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Synthetic

CP 55,940

The reference full CB1/CB2 agonist: tritium-labelled, it revealed the cannabinoid receptor in 1988.

Narcotic: named in schedule
Level of detail

Harm-reduction warning

No characterised human dose: animal / in vitro data only. Effect profile, safety margin and acute toxicity are not documented in human clinical practice. Extremely potent compound: severe effects, seizures and deaths reported in the literature.

C₂₄H₄₀O₃

CAS 83002-04-4

Family
Synthetic CB receptor agonistResearch ligand or medicine
Molar mass
376.60 g/mol

Updated on

In plain terms

CP 55,940 is a molecule created in the laboratory by Pfizer. It does not come from hemp and is found in no plant: it serves researchers as a reference tool, because it binds very strongly to the receptors of the endocannabinoid system, more than THC does. It is classified as a narcotic in France and is not a medicine.

Receptors and activity

Target network

CB1Agonistno measured value
  • Activates
  • Binds or modulates

The lower the cited value, the closer the target sits to CP 55,940: 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 CP 55,940.

Brain, side view
Body, front view
Blood

CB1CB1 found in 7 regions of the body

  1. Basal gangliadenseMost dense in basal ganglia outflow nuclei1
  2. CerebellumdenseVery dense in the cerebellum1
  3. HippocampusdenseVery high concentrations in the hippocampus2
  4. AmygdaladenseHigh concentrations in the amygdala2
  5. CortexpresentPresent throughout the neocortex2
  6. Adipose tissuepresentExpressed in adipose tissue3
  7. GutpresentColonic epithelium, smooth muscle and plexus4

Map sources

  1. Herkenham M et al. Cannabinoid receptor localization in brain. Proc Natl Acad Sci U S A, 1990 (new tab)
  2. Glass M et al. Cannabinoid receptors in the human brain: a detailed anatomical and quantitative autoradiographic study in the fetal, neonatal and adult human brain. Neuroscience, 1997 (new tab)
  3. Engeli S et al. Activation of the peripheral endocannabinoid system in human obesity. Diabetes, 2005 (new tab)
  4. Wright K et al. Differential expression of cannabinoid receptors in the human colon: cannabinoids promote epithelial wound healing. Gastroenterology, 2005 (new tab)

Cited values

  1. CB1Agonistno measured value cited
  2. CB2Agonistno measured value cited
  3. GPR55Modulatorno measured value cited
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.

Pharmacology

CP 55,940 is a so-called nonclassical cannabinoid: the pyran ring of THC is open, leaving a phenol linked by a single bond to a hydroxylated cyclohexane, with a branched 1,1-dimethylheptyl chain and a 3-hydroxypropyl arm. It is a full, non-selective agonist of CB1 and CB2, with affinity constants of 0.5 to 5.0 nM at CB1 and 0.69 to 2.8 nM at CB2 (Pertwee et al. 2010), and it acts as a full agonist where Δ9-THC is partial (Fantegrossi et al. 2014, about synthetic cannabinoids in general). Its distinction lies less in its pharmacology than in its historical role: labelled with tritium, it allowed Devane et al. to characterise a cannabinoid receptor in rat brain in 1988, then Herkenham et al. to map its distribution in 1990. At the GPR55 receptor, published results contradict each other, between an activation (Ryberg et al. 2007) and an antagonist or partial agonist effect (Kapur et al. 2009). No clinical study or human pharmacokinetics was found in the sources consulted; what is known of its toxicity comes from cell culture and animals.

Key sources.

History

Source
A wholly synthetic molecule, designed in Pfizer's laboratories. It occurs neither in hemp nor in any other known plant, and no living organism produces it. Before the appearance, around 2004, of smoking blends containing synthetic cannabinoids, CP-55,940 and WIN-55,212-2 were among the few synthetic cannabinoids available in small quantities for pharmacological research (UNODC, Tettey et al. 2021).

Origin

Laboratory synthesis

No known biosynthetic pathway: CP 55,940 results from no plant or animal metabolism. It is a so-called non-classical cannabinoid, obtained by total synthesis within a series of bicyclic compounds explored by Pfizer. Compared with THC, the pyran ring is opened, the pentyl chain is replaced by a branched chain of the 1,1-dimethylheptyl type, and a 3-hydroxypropyl arm is grafted onto the cyclohexane ring, which additionally bears a further alcohol function.

Classification

Family, origin and source verification

Family

Synthetic CB receptor agonist › Research ligand or medicine

Class

non-classical

Verification

Classification, sources and binding values checked on 20 October 2026; text read against its sources and Wikipedia.

Wikipedia (English)

CP 55,940 (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. Melvin et al., J Med Chem 1984: A cannabinoid derived prototypical analgesic (new tab)PMID 6690685
  2. Devane et al., Mol Pharmacol 1988: rat brain cannabinoid receptor (new tab)PMID 2848184
  3. Herkenham et al., Proc Natl Acad Sci USA 1990: localisation of the cannabinoid receptor in the brain (new tab)PMID 2308954
  4. Pertwee et al., Pharmacol Rev 2010 (IUPHAR): classification and affinities of cannabinoid ligands (new tab)PMID 21079038
  5. Ryberg et al., Br J Pharmacol 2007: GPR55 bound and activated by CP55940 (new tab)PMID 17876302
  6. Kapur et al., J Biol Chem 2009: atypical response of GPR55 to cannabinoid ligands (new tab)PMID 19723626
  7. Fantegrossi et al., Life Sci 2014: pharmacology of K2-type synthetic cannabinoids (new tab)PMID 24084047
  8. Tomiyama & Funada, Arch Toxicol 2021: muscle cell apoptosis via CB1 (new tab)PMID 33174160
  9. Leishman et al., Front Mol Neurosci 2018: effects of CP 55,940 on the mouse brain lipidome (new tab)
  10. Tettey et al., UNODC, Forensic Sci Int Synerg 2021: analytical methods for cannabinoid agonists (new tab)PMID 33665591
  11. PubChem, compound CID 104895 (CP 55,940) (new tab)
  12. ANSM, consolidated list of substances classified as narcotics, updated 16/02/2026 (annex IV, Cyclohexylphenols) (new tab)

Identifiers

Names

IUPAC name
2-[(1R,2R,5R)-5-hydroxy-2-(3-hydroxypropyl)cyclohexyl]-5-(2-methyloctan-2-yl)phenol
Other names
CP55940 · CP-55940 · CP-55,940 · CP55,940 · CP 55940

Identifiers

Formula
C₂₄H₄₀O₃
CAS
83002-04-4
PubChem CID
104895(new tab)
InChIKey
YNZFFALZMRAPHQ-SYYKKAFVSA-N
SMILES
CCCCCCC(C)(C)C1=CC(=C(C=C1)[C@@H]2C[C@@H](CC[C@H]2CCCO)O)O

Machine-readable entry (JSON)

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