Δ8-THCDelta-8-tetrahydrocannabinol

Aliases.Delta-8-THC · Δ8-tétrahydrocannabinol

An isomer of Δ9-THC - about two thirds of its potency, reported as less anxiogenic. Covered by the THC-isomer clauses in the EU.

Updated on 1 May 2026

Level of detail

Identifiers

Formula: C₂₁H₃₀O₂
CAS: 5957-75-5
PubChem CID: 638026
First described: 1965 (Mechoulam et al.)
Origin: Plant (trace amounts) or semi-synthetic by isomerisation of CBD

In plain terms

Δ8-THC is a cousin of Δ9-THC: the double bond is simply shifted by one carbon. The result: about two thirds of the potency, often perceived as less anxiogenic. Legally treated as THC in most EU countries.

Receptors and activity

CB1
Partial agonist
CB2
Partial agonist
GPR55
Agonist

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
55
Clarity
40
Sleep
60
Appetite
75
High
75

Editorial estimate, not clinical.

Pharmacology

Δ8-THC is the best-known positional isomer of Δ9-THC: the double bond of the cyclohexene ring is simply shifted from carbon 9 to carbon 8, which is enough to alter the pharmacology markedly. CB1 affinity is about half as high (Ki ≈ 44–78 nM depending on the study - Pertwee 2008, Radwan 2015), and the subjective efficacy is reported as less anxiogenic and less paranoia-inducing than Δ9-THC at an equivalent dose, but with a comparable onset and duration. Hollister & Gillespie (1973) characterised its profile in humans - one of the few THC-like compounds with published human PK/PD data: 20–40 mg orally, about two thirds of the subjective potency of Δ9-THC. Naturally present in trace amounts (< 1 % of total cannabinoid content); commercial volumes come almost exclusively from acid isomerisation of CBD, which raises questions of purity (Δ10-THC, Δ6a,10a-THC by-products, and so on). Legally treated as THC in most European jurisdictions through the "isomers" clauses of the national annexes.