CBLCannabicyclol

Aliases.CBL · Cannabicyclol

A UV degradation product of CBC. A marker of the age / oxidation of flower.

Updated on 1 May 2026

Level of detail

Identifiers

Formula: C₂₁H₃₀O₂
Molar mass: 314.46 g·mol⁻¹
CAS: 21366-63-2
PubChem CID: 59444380
First described: 1964
Origin: Plant (photochemical product)
InChIKey: IGHTZQUIFGUJTG-QSMXQIJUSA-N

In plain terms

CBL is what forms when sunlight degrades CBC in the flower. It is an oxidation marker: its presence indicates poorly stored or old flower.

Receptors and activity

CB1
Modulator
CB2
Modulator

Agonist
Partial agonist
Antagonist
Modulator
Inverse agonist

Hover over a row for the precise value (Ki, EC50…)

Subjective signature

Hover over an axis to read its definition.

Calm
20
Clarity
25
Sleep
15
Appetite
10
High
5

Editorial estimate, not clinical.

Pharmacology

CBL (cannabicyclol) was described by Korte & Sieper (1964) and then structurally characterised by Crombie & Ponsford (1968). There is no enzymatic biosynthesis: it is a product of photo-induced [2+2] cyclisation of CBC under UV light. Practically absent from fresh plant material, it accumulates in aged and poorly stored flower (an oxidation marker). Pharmacology: negligible CB1/CB2 activity, no psychotropic effect reported. Caprioglio et al. (Biomolecules 2022, PMID 36008978) place it within the "dark cannabinome". Its molar mass is identical to that of CBD (314.46 g·mol⁻¹) and so is its molecular formula, C₂₁H₃₀O₂, but its cyclic skeleton distinguishes it unambiguously in chromatography (HPLC, GC-MS). In practice, a high CBL level in an extract signals advanced photochemical degradation of the source plant material.

Key sources.