Δ11-Tetrahydrocannabinol

Δ¹¹-Tetrahydrocannabinol (Delta-11-THC, exo-THC, Δ¹¹-THC, Δ⁹⁽¹¹⁾-THC, exo-Tetrahydrocannabinol) is a rare isomer of tetrahydrocannabinol (Δ⁹-THC), developed in the 1970s. It can be synthesised from Δ⁸-THC by several different routes,^[1][2][3] though only the (6aR, 10aR) enantiomer is known.

This article is about a rare synthetic isomer of THC. For common analogues mistakenly referred to as "delta-11", see 11-Hydroxy-THC and 11-Hydroxy-Δ-8-THC.

Δ¹¹-Tetrahydrocannabinol

Clinical data
Other names	Delta-11-THC, Exo-THC, Δ11-THC, Δ9(11)-THC, exo-Tetrahydrocannabinol
ATC code	None
Identifiers
IUPAC name (6aR,10aR)-6,6-dimethyl-9-methylidene-3-pentyl-7,8,10,10a-tetrahydro-6aH-benzo[c]chromen-1-ol
CAS Number	16849-44-8 27179-28-8
PubChem CID	167577
Chemical and physical data
Formula	C21H30O2
Molar mass	314.469 g·mol−1
3D model (JSmol)	Interactive image
SMILES CCCCCC1=CC(=C2[C@@H]3CC(=C)CC[C@H]3C(OC2=C1)(C)C)O
InChI InChI=1S/C21H30O2/c1-5-6-7-8-15-12-18(22)20-16-11-14(2)9-10-17(16)21(3,4)23-19(20)13-15/h12-13,16-17,22H,2,5-11H2,1,3-4H3/t16-,17-/m1/s1 Key:AOYYFUGUUIRBML-IAGOWNOFSA-N

In recent studies in 2022 it was found to "significantly reduce" the effects of Δ⁹-THC and has been suggested to act as a CB₁ receptor antagonist in humans, with the cited study showing "one partial success in the quest for an antagonist is the fact that D9,11-THC was found to significantly reduce the effect of D9-THC"^[4] and did not substitute for Δ⁹-THC in rhesus monkeys.^[5][6] It has been identified as a component of grey market vaping liquids sold for use in humans.^[7] Δ¹¹-THC has been identified as an impurity found in pharmaceutical dronabinol.^[8][9]

Legality

United States

As of now, Delta-11-THC is federally legal and uncontrolled, and faces no repercussions for possession unless in Arkansas or other states that prohibit intoxicating hemp-derived cannabinoids. However, Delta-11-THC, being an isomer and analogue of illicit Delta-9-THC means it can be persecuted under the Federal Analogue Act

Arkansas

As of June 25, 2025, the U.S. 8th Circuit Court of Appeals overturned a lower court's injunction, allowing Arkansas to enforce its ban on hemp-derived THC products, including Delta-11 THC. This ruling means that Act 629, which classifies Delta-8, Delta-9 (above 0.3%), and Delta-10 THC ("Psychoactive hemp-derived cannabinoids" as stated in Act 629) as Schedule VI controlled substances in the state, is now enforceable. Previously, sales of these products had been temporarily permitted due to the injunction.^[10][11]

Japan

Delta-11-THC falls under general THC restriction in Japan and is illegal to possess or use.

See also

• Abeo-HHC acetate
• Cis-THC
• Δ-3-Tetrahydrocannabinol
• Δ-4-Tetrahydrocannabinol
• Δ-7-Tetrahydrocannabinol
• Δ-10-Tetrahydrocannabinol
• Hexahydrocannabinol
• Iso-THC
• L-759,656