Hexahydrocannabinol (HHC)

(6aR,10aR)-6,6,9-trimethyl-3-pentyl-6a,7,8,9,10,10a-hexahydrobenzo[c]chromen-1-ol

Overview

Hexahydrocannabinol (HHC) belongs to Cannabinoids.

Key safety note: HHC is intoxicating and impairing much like THC: it slows coordination and reaction time (impairing driving) and can cause anxiety, panic, rapid heart rate and nausea, and, as with high-potency THC, acute psychosis in susceptible people, which has been documented in HHC users.[5][2]
Effects
Subjective effects vary. What a substance feels like depends on dose, individual physiology, mindset, and setting. The points below describe commonly reported effects, not guaranteed, uniform, or desirable outcomes.
  • Broadly THC-like: euphoria, relaxation, giddiness, altered perception of time, music and surroundings, and increased appetite. Users often describe it as somewhat milder or more 'functional' than Δ⁹-THC, though this varies with the product and epimer ratio.
  • Unwanted effects mirror cannabis: dry mouth, red eyes, increased heart rate, dizziness, impaired coordination and short-term memory, and, especially at high doses, anxiety, paranoia or panic.
  • When vaped, effects begin within minutes and last roughly 2–4 hours. Taken orally (edibles) the onset is delayed (30–90 minutes) and effects last considerably longer, as with THC edibles.
Dosing & duration
Harm-reduction note: These are commonly cited reference ranges, not a recommendation or a “safe” dose. Potency, purity, body chemistry, tolerance, and drug combinations vary widely. Start low, go slow, wait for full effects before redosing, and never assume an unknown product matches these figures. Missing data is not evidence of safety.

Most commonly vaped/inhaled (vape pens, e-liquid) or eaten (gummies/edibles). Also smoked as infused flower.. There is no reliable dosing standard for HHC. Commercial products are unregulated mixtures of the more-active (9R) and much-weaker (9S) epimers in undisclosed, variable amounts, so two products labelled the same can differ greatly in strength, and vaped doses in particular cannot be measured meaningfully. The oral figures below are rough PsychonautWiki reference ranges for relatively pure HHC, NOT a recommendation or a 'safe' dose. As with THC edibles, start very low, wait the full delayed onset (up to 1.5–2 hours) before considering more, and do not drive.

Dose ranges

Threshold

< 5 mg (oral)

Light

5–12 mg (oral)

Common

12–30 mg (oral)

Strong

30–60 mg (oral)

Heavy

60 mg + (oral)

Duration

onset

Vaped: within minutes, oral: 30–90 minutes

total

Vaped ≈2–4 hours, oral considerably longer (THC-edible-like)

after effects

Possible grogginess or 'hangover'. Tolerance with regular use

Chemical & Physical Properties
FormulaC21H32O2
Molar mass316.5 g/mol
StateNot reported
Melting pointNot reported
Boiling pointNot reported
DensityNot reported
Vapor pressureNot reported
pKaNot reported
LogP7.8 (predicted, XLogP3)
SolubilityNot reported
Refractive indexNot reported
Identifiers & Synonyms
CASNot reported
CAS (enantiomer)
PubChem CID16050328
InChIKeyXKRHRBJLCLXSGE-VNCLPFQGSA-N
InChIInChI=1S/C21H32O2/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/h12-14,16-17,22H,5-11H2,1-4H3/t14?,16-,17-/m1/s1
SMILESCCCCCC1=CC(=C2[C@@H]3CC(CC[C@H]3C(OC2=C1)(C)C)C)O

Synonyms

    Pharmacodynamics & Biochemistry

    HHC (hexahydrocannabinol) is a semi-synthetic cannabinoid: the hydrogenated form of THC, in which the cyclohexene-ring double bond of Δ⁹-THC is saturated. Removing that double bond makes HHC more chemically and thermally stable and more resistant to oxidation than THC, while leaving it pharmacologically THC-like. It is manufactured industrially from hemp-derived CBD (converted to THC, then hydrogenated) and reached the market around 2021–2022 as a 'legal' cannabis alternative. Like THC, HHC is an agonist at the cannabinoid CB1 and CB2 receptors. CB1 activation in the central nervous system produces the psychoactive 'high', euphoria, relaxation, altered perception of time and space, and appetite stimulation, while CB2 is mainly peripheral and immune. Most statements about HHC's effects are extrapolated from THC, because dedicated clinical pharmacology of HHC itself is still very limited. Hydrogenation creates a new stereocentre at C9, so HHC exists as two epimers: (9R)-HHC and (9S)-HHC. The (9R) epimer binds CB1 far more strongly and carries most of the activity, whereas (9S) is much weaker. Commercial HHC is an uncontrolled mixture of the two, so a product's potency depends on its epimer ratio. HHC is highly lipophilic and, like THC, is metabolised in the liver to hydroxylated metabolites and stored in fat, giving a variable and relatively long elimination. The two epimers are metabolised and excreted somewhat differently. Reliable quantitative receptor-affinity data for HHC are not established, so no binding table is shown.

    Biological targets

    • CB1
    • CB2
    Pharmacokinetics
    BioavailabilityNot established for HHC, inhaled cannabinoids are highly variable and oral absorption is low and erratic (extrapolated from THC)
    TmaxNot reported
    Half-lifeNot established in humans, expected long and variable (highly lipophilic, fat-stored, THC-like)
    VdNot reported
    Protein bindingNot reported
    MetabolismHepatic oxidation to hydroxylated metabolites. (9R)- and (9S)-HHC are metabolised and excreted somewhat differently
    ExcretionMetabolites in urine and faeces. Parent and metabolites detectable in blood, urine and oral fluid
    Toxicology & Safety
    Harm-reduction note: Toxicity and risk depend on dose, route, purity, combinations, setting, and individual health factors. Missing harms should never be interpreted as evidence of safety.

    Not reported

    HHC is intoxicating and impairing much like THC: it slows coordination and reaction time (impairing driving) and can cause anxiety, panic, rapid heart rate and nausea, and, as with high-potency THC, acute psychosis in susceptible people, which has been documented in HHC users. The larger, distinct hazard is that HHC is an unregulated product: vapes, gummies and other goods contain variable, often undisclosed amounts of an epimer mixture of unknown potency, may carry reaction by-products, residual hydrogenation catalysts (metals) or solvents, and are sometimes mislabelled or adulterated. Long-term safety data are essentially absent. Like THC it can produce tolerance and, with heavy regular use, dependence. Avoid driving or operating machinery, and note that combining it with alcohol or other depressants worsens impairment.[5][2]

    Legal Status
    Legal note: Legal status can change over time and may vary by country, region, formulation, analogue status, prescription context, and enforcement practice. Always confirm with current official sources before relying on this section.
    Interactions & Contraindications

    Drug interactions

    Alcohol Additive impairment, dizziness and sedation with alcohol and other CNS depressants.[2]
    Cannabis Additive psychoactive and cardiovascular effects with THC and other cannabinoids (tachycardia, anxiety).[2]
    Stimulants (amphetamines, cocaine) Caution with stimulants or drugs that raise heart rate and blood pressure, and in cardiovascular or psychiatric conditions (tachycardia, anxiety, psychosis).[5][2]
    Drugs cleared by shared CYP enzymes (e.g. CYP2C9, CYP3A4) As with other cannabinoids HHC may in theory interact with CYP-metabolised drugs, but specific data are lacking.[3]

    Contraindications

    Personal or family history of psychosis, schizophrenia or bipolar disorder history of psychosis, schizophrenia or bipolar disorder (cannabinoids can precipitate or worsen psychosis).[5]
    Pregnancy or breastfeeding[2]
    Cardiovascular disease, hypertension or arrhythmia tachycardia and blood-pressure effects.[2]
    Settings where impairment or dissociation risks injury (driving, water, heights) before driving or operating machinery, with caution combining with alcohol or other depressants.[2]
    Usage & Context
    • Sold since around 2021–2022 as a semi-synthetic 'legal high' cannabis substitute, in vapes, e-liquids, edibles (gummies), infused flower and hash, marketed to exploit gaps in cannabis law.
    • Used recreationally for cannabis-like effects, and sometimes in the hope of a THC-like high that evades standard THC drug tests, though HHC and its metabolites are increasingly detectable.
    • Its rapid spread across Europe and beyond made it one of the most prominent semi-synthetic cannabinoids monitored by drug agencies, prompting a wave of national bans.
    Sources & Evidence

    Further Information