HHCHexahydrocannabinol

Aliases.Hexahydrocannabinol · 9R/9S-HHC

The first semi-synthetic cannabinoid placed under international control (UN 1971-II, 6 Dec 2025).

Updated on 1 May 2026

Level of detail

Identifiers

Formula: C₂₁H₃₂O₂
CAS: 6692-85-9
PubChem CID: 522237
First described: 1947 (Adams) · réémergence 2022
Origin: Semi-synthetic

In plain terms

HHC is a saturated cousin of THC created in the laboratory from CBD. More stable than THC, it saw a commercial wave in Europe in 2022 - then was placed under international control in December 2025. It is no longer marketed.

Receptors and activity

CB1 (9R)
Partial agonist
CB1 (9S)
Partial agonist
CB2
Partial 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
65
Appetite
70
High
80

Editorial estimate, not clinical.

Pharmacology

First synthesised by Roger Adams in 1947 but remaining obscure until its commercial re-emergence in 2022 in European laboratories, HHC became within three years one of the most closely watched cannabinoids in the world. Its structure no longer contains the double bond of THC - it is saturated by hydrogenation, which makes it more stable to heat and light, but does not remove its psychoactive effect. The two epimers (9R)-HHC and (9S)-HHC coexist in commercial products in variable proportions, with different CB1 affinities - this is why titration and batch purity are critical. Listed in Schedule II of the 1971 Convention by decision CND 68/5 of 12 March 2025, in force on 6 December 2025: the first semi-synthetic cannabinoid placed under international control. Phytogrammes no longer markets it since the scheduling came into force.