Δ9-cis-THC(-)-Δ9-cis-tetrahydrocannabinol
The cis diastereoisomer of Δ9-THC, present in fibre hemp; about 10-fold lower CB1 affinity.
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.
C₂₁H₃₀O₂
CAS 43009-38-7
- Family
- PhytocannabinoidMinor
- Origin
- Origin not established (debated)
- Molar mass
- 314.46 g/mol
Updated on
In plain terms
Δ9-cis-THC is a close relative of THC: same formula, same skeleton, but a different geometry where two rings join. It is found in fibre hemp, often at about half the level of ordinary THC. It activates the same receptors, about ten times more weakly, and no human study has been published.
Receptors and activity
Target network
- Activates
- Blocks or inhibits
The lower the cited value, the closer the target sits to Δ9-cis-THC: 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 Δ9-cis-THC.
CB1CB1 found in 7 regions of the body
- Basal gangliadenseMost dense in basal ganglia outflow nuclei1
- CerebellumdenseVery dense in the cerebellum1
- HippocampusdenseVery high concentrations in the hippocampus2
- AmygdaladenseHigh concentrations in the amygdala2
- CortexpresentPresent throughout the neocortex2
- Adipose tissuepresentExpressed in adipose tissue3
- GutpresentColonic epithelium, smooth muscle and plexus4
Map sources
- Herkenham M et al. Cannabinoid receptor localization in brain. Proc Natl Acad Sci U S A, 1990 (new tab)
- 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)
- Engeli S et al. Activation of the peripheral endocannabinoid system in human obesity. Diabetes, 2005 (new tab)
- Wright K et al. Differential expression of cannabinoid receptors in the human colon: cannabinoids promote epithelial wound healing. Gastroenterology, 2005 (new tab)
Cited values
- CB1Partial agonistKi = 228 nM · human44 out of 100
Schafroth et al. 2021, J Nat Prod (new tab) · [3H]CP55940 displacement, CHO-hCB1 membranes; EC50 [35S]GTPγS 552 nM (partial agonist vs CP55940)
- CB2Partial agonistKi = 99 nM · human50 out of 100
Schafroth et al. 2021, J Nat Prod (new tab) · [3H]CP55940 displacement, CHO-hCB2 membranes; EC50 [35S]GTPγS 119 nM (partial agonist)
- ABHD12InhibitorIC50 = 14.1 µM · human14 out of 100
Schafroth et al. 2021, J Nat Prod (new tab) · in vitro enzyme inhibition; judged to be of no consequence at the concentrations reached in vivo
- FAAHInhibitorIC50 = 36.3 µM · human7 out of 100
Schafroth et al. 2021, J Nat Prod (new tab) · in vitro enzyme inhibition; judged to be of no consequence at the concentrations reached in vivo
Pharmacology
Δ9-cis-THC is the diastereoisomer of Δ9-trans-THC: the ring junction is cis, with the 6aS,10aR configuration for the major enantiomer. Schafroth et al. (2021) measured it in European fibre hemp varieties at about half the level of Δ9-trans-THC (mean trans/cis ratio of about 2:1, rising to 14:1 and 61:1 in two THC-rich samples), while it was undetectable in a THC-rich medicinal cannabis (Bedrocan). The natural product is scalemic, with an enantiomeric purity of about 80 to 90 % (enantiomeric excess of 79.8 % in one sample). At human receptors expressed in CHO cells, the (−) enantiomer binds CB1 with a Ki of 228 nM and CB2 with a Ki of 99 nM, against 22 and 47 nM for Δ9-trans-THC, and behaves as a partial agonist in the [35S]GTPγS assay; the (+) enantiomer is almost inactive. In BALB/c mice, it produced the full cannabinoid tetrad at 50 mg/kg intraperitoneally, against 6 to 10 mg/kg for Δ9-trans-THC. Older work had found the racemate inactive in behavioural tests in rhesus monkeys (1971) and the (+) enantiomer about 100 times less potent in dogs (1981). No human data exist: no pharmacokinetics, no metabolism, no subjective effects.
Key sources.
- Schafroth MA, Mazzoccanti G, Reynoso-Moreno I, et al. Δ9-cis-Tetrahydrocannabinol: Natural Occurrence, Chirality, and Pharmacology. J Nat Prod. 2021;84(9):2502-2510 (full text CC-BY: ETH Research Collection) (new tab)PMID 34304557
- Radwan et al. 2021, Molecules: inventory, isolation by Smith & Kempfert 1977 (new tab)PMID 34066753
- INCB, Green List (35th ed., 2024): Δ9-THC and its stereochemical variants, Schedule II of 1971 (new tab)
- ANSM, consolidated list of narcotics (26/06/2026) (new tab)
- PubChem CID 12831993, (−)-Δ9-cis-THC (identifiers, InChIKey, CAS) (new tab)
History
- Source
- Plant (fibre hemp); mode of formation not established
Biosynthetic pathway
Not established. Because the natural compound is scalemic, Schafroth et al. (2021) propose either a poorly stereoselective oxidocyclase activity, like the one forming CBD and Δ9-trans-THC, or a pericyclic cyclisation from CBGA, like the one leading to CBC. No enzyme has been identified.
Legal framework
- European Union
Internationally controlled as a stereochemical variant of Δ9-THC, listed in Schedule II of the 1971 Convention (INCB Green List, 35th edition, 2024). Schafroth et al. (2021) argue that the legal criterion "Δ9-THC and isomers" separating hemp from cannabis should be revised or made more precise: two fibre hemp varieties (CRA_5 Fibranova and Kompolti) would exceed the 0.3 % threshold if the cis isomer were counted.
- France
Covered without being named: it falls under the generic entry "tetrahydrocannabinols, their esters, ethers, salts" (arrêté of 22 February 1990, annex III of the ANSM consolidated list of 26/06/2026) and under the generic benzo[c]chromene class (ANSM decisions of 22/05/2024 and 03/06/2024). Checked on 19/10/2026.
Sources: EUR-Lex, UNODC, CND, ANSM, IUPHAR/BPS, ChEBI, EUDA. Our method.
Classification
Family, origin and source verification
- Family
Phytocannabinoid › Minor
- Presence in the plant
Present in the plant; origin not established
Sources disagree on this point.
- Chemistry
Type divers (Radwan 2021) · C5 side chain · neutral form
- Verification
Every fact on this entry was checked against its primary sources on 20 October 2026.
- Wikipedia (English)
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
- Schafroth MA, Mazzoccanti G, Reynoso-Moreno I, et al. Δ9-cis-Tetrahydrocannabinol: Natural Occurrence, Chirality, and Pharmacology. J Nat Prod. 2021;84(9):2502-2510 (full text CC-BY: ETH Research Collection) (new tab)PMID 34304557
- Radwan et al. 2021, Molecules: inventory, isolation by Smith & Kempfert 1977 (new tab)PMID 34066753
- INCB, Green List (35th ed., 2024): Δ9-THC and its stereochemical variants, Schedule II of 1971 (new tab)
- ANSM, consolidated list of narcotics (26/06/2026) (new tab)
- PubChem CID 12831993, (−)-Δ9-cis-THC (identifiers, InChIKey, CAS) (new tab)
Identifiers
Names
- Common name
- (-)-Δ9-cis-tetrahydrocannabinol
- IUPAC name
- (6aS,10aR)-6,6,9-trimethyl-3-pentyl-6a,7,8,10a-tetrahydrobenzo[c]chromen-1-ol
- Other names
- (-)-delta-9-cis-tetrahydrocannabinol · cis-THC · Δ9-cis-THC · (6aS,10aR)-6,6,9-trimethyl-3-pentyl-6a,7,8,10a-tetrahydrobenzo[c]chromen-1-ol · CHEMBL4845760
Identifiers
- Formula
- C₂₁H₃₀O₂
- CAS
- 43009-38-7
- PubChem CID
- 12831993(new tab)
- InChIKey
- CYQFCXCEBYINGO-SJORKVTESA-N
- SMILES
- CCCCCC1=
CC2= C([C@@H] 3C= C(CC[C@@H] 3C(O2) (C) C) C) C(= C1) O
LLM ingestion format: a structured superset of the entry (identifiers, binding, versioned legal status). Full corpus.