Tetrahydrocannabihexol

# Research Output: Tetrahydrocannabihexol (Δ9-THCH)

**PSX ID:** PSX-0348  
**Research Date:** 2026-05-12  
**Substance Readiness Assessment:** Sparse/Emerging — primary literature limited; significant reliance on forensic/toxicological papers and class-inference from THC homolog SAR data.

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## Chemical Identity

**Verified from PubChem CID 161906 [Ref 1, PubChem]:**

| Property | Value |
|---|---|
| IUPAC Name | (6aR,10aR)-3-hexyl-6,6,9-trimethyl-6a,7,8,10a-tetrahydrobenzo[c]chromen-1-ol |
| Molecular Formula | C₂₂H₃₂O₂ |
| Molecular Weight | 328.5 g/mol |
| CAS Registry Number | 36482-24-3 |
| PubChem CID | 161906 |
| InChIKey | DMJVNNFBMZZLFB-QZTJIDSGSA-N |
| Isomeric SMILES | CCCCCCC1=CC(=C2[C@@H]3C=C(CC[C@H]3C(OC2=C1)(C)C)C)O |

**Alternate names:** Δ9-Parahexyl; n-Hexyl-Δ9-THC; THC-H; THCh

**Chemical class:** Dibenzopyran (benzochromene) cannabinoid; terpenophenolic compound

**Homologous series position:** THCH bears a hexyl (6-carbon) alkyl side chain at C-3, placing it between Δ9-THCB (4-carbon; butyl), Δ9-THC (5-carbon; pentyl), and Δ9-THCP (7-carbon; heptyl). The side chain extension is the sole structural modification relative to Δ9-THC (Linciano et al. 2020 [Ref 1]).

**Δ8-THCH isomer:** A corresponding Δ8 isomer (JWH-124; CAS 20622-30-4) exists and is detectable in commercial products alongside Δ9-THCH. Both isomers have been detected in Japanese online market products (Tanaka & Kikura-Hanajiri 2024 [Ref 4]). This research output focuses on the Δ9 form unless otherwise noted.

**Seed data discrepancies:** The brief contained no SMILES, molecular formula, molecular weight, InChIKey, or PubChem CID. All chemical identity data was absent from the DB record and has been sourced from PubChem CID 161906 (verified via API) and the primary discovery paper (Linciano et al. 2020 [Ref 1]).

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## Pharmacology

### Receptor Pharmacology

**CB1 receptor — primary target:**  
THCH acts as a full agonist at the cannabinoid CB1 receptor. In a β-arrestin2 recruitment bioassay covering 30 THC isomers, homologs, and analogs, Janssens et al. (2024 [Ref 2]) identified THCH as one of multiple THC homologs showing higher potential for CB1 activation than Δ9-THC, based on either higher efficacy (Emax) or higher potency (EC50). The paper assessed compounds from picomolar to micromolar concentrations. **FLAG FOR REVIEW:** Specific EC50 or Ki values for THCH were not extractable from the abstract; the full paper (paywall-restricted) was not accessible. No published Ki or EC50 values for THCH at CB1 were found in the searchable literature.

**Comparative CB1 affinity context from structurally related homologs:**  
The same Italian research group (Citti, Cannazza et al.) established that THCP (7-carbon chain) binds human CB1 with Ki = 1.2 nM, comparable to CP55940 (Ki = 0.9 nM, a potent full agonist), and approximately 33× more potent than Δ9-THC at CB1 (Citti et al. 2019 [Ref 14]). THCB (4-carbon chain) has a reported Ki of approximately 15 nM at CB1. Given the documented monotonic potency increase with chain elongation in the cannabinoid homologous series — a finding confirmed across multiple structure-activity relationship studies (Bow & Rimoldi 2016 [Ref 13]; Martin et al. 1999 [Ref 11]) — THCH's hexyl chain is expected to place it between Δ9-THC and THCP in binding affinity. **FLAG FOR REVIEW:** This is class-inference. No published Ki data specific to THCH was found.

**CB1 structure-activity rationale:**  
The alkyl side chain at C-3 is the primary determinant of CB1 potency in classical cannabinoids. Chain elongation from 5 to 6 carbons (THC to THCH) increases lipophilicity and hydrophobic pocket engagement at the CB1 receptor (Bow & Rimoldi 2016 [Ref 13]). Martin et al. (1999 [Ref 11]) demonstrated that chain length and flexibility are critical for efficacy; short chains reduce potency while extended chains (up to 7–8 carbons) generally enhance it.

**CB2 receptor:**  
No published data specific to THCH at CB2. Class inference suggests CB2 activity analogous to Δ9-THC, which typically shows lower affinity at CB2 than CB1. CB1/CB2 selectivity ratios for THC homologs generally decrease (less CB1-selective) with chain extension (Bow & Rimoldi 2016 [Ref 13]). **FLAG FOR REVIEW:** CB2 data is inference only.

**Signal transduction:**  
As a full CB1 agonist, THCH is expected to signal via Gi/o-coupled pathways (cAMP inhibition, MAPK activation) and β-arrestin2 recruitment, as established for the homologous series (Raïch et al. 2021 [Ref 20]; Janssens et al. 2024 [Ref 2]).

### Pharmacokinetics

**Human PK data:** None published for THCH as of the research date. No controlled human pharmacokinetic studies identified.

**Mouse metabolism (primary animal data):**  
Brown & Harvey (1988 [Ref 10]) synthesized n-hexyl-Δ8-THC and n-hexyl-Δ9-THC (i.e., Δ8-THCH and Δ9-THCH) and administered them intraperitoneally to male Charles-River CD-1 mice. Key findings:

- **Δ9-THCH:** 16 hepatic metabolites identified; **Δ8-THCH:** 11 metabolites
- **Primary metabolic pathway:** Hydroxylation and oxidation at C-11 (analogous to the major Δ9-THC pathway producing 11-OH-THC and 11-nor-9-carboxy-THC)
- **Chain-length metabolic trend:** Compared to the pentyl homolog (Δ9-THC), there is a trend toward more hydroxy metabolites at the expense of carboxylic acids — reflecting the general reduction of terminal oxidation as chain length increases
- **Dihydroxy metabolites:** Present in low concentration in THCH but not typically observed with shorter homologs; become major metabolites in the heptyl homolog (THCP)
- **Route of isolation:** Solvent extraction and Sephadex LH-20 chromatography; metabolites identified by GC/MS

**CYP enzyme inference:**  
By analogy with Δ9-THC (where CYP2C9 is the dominant hydroxylase for C-11 oxidation, with contributions from CYP3A4 and CYP2C19), THCH is expected to undergo similar CYP-mediated metabolism. The extended alkyl chain may alter the relative CYP2C9 vs CYP3A4 contributions. **FLAG FOR REVIEW:** CYP data is class inference; no THCH-specific CYP studies found.

**Detectability in biological matrices:**  
A validated LC-MS/MS method (Muir et al. 2025 [Ref 3]) can qualitatively identify Δ8-THCH in urine and quantitatively confirm it in blood, with an LOD of 1 ng/mL for parent compounds. Δ9-THCH is also detectable in blood. A rapid LC-QTOF-MS screening method (Schirmer et al. 2025 [Ref 21]) validated for 24 semi-synthetic cannabinoids in blood (LOD 0.8–16 ng/mL) includes THCH among analytes. Standard immunoassay (ELISA) cross-reactivity for extended-chain THC homologs is reduced relative to Δ9-THC (Patton et al. 2024 [Ref 15]).

**Bioavailability and ROA:** No published human data. Common consumer ROAs are inhalation (vaping) and oral ingestion, consistent with other cannabinoids. Cayman Chemical reference material confirms the compound is available in research-grade form (Δ9-THCH, CAS 36482-24-3, Cayman Cat. 34186).

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## History

### Pre-discovery History (Parahexyl / Synhexyl)

The compound now called Δ9-THCH was synthesized decades before its identification in natural cannabis. Roger Adams and his group at the University of Illinois first synthesized **parahexyl** (also called synhexyl; n-hexyl-Δ³-THC) in approximately **1941–1942** during systematic efforts to determine the active principles of cannabis. Adams' work on THC homologs was published in the *Journal of the American Chemical Society* in 1949 ("New Analogs of Tetrahydrocannabinol. XIX"). Pharmacologist S. Loewe conducted early in vivo pharmacological testing in 1946, establishing that parahexyl induced catalepsy and motor incoordination in mice, mirroring effects of natural THC isolates. The compound was thus known as a synthetic cannabinoid isomer/analog prior to its identification as a natural product.

### Natural Isolation (2020)

Linciano et al. (2020 [Ref 1]) — a team at the University of Modena and Reggio Emilia led by Cinzia Citti and Giuseppe Cannazza — reported the first isolation and structural characterisation of Δ9-THCH from the **FM2 medicinal cannabis variety**. The same paper also described the concurrent isolation of its CBD analog, cannabidihexol (CBDH). The discovery followed the same group's 2019 identification of Δ9-THCP (heptyl chain) and Δ9-THCB (butyl chain) from the same variety (Citti et al. 2019 [Ref 14]).

Key findings of the discovery paper:
- The n-hexyl homologs fill the structural gap between the pentyl (Δ9-THC) and heptyl (Δ9-THCP) homologs
- Stereoselective synthesis of authentic standards was performed and used to confirm the natural product's identity by retention time, molecular ion, and fragmentation spectra matching
- Semi-quantification in FM2 cannabis was provided (very low abundance, consistent with other minor phytocannabinoids)
- CBDH was assessed for analgesic activity in mice and showed activity at low doses
- Δ9-THCH was distinguished from constitutional isomers: Δ9-THC monomethyl ether (Δ9-THCM; same molecular formula C₂₂H₃₂O₂) by chromatographic and spectroscopic means; no Δ9-THCM was detected in the variety studied

### Appearance on Recreational Markets

By 2021–2022, products claiming to contain Δ9-THC analogs with extended side chains began appearing on online markets in Japan, Europe, and the United States (Tanaka & Kikura-Hanajiri 2024 [Ref 4]; Watanabe et al. 2025 [Ref 6]). Both Δ8-THCH and Δ9-THCH were identified in Japanese internet-distributed oil products from 2022–2023. Δ9-THCH acetate (Δ9-THCH-O) was first reported in commercially available e-cigarette liquids by Watanabe et al. (2025 [Ref 6]). Products are frequently mislabelled regarding their actual cannabinoid content (Watanabe et al. 2025 [Ref 6]).

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## Subjective Effects

**No controlled human studies exist for THCH.** All effect descriptions derive from extrapolation of class pharmacology (CB1 full agonism), animal data, and uncontrolled consumer reports.

**Published review-level characterisation (Caprari et al. 2024 [Ref 7]; Zawatsky et al. 2024 [Ref 9]):**  
THCH is discussed within comprehensive reviews of designer THC compounds as a potent CB1 full agonist expected to produce cannabimimetic effects qualitatively similar to Δ9-THC but quantitatively more intense given its higher CB1 potency. Reviews note that subjective effects data for THCH specifically is sparse and that published literature significantly lags behind the recreational market.

**Anecdotal/consumer reports (non-peer-reviewed; label as such):**  
Consumer sources consistently describe THCH effects as:
- Intensely euphoric and sedating
- Relaxation prominent; body-heaviness reported
- Sensory enhancement noted
- Duration reportedly longer than Δ9-THC (consumer estimates 4–6 hours for tinctures, potentially up to 8 hours for edibles — unverified)
- Onset reportedly comparable to or faster than Δ9-THC
- Some consumer sources claim 5–10× greater subjective potency than Δ9-THC — unverified, likely exaggerated marketing claim

**PsychonautWiki status:** As of the research date, the PsychonautWiki article for THCH is a stub with zero experience reports and explicitly states: "The subjective effects have not been fully understood."

**Animal data relevant to effects:**  
In mouse pharmacological studies, n-hexyl-Δ9-THC (THCH) is implied to produce the full cannabinoid tetrad — hypomotility, antinociception, catalepsy, decreased rectal temperature — by analogy with the established tetrad activity of THCP (Citti et al. 2019 [Ref 14]) and by the general pharmacological characterisation of the homologous series. **FLAG FOR REVIEW:** No published tetrad data specific to THCH was identified. This is class inference.

**Expected effect profile (from CB1 full agonism and class inference):**  
- *Body:* sedation, muscle relaxation, appetite enhancement, pain suppression, dry mouth
- *Cognitive:* cognitive impairment, memory suppression, thought deceleration, humor enhancement
- *Feeling:* euphoria, anxiety (dose-dependent), paranoia (at higher doses)
- *Perception:* visual/auditory distortions at higher doses (consistent with strong CB1 agonism)
- *Time:* time alteration
- *Self:* disinhibition, derealization

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## Safety & Toxicity

### Published Human Adverse Events

**Japan adverse event data (National Consumer Affairs Center of Japan 2023 [Ref 16]):**  
Following the appearance of THCH-containing products on the Japanese market, the National Consumer Affairs Center of Japan reported **at least nine safety incidents** attributed to THCH product consumption prior to its scheduling in August 2023. Documented symptoms included:

- Nausea and hallucinations
- Numbness in the upper body including the face
- Wandering/uncontrolled eye movements
- Severe dizziness
- Loss of consciousness (documented case: unconsciousness for two days)
- Intensive care unit (ICU) admission in at least one case

**No deaths were documented** in the available Japanese adverse event data, though serious harm requiring ICU care was confirmed.

### No LD50 Data

No LD50 or acute toxicity thresholds specific to THCH have been published. **FLAG FOR REVIEW:** Safety-critical value — no LD50 data available; no therapeutic index can be calculated.

### Analytical Toxicology

THCH is detectable in blood and urine using validated LC-MS/MS methods (Muir et al. 2025 [Ref 3]; Schirmer et al. 2025 [Ref 21]). Standard cannabinoid immunoassay (ELISA) screens show reduced cross-reactivity for extended-chain THC homologs like THCH compared to Δ9-THC (Patton et al. 2024 [Ref 15]), meaning standard drug screens may not reliably detect THCH.

### General Cannabinoid Cardiovascular/Respiratory Risk

By class inference, CB1 full agonists share risks common to Δ9-THC: tachycardia (from CB1-mediated sympathetic activation), potential bronchospasm from vaping, and cardiovascular strain in predisposed individuals. THCH's higher CB1 potency implies these risks may manifest at lower doses than Δ9-THC. **FLAG FOR REVIEW:** Substance-specific cardiovascular/respiratory toxicity data does not exist.

### Vaping-Specific Risks

Products containing THCH are frequently sold as vaping liquids (Watanabe et al. 2025 [Ref 6]; Tanaka & Kikura-Hanajiri 2024 [Ref 4]). THCH acetate (THCH-O) shares structural features with other acetylated cannabinoids that generate ketene upon heating — a toxicant associated with EVALI (E-cigarette or Vaping product Use-Associated Lung Injury). **FLAG FOR REVIEW:** THCH-O-specific ketene generation studies were not found; this is inference from the acetate ester class.

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## Harm Reduction

**No published harm reduction protocols specific to THCH exist.** The following is derived from class pharmacology and regulatory guidance.

- **Product labelling unreliable:** Multiple forensic studies confirm that products claiming specific cannabinoid content frequently contain different or additional unlabelled cannabinoids, including THCH (Watanabe et al. 2025 [Ref 6]; Tanaka & Kikura-Hanajiri 2024 [Ref 4]).
- **Dose unpredictability:** THCH's higher CB1 potency than Δ9-THC means THC-calibrated doses will likely underestimate potency. Dose titration appropriate for Δ9-THC is inadequate.
- **Testing:** No specific immunoassay or rapid test kits for THCH validated for consumer harm reduction use were found. LC-MS/MS required for confirmed identification.
- **Contraindications (class inference):** Personal or family history of psychosis, cannabis use disorder, or cardiovascular disease; pregnancy and breastfeeding; concomitant use of CNS depressants, alcohol, or sedating medications.
- **Emergency response:** As for severe cannabinoid intoxication — supportive care; benzodiazepines for agitation/anxiety; monitoring for cardiovascular compromise. Japan case data documents the potential for prolonged unconsciousness requiring ICU-level monitoring.

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## Tolerance & Dependence

**No published tolerance or dependence data specific to THCH exists.**

**Class inference from Δ9-THC and CB1 agonist pharmacology:**
- Repeated CB1 full agonism produces CB1 receptor downregulation and desensitisation via β-arrestin2 recruitment and receptor internalisation — the mechanism investigated by Janssens et al. (2024 [Ref 2]) for this compound class
- Cross-tolerance with Δ9-THC and other CB1 agonists is expected given the shared receptor target
- Dependence liability consistent with CB1 full agonism; higher potency may accelerate tolerance development relative to Δ9-THC
- Withdrawal characterisation: by analogy with cannabis use disorder (cannabis withdrawal syndrome per DSM-5) — irritability, insomnia, appetite disturbance, anxiety, restlessness

**FLAG FOR REVIEW:** All tolerance and dependence data is class inference. No published studies on THCH-specific tolerance or dependence exist.

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## Interactions

**No published drug interaction studies specific to THCH exist.**

**Class inference from Δ9-THC pharmacology:**

- **CNS depressants (alcohol, benzodiazepines, opioids, barbiturates):** Additive CNS depression; increased sedation, respiratory depression risk
- **CYP2C9 inhibitors (e.g., fluconazole, amiodarone):** Expected to increase THCH plasma exposure by reducing hepatic metabolism; analogous to documented THC-drug interactions
- **CYP3A4 inducers (e.g., rifampicin, carbamazepine, St John's Wort):** Expected to reduce THCH plasma levels
- **Serotonergic agents:** No specific serotonin syndrome risk from CB1 agonism alone; indirect interaction possible via 5-HT1A modulation by endocannabinoid system
- **Anticholinergics:** Additive dry mouth, tachycardia
- **Cardiovascular medications:** Additive cardiovascular effects (tachycardia) with stimulants; additive hypotension with antihypertensives

**FLAG FOR REVIEW:** All interaction data is class inference from Δ9-THC pharmacology.

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## Legal Status

### Japan
Δ8-THCH and Δ9-THCH were classified as **"designated substances"** under the Act on Securing Quality, Efficacy and Safety of Products Including Pharmaceuticals and Medical Devices. The designation was announced on **July 25, 2023**, by the Ministry of Health, Labour and Welfare, with effect from **August 4, 2023** (National Consumer Affairs Center of Japan 2023 [Ref 16]; ChemLinked 2023 [Ref 23]). Manufacturing, import, sale, carriage, and non-medical possession are prohibited.

### United Kingdom
The Advisory Council on the Misuse of Drugs (ACMD) self-commissioned a review of semi-synthetic cannabinoids, published in **May 2025** (ACMD 2025 [Ref 22]). The ACMD recommended:
- Named semi-synthetic cannabinoids (including THC homologs of this class) be controlled under **Class B** of the Misuse of Drugs Act 1971 and **Schedule 1** of the Misuse of Drugs Regulations 2001
- Generic text for cannabinoids in the Misuse of Drugs Act be amended to capture psychoactive semi-synthetic cannabinoids not yet explicitly named

The UK Home Secretary accepted the ACMD recommendation. As of the research date (May 2026), consultation on amending the generic cannabinoid text is underway. **FLAG FOR REVIEW:** Confirm whether THCH has been explicitly named in the resulting legislation or covered via the generic text amendment.

### Czech Republic
Expanded ban to include THCH among 11 additional HHC derivatives in **July 2024** (web-retrieved, no primary legal text verified).

### European Union
- **France:** Banned THCH among cannabinoids structurally related to THC (date not precisely established from available sources; consistent with 2023 post-HHC-ban expansion)
- **EU Early Warning System:** Δ8-THCH formally notified in May 2024 to the EU Early Warning System as a new psychoactive substance (web-retrieved via search synthesis)
- Other EU member states: variable; monitoring ongoing via EUDA (EUDA 2024 [Ref 24])

### United States
THCH is **not specifically scheduled** under the Controlled Substances Act as of the research date. Its status under the Federal Analogue Act (FAA) is ambiguous — the FAA may apply if THCH is consumed by humans and is structurally and pharmacologically analogous to a Schedule I controlled substance (i.e., Δ9-THC). Hemp-derived THCH occupies a legal grey zone under the 2018 Farm Bill framework if total Δ9-THC content remains below 0.3%, though the DEA has signalled that THC isomers produced from hemp are still controlled (Zawatsky et al. 2024 [Ref 9]). **FLAG FOR REVIEW:** Specific DEA guidance on THCH by name was not found; US legal status requires legal expert verification.

### Canada and Australia
No specific scheduling data for THCH found in peer-reviewed or government sources. Under Canada's CDSA and Australia's scheduling frameworks, THCH would likely be captured by generic THC/cannabinoid provisions, but no confirmed jurisdictional statements were found. **FLAG FOR REVIEW.**

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## Clinical Trials

**No clinical trials for THCH found.** Search of ClinicalTrials.gov returned zero results for "tetrahydrocannabihexol" or "THCH." Consistent with the substance's emerging/novel status and lack of any therapeutic development program.

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## Community Feedback Analysis

No community feedback submitted in Part A2 of the brief.

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## Gaps & Flags

### Safety-Critical Gaps (FLAG FOR REVIEW)
1. **No published CB1 Ki or EC50 values for THCH.** Janssens et al. (2024) confirmed higher CB1 potency than Δ9-THC via β-arrestin2 assay, but specific numeric values not retrievable from abstract alone. Generation agent should NOT assign specific binding values without primary source access.
2. **No LD50 or acute toxicity data.** Dose ranges cannot be anchored to safety thresholds. Any proposed dose ranges for the article must be flagged as unverified extrapolation.
3. **No human pharmacokinetic studies.** Bioavailability, Tmax, half-life, volume of distribution: all unknown for THCH.

### Structural/Pharmacological Inference Flags
4. **CB2 receptor data:** Class inference only; no THCH-specific data found.
5. **CYP enzyme involvement:** Inferred from Δ9-THC metabolism data; THCH-specific CYP studies absent.
6. **Tetrad pharmacological test data:** THCH was not explicitly tested in the cannabinoid tetrad. Effects inferred from class and THCP analog data.
7. **Tolerance and dependence data:** All class inference from Δ9-THC pharmacology.
8. **Drug interactions:** All class inference. No THCH-specific interaction studies exist.
9. **CB2 vs CB1 selectivity ratio:** Unknown for THCH; structurally extrapolated.

### Legal Status Flags
10. **US scheduling status:** No explicit DEA scheduling action for THCH found. Federal Analogue Act applicability uncertain. Requires legal expert confirmation.
11. **UK implementation date:** ACMD Class B recommendation (May 2025) accepted by government; legislation not yet confirmed in force as of research date.
12. **Canada/Australia:** No confirmed scheduling data found; cannot state these are scheduled or unscheduled.

### Dose & Duration Data Notes
- **Consumer reports estimate 4–6h tincture / up to 8h edible duration** — unverified, sourced from non-peer-reviewed consumer industry sources. No controlled study confirms this.
- **Potency claims of "5–10× stronger than THC"** circulating in consumer sources are unverified marketing claims without pharmacological validation.
- **No dose data whatsoever** in the published literature. The generation agent must flag any proposed dose range as based entirely on class inference from Δ9-THC, with adjustment for approximate higher CB1 potency. **Proposed editorial approach:** if dose data is included in the article, label as "theoretical estimate based on CB1 receptor pharmacology — no human dose data published" and recommend extremely conservative starting doses given higher-than-THC CB1 potency.

### Source Limitations
13. The Janssens et al. (2024 [Ref 2]) paper is the most pharmacologically significant THCH-specific source, but the full text was inaccessible; specific THCH EC50/Emax values remain unconfirmed from the abstract.
14. The Caprari et al. (2024 [Ref 7]) "designer THC" comprehensive review covers THCH but full text was inaccessible; cited data from abstract only.
15. All Roger Adams 1941–1949 parahexyl papers are pre-digital and unverifiable via API; historical narrative sourced from web-retrieved secondary sources.
16. ACMD UK full report (PDF) was unreadable in the fetched format; THCH-specific content within the 63-page report not confirmed.