Skip to content

Batch information on every product pageTHC < 0.3%Shipped from France10% off when you sign up

From the plant

CBLCannabicyclol

A degradation product of CBC formed by light or heat; a positive allosteric modulator of the 5-HT1A receptor in vitro.

Unscheduled
Level of detail

C₂₁H₃₀O₂

CAS 67920-00-7

Family
PhytocannabinoidMinor
Origin
Degradation product
First described
1964
Molar mass
314.46 g/mol

Updated on

In plain terms

CBL is not made by the plant: it forms when CBC is exposed to light or heat. In the laboratory it acts very little on the CB1 and CB2 receptors, but it strengthens the response of the serotonin 5-HT1A receptor. No human study has been published.

Receptors and activity

Target network

5-HT1APositive allosteric modulatorEC50 from 5 nM (serotonin 40 nM) to 1,480 nM (serotonin 175 nM), β-arrestin, human receptor; (±)-CBL, a single study (Haghdoost 2025)
  • Activates

The lower the cited value, the closer the target sits to CBL: one ring per factor of 100. A target with no measured value stays on the edge.

Where these targets live

Where each target has been found in humans, according to the cited studies. The map shows the target, not an effect of CBL.

Brain, side view
Body, front view
Blood

5-HT1A5-HT1A found in 6 regions of the body

  1. HippocampusdenseVery dense in the hippocampal CA1 field1
  2. BrainstemdenseHigh density in the raphe nuclei1
  3. CortexdenseDense in cortical layers I and II1
  4. AmygdaladenseHigh density in some amygdala nuclei1
  5. HypothalamuspresentIntermediate density, posterior hypothalamus1
  6. Spinal cordpresentPresent in the cervical spinal cord1

Map sources

  1. Pazos A et al. Serotonin receptors in the human brain--III. Autoradiographic mapping of serotonin-1 receptors. Neuroscience, 1987 (new tab)

Cited values

  1. 5-HT1APositive allosteric modulatorno measured value cited

    EC50 from 5 nM (serotonin 40 nM) to 1,480 nM (serotonin 175 nM), β-arrestin, human receptor; (±)-CBL, a single study (Haghdoost 2025)

Bar length follows the measured value (Ki, Kd, EC50 or IC50), on one scale shared by every entry, from 100 µM to 0.1 nM. A target with no cited value has no bar.

Measured effects

Not characterised. No placebo-controlled human trial has measured the effects of CBL, so no level is shown.

Levels computed from placebo-controlled human trials: difference from placebo on 100, at the dose and route stated. Read the method

Pharmacology

Cannabicyclol (CBL) was isolated from hashish by thin-layer chromatography by Korte and Sieper in 1964; first taken for a THC-type compound, its structure was established by Mechoulam and Gaoni in 1967, and its relative configuration by X-ray diffraction in 1970 (Radwan 2021; Haghdoost 2025). In 1968, Crombie et al. obtained it by irradiating cannabichromene (CBC): CBL has no enzymatic pathway and forms from CBC through a photochemical [2+2] cyclisation or under acidic conditions (Caprioglio 2022). Russo et al. (2008) identified it by gas chromatography in funerary cannabis about 2 700 years old. It has the same molecular formula as CBD and Δ9-THC (C₂₁H₃₀O₂, 314.46 g·mol⁻¹). Its pharmacology rests on a single in vitro study, carried out on synthetic (±)-CBL and funded by Charlotte's Web (Haghdoost 2025): no measurable binding at CB1, weak binding at CB2 at 10 µM and, at the human 5-HT1A receptor, weak agonism at high concentrations and positive allosteric modulation of the serotonin response (EC50 of 5 nM in the presence of 40 nM serotonin). An early evaluation in rhesus monkeys (Mechoulam 1970) found no intoxicating effect, but at a very low dose (5.5 µg/kg intravenously), which does not allow a conclusion (Haghdoost 2025). No human study has been published.

Key sources.

History

Source
Present in cannabis as a degradation product of CBC, formed by light or heat

Biosynthetic pathway

No enzymatic pathway: CBL forms from cannabichromene (CBC) through an intramolecular photochemical [2+2] cyclisation (Crombie 1968; Caprioglio 2022); acid treatment of CBC also produces it (Caprioglio 2022; Haghdoost 2025). The reaction keeps the configuration of the starting CBC and gives a single diastereomer (Haghdoost 2025). Because natural CBC is scalemic (Calcaterra 2023), CBL in the plant is not expected as a pure enantiomer; no measurement of its enantiomeric composition in cannabis was found.

Classification

Family, origin and source verification

Family

Phytocannabinoid › Minor

Presence in the plant

Artefact: formed by oxidation, light, heat or solvent

Chemistry

Type CBL · C5 side chain · neutral form

Verification

Every fact on this entry was checked against its primary sources on 20 October 2026.

Wikipedia (English)

Cannabicyclol (new tab)

Article paired by the molecule's structure (InChIKey), revision read on 19 October 2026. Read as a second opinion, never cited as a source.

References

  1. Crombie et al. 1968, Tetrahedron Lett: photochemical production of CBL from CBC (new tab)PMID 5697175
  2. Radwan et al. 2021, Molecules: CBL type (isolation 1964, structure 1967, X-ray 1970) (new tab)PMID 34066753
  3. Caprioglio et al. 2022, Biomolecules: cyclisation of CBC to CBL (light, acid) (new tab)PMID 36008978
  4. Haghdoost et al. 2025, J Nat Prod: CBL at CB1, CB2 and 5-HT1A receptors (funded by Charlotte's Web) (new tab)PMID 39811943
  5. Calcaterra et al. 2023, J Nat Prod: natural CBC is scalemic (new tab)PMID 37023389
  6. Russo et al. 2008, J Exp Bot: 2,700-year-old funerary cannabis (CBL identified) (new tab)PMID 19036842

Identifiers

Names

Common name
Cannabicyclol
IUPAC name
9,13,13-trimethyl-5-pentyl-8-oxatetracyclo[7.4.1.02,7.012,14]tetradeca-2,4,6-trien-3-ol
Other names
CBL

Identifiers

Formula
C₂₁H₃₀O₂
CAS
67920-00-7
PubChem CID
30607(new tab)
InChIKey
IGHTZQUIFGUJTG-UHFFFAOYSA-N
SMILES
CCCCCC1=CC(=C2C3C4C(C3(C)C)CCC4(OC2=C1)C)O

Machine-readable entry (JSON)

LLM ingestion format: a structured superset of the entry (identifiers, binding, versioned legal status). Full corpus.