has one hydroxyl group located on the molecule’s southern position. Hydroxyl groups are crucial components that allow THC, for example, to bind the CB1 receptor’s orthostatic site.

Cannabinoids to a pharmacist

The lack of activity can be adressed with the lack of a suffix. International Non-proprietary Names (INNs) are used to define pharmacological activity in a clinical setting. And the suffix nab already defines cannabinoid receptor activity.

Pharmaceutical companies used the suffix nab, derived from the INN system, for synthetics such as nabilone. But the suffix also defines phytocannabinoids in the official language. In conclusion, cannabicyclol is a cannabinoid, but not a known cannabinoid-nab such as cannabinol.

The literature poorly documents CBL, (1) with little information recorded on the phytocannabinoid’s effects. More research is still needed to assess the role this cannabinoid has with human health.


  1. Morales P, Hurst DP, Reggio PH. Molecular Targets of the Phytocannabinoids: A Complex Picture. Prog Chem Org Nat Prod. 2017;103:103-131. doi:10.1007/978-3-319-45541-9_4