CBN
Viewing r1 — May 7, 2026 — CURRENT
Back to HistoryInteractions, related substances, and reports reflect the current entry and are not shown for historical revisions.
CBN (cannabinol) is a naturally-occurring cannabinoid of the dibenzopyran class. It is a degradation product of THC, formed as cannabis ages. CBN is a partial agonist at CB1 and CB2 receptors,[1] producing its effects by weakly engaging the endocannabinoid system at one-quarter to one-tenth the potency of THC.[2]
Psychedex is in open beta. We are still fine-tuning the generation and review process. Please double-check sources.
CBN was the first phytocannabinoid ever isolated, extracted from cannabis resin in 1896 — nearly seven decades before THC was identified.[3] Its structural elucidation in the 1940s launched synthetic cannabinoid chemistry and enabled Mechoulam's identification of THC in 1964.[4] Today CBN is widely marketed in sleep-oriented consumer products, though a systematic review found the evidence insufficient to support these claims.[5]
Subjective effects include mild sedation, relaxation, and appetite stimulation. At doses found in commercial products, CBN produces no perceptible intoxication — its reputation as a sleep aid likely reflects co-occurrence with THC and sedating terpenes in aged cannabis rather than an intrinsic property. No characteristic unsought effects have been identified at typical oral doses; at high intravenous doses, mild heart rate increase occurs.
CBN shows no evidence of abuse liability,[6] and preclinical data suggest an acceptable safety profile at therapeutic doses.[7] The primary risk is uncharacterized drug interactions — CBN activates the pregnane X receptor, potentially reducing blood levels of medications metabolized by CYP3A4.[8] No controlled pharmacokinetic study of isolated CBN in humans has been published; the current understanding rests on preclinical data and analogy to other cannabinoids.
History[edit]
Discovery
CBN was the first phytocannabinoid ever isolated, predating the identification of THC by nearly seven decades. In 1896, Wood, Spivey, and Easterfield fractionated Charas — the resinous exudate of unfertilized female Cannabis indica buds — by vacuum distillation and isolated a compound they named cannabinol.[9] The molecular formula was initially misassigned as C₁₈H₂₄O₂ and corrected to C₂₁H₂₆O₂ three years later.[3]
Structure and scientific impact
The complete structure of CBN was independently elucidated in the early 1940s by Roger Adams in the United States and Alexander Todd in the United Kingdom.[3][4] This work laid the groundwork for synthetic cannabinoid chemistry and enabled Raphael Mechoulam and Yechiel Gaoni to identify Δ⁹-THC in 1964. The 1970s brought direct human pharmacology studies: intravenous CBN at ~12–14 mg produced mild intoxication, while oral doses up to 100 mg produced none — revealing the compound's poor oral bioavailability.[10]
Modern era
A 2021 systematic review of all eligible human studies concluded the evidence is insufficient to support either cannabis-like effects or sleep-promoting claims for CBN.[5] Despite this, CBN has become one of the most commercially marketed minor cannabinoids, appearing in hundreds of sleep products at doses typically ≤5 mg — far below doses tested in any published study. The first formal randomized controlled trial investigating CBN for insomnia — the CUPID study, testing 30 mg and 300 mg versus placebo — has been protocolized but results remain unpublished.[11]
The name "cannabinol" was coined by Wood, Spivey, and Easterfield in 1896 — a straightforward derivation from "cannabis." A notable tragedy attended the early research: Spivey died in a laboratory accident during a large-scale Étard oxidation conducted while attempting to elucidate a related compound.[9]
Chemistry[edit]
Structural class
CBN belongs to the dibenzopyran class of cannabinoids within the broader terpenophenolic family of Cannabis sativa phytochemistry.[12] It shares the tricyclic scaffold of classical cannabinoids — THC, Δ⁸-THC, and CBD — but is distinguished by full aromatization of its central ring. Where THC contains a partially saturated cyclohexene ring, CBN's corresponding ring is fully aromatic, a structural consequence of oxidative aromatization.
Molecular properties
| Molecular formula | C₂₁H₂₆O₂ |
| Molecular weight | 310.4 g/mol |
The molecular structure comprises a benzo[c]chromene ring system with a phenolic hydroxyl group, gem-dimethyl substitution, and an n-pentyl side chain responsible for cannabinoid receptor activity.[13] The fully aromatic A-ring distinguishes CBN from all other major phytocannabinoids and accounts for its distinct chromatographic behavior.
Stereochemistry
CBN possesses no chiral centers. The oxidative aromatization that converts THC to CBN eliminates the sp³ carbon that confers chirality on THC. CBN does not exist as stereoisomers, and questions of enantioselective pharmacology do not apply.
Stability and formation
CBN is lipophilic, poorly soluble in water, and freely soluble in organic solvents including ethanol and chloroform.[12] It forms through the oxidative aromatization of THC during storage, heat, or light exposure.[14] Fresh cannabis contains very little CBN; older or poorly stored material contains substantially more. CBN levels in cannabis extracts serve as a quality marker for aging — elevated CBN:THC ratios indicate prolonged or improper storage.
The n-pentyl side chain at position 3 drives cannabinoid receptor binding; shorter or longer chains significantly reduce potency at both CB1 and CB2.
Pharmacology[edit]
Mechanism of action
CBN is a partial agonist at both CB1 and CB2 cannabinoid receptors, with substantially lower potency than THC. Functional assays place CBN at roughly one-quarter to one-tenth the potency of THC at CB1.[2] At CB2, CBN binds with affinity approaching that of THC — within roughly threefold.[1] A mouse drug discrimination study confirmed partial cannabimimetic activity: CBN partially substituted for THC, consistent with weak CB1 engagement.
CBN's pharmacology extends beyond cannabinoid receptors. It activates the TRPA1 ion channel, contributing to analgesic and anti-inflammatory potential.[15] It acts as a potent agonist of the human pregnane X receptor (PXR), which induces CYP3A4 enzyme expression — a mechanism carrying significant drug interaction implications.[8] CBN also demonstrates allosteric modulation of GABA_A receptors, linked to anti-seizure effects in preclinical models.[16][17]
At CB2, CBN exhibits context-dependent pharmacology: while standard binding assays show partial agonism, it acts as a CB2 antagonist in the context of microglial cell migration triggered by pathological neuronal stimulation.[18] This biased pharmacology has implications for neuroinflammatory processes.
CBN modulates immune function through pathways independent of CB1 and CB2. It enhances IL-2 expression in T cells through a calcium-dependent mechanism not blocked by CB2 antagonists,[19] while separately suppressing inflammatory signaling via inhibition of ERK MAP kinase.[20]
Pharmacokinetics
No published human pharmacokinetic study has specifically characterized isolated CBN. In one analytical study, CBN was undetectable in plasma after oral administration of cannabis extract containing trace amounts, suggesting extremely poor oral bioavailability.[21]
General cannabinoid pharmacokinetic principles apply: high lipophilicity drives extensive tissue distribution, extensive first-pass liver metabolism limits oral bioavailability, and elimination is prolonged by redistribution from fat tissue.[22] CBN-specific parameters — peak concentration time, oral bioavailability, and half-life — remain uncharacterized for isolated CBN dosing.
CBN is metabolized rapidly by multiple liver enzymes and is the most rapidly biotransformed among phytocannabinoids tested.[23] This rapid breakdown likely contributes to its poor oral bioavailability through extensive first-pass metabolism.
Neuroscience[edit]
Where it acts
CBN engages the endocannabinoid system through CB1 receptors concentrated in the cerebral cortex, hippocampus, basal ganglia, and cerebellum — regions governing cognition, memory, motor control, and reward. As a partial CB1 agonist at one-quarter to one-tenth the potency of THC,[2] CBN produces attenuated versions of THC's neural effects: modest modulation of hippocampal memory encoding, mild anxiolysis via amygdala CB1 receptors, and appetite stimulation through hypothalamic feeding circuits.[24]
Separately, CBN blocks microglial migration driven by the endocannabinoid 2-AG,[18] a mechanism relevant to neuroinflammation. This CB2 antagonism may contribute to the delayed disease onset observed in an ALS mouse model,[25] though the precise contribution was not isolated.
Why it matters
CBN's partial agonism interacts with endocannabinoid tone — the baseline level of endocannabinoid signaling that maintains homeostasis across neural circuits. In states of high endocannabinoid tone, a partial agonist can function as a functional antagonist by displacing more efficacious endogenous ligands; when tone is low, CBN acts as a net agonist. This context-dependence predicts that CBN's neural effects vary with stress, inflammation, and metabolic state.
The anti-seizure activity observed in preclinical hemp extract studies[16] implicates GABA_A receptor modulation — a mechanism distinct from CB1 agonism that enhances inhibitory neurotransmission and raises seizure threshold.
No human neuroimaging studies of CBN have been published. The receptor occupancy curve for CBN at CB1 in human brain is unknown — no PET studies have been conducted. Whether CBN's GABA_A modulation produces distinct sleep-architecture changes (increased spindle density, altered slow-wave activity) remains untested; the CUPID trial includes sleep staging as a secondary endpoint.[11]
Subjective Effects[edit]
CBN's experiential character is defined by the near-absence of perceptible psychoactivity. At commercial product doses, most users report no intoxication. Even at 100 mg oral, controlled studies detected no cannabis-like effects — the compound's sedative reputation likely reflects its co-occurrence with THC and sedating terpenes in aged cannabis rather than an intrinsic property. Route matters profoundly: intravenous delivery at pharmacological doses produces mild THC-like effects that oral dosing at higher absolute amounts does not replicate, underscoring bioavailability as the gatekeeper of subjective awareness.
Relative to Δ⁹-THC, CBN occupies a position of markedly attenuated psychoactivity — roughly one-quarter to one-tenth the potency, further diminished by poor oral bioavailability. Compared to CBD, CBN retains substantially greater cannabinoid receptor affinity and a greater theoretical capacity for cannabimimetic effects, though neither compound produces the robust intoxication characteristic of THC at typical doses.
Effect Grid
No common dose range has been pharmacologically validated for CBN. Commercial products use ≤5–10 mg oral, but this dosing is market-driven rather than evidence-based. The CUPID insomnia trial tests 30 mg and 300 mg CBN versus placebo — doses far exceeding commercial products — but results remain unpublished as of May 2026.
Based on CBN's CB1 partial agonism (1/4 to 1/10 of THC potency), a common-range experience — if achievable orally — would likely involve mild sedation, modest appetite enhancement, gentle pain suppression via TRPA1 agonism, and subtle muscle relaxation. Cognitive effects would be minimal. No intoxication, perceptual distortion, or euphoria would be expected at this level.
Modeled from the effect's dose-dependence curve — not per-substance measurements.
Dry mouth · Body high · Bodily heaviness · Appetite enhancement · Dizziness
Dizziness
Safety[edit]
- Acute toxicity
- Negligible
- Chronic toxicity
- Low
- Withdrawal
- None
- Tolerance buildup
- slow
- Tolerance reset
- —
- Physical
- None
- Psychological
- Negligible
- Compulsive redosing
- Negligible
- Dose escalation
- Negligible
- Cross-tol.
- Δ⁹-THC
Toxicity
No lethal dose has been established for CBN in humans or animals. No therapeutic index has been calculated, as human dose-response relationships remain uncharacterized.
Preclinical data
A subacute mouse study using water-soluble CBN nano-emulsion at therapeutic doses found an acceptable safety profile with no organ toxicity.[7] Cytotoxicity has been observed in neuroblastoma cells at high concentrations in vitro, but the concentrations required substantially exceed achievable plasma levels.[26]
Clinical data
The largest published clinical safety dataset comes from the INM-755 Phase 2 trial in 19 epidermolysis bullosa patients (topical route). No serious drug-related adverse events were recorded, no participants withdrew, and the only possibly related systemic event was moderate headache in one participant.[27] Historical 1970s human studies with intravenous and oral CBN did not report severe adverse events.[5]
No reproductive or developmental toxicity data for CBN have been published. safety citation needed
Psychological risks
CBN produces minimal psychoactivity at doses used in commercial products (≤5–10 mg oral). At high intravenous doses (~12–14 mg IV), mild cannabis-like intoxication was reported, including a self-reported "high" and 25% heart rate increase.[10] At oral doses up to 100 mg, no psychoactive effects were observed.
Non-psychoactive cannabinoids as a class do not produce intoxicating, cognitive, or rewarding properties in humans.[6] No published reports of CBN-induced anxiety, paranoia, or psychological distress were identified. The CUPID trial includes cognitive performance and simulated driving as safety endpoints, providing the first controlled data at pharmacological doses.[11]
Tolerance and dependence
No published data characterize CBN-specific tolerance development in humans or animals. Based on its CB1 partial agonism, tolerance would follow downregulation mechanisms similar to THC, but likely slower and less pronounced given CBN's lower potency. Cross-tolerance with THC is expected mechanistically but has not been directly studied.
No self-administration, conditioned place preference, or withdrawal studies have been published for CBN. Non-psychoactive cannabinoids show no intoxicating or rewarding properties,[6] consistent with very low abuse liability. The absence of evidence for dependence is not evidence of safety.
Drug interactions
All drug interaction data for CBN derive from in vitro assays or theoretical extrapolation. No human pharmacokinetic interaction studies have been published. safety citation needed
CYP-mediated interactions
PXR/CYP3A4 induction: CBN activates the pregnane X receptor at concentrations as low as 0.3 µM, inducing CYP3A4 expression.[8] Chronic use could reduce blood levels of immunosuppressants (tacrolimus, cyclosporine), statins (atorvastatin, simvastatin), antiretrovirals, and other narrow-therapeutic-index drugs metabolized by CYP3A4. This has not been confirmed in vivo.
CYP2C9 competition: As a CYP2C9 substrate,[28][23] CBN may competitively inhibit the metabolism of warfarin, phenytoin, and some NSAIDs, potentially increasing their blood levels.
Transporter-mediated interactions
CBN inhibits the ABCG2 (BCRP) efflux transporter,[29] potentially increasing bioavailability of certain chemotherapy drugs. Prolonged CBN exposure reduces P-glycoprotein expression, sensitizing drug-resistant cells to vincristine.[30] Both findings lack in vivo confirmation.
Additive effects
Synergistic sedation with THC is expected based on additive CB1 agonism and is the likely basis for the sedative reputation of aged cannabis. Additive central nervous system depression with alcohol, benzodiazepines, or opioids is theoretically possible but uncharacterized for CBN.
| Interacting drug/class | Mechanism | Expected direction | Evidence level |
|---|---|---|---|
| CYP3A4 substrates (immunosuppressants, statins, antiretrovirals) | PXR-mediated CYP3A4 induction | Reduced substrate levels | In vitro |
| CYP2C9 substrates (warfarin, NSAIDs) | Competitive substrate inhibition | Increased substrate levels possible | In vitro |
| ABCG2/BCRP substrates (chemotherapy agents) | Transporter inhibition | Increased substrate levels | In vitro |
| Δ⁹-THC | Additive CB1 partial agonism | Enhanced cannabimimetic effects | Preclinical/anecdotal |
| CNS depressants (alcohol, benzodiazepines, opioids) | Additive CNS depression via CB1 | Enhanced sedation | Theoretical |
Contraindications
Concurrent CYP3A4 substrate medications
CBN's induction of CYP3A4[8] is a relative contraindication for individuals taking narrow-therapeutic-index drugs metabolized by this enzyme. Immunosuppressants, certain antiretrovirals, and statins are of particular concern. Clinical data quantifying this interaction are absent.
Concurrent CYP2C9 substrate medications
Competitive inhibition at CYP2C9 poses a relative contraindication for concurrent warfarin use, where even modest metabolic changes can produce clinically significant alterations in clotting time.[28]
Pregnancy and lactation
No CBN-specific reproductive or developmental toxicity data have been published. Consistent with general cannabinoid precautions, CBN should be considered contraindicated in pregnancy and lactation until safety data are available. safety citation needed
Driving and machinery operation
While CBN is minimally psychoactive at typical commercial doses, a theoretical concern exists at higher pharmacological doses. The CUPID trial includes simulated driving as a safety endpoint.[11]
THC urine test cross-reactivity
Standard immunoassay-based THC urine tests may cross-react with CBN metabolites. Individuals subject to workplace or legal drug testing should be aware that CBN consumption could produce a positive screening result. Confirmatory testing can differentiate CBN from THC metabolites.[21]
Harm Reduction[edit]
Forms & Identification
Most CBN products are sold as isolate-based formulations — tinctures, capsules, and gummies — rather than raw plant material. Because CBN is a minor cannabinoid typically present at low concentrations in cannabis, commercial products rely on either synthetic CBN or concentrated extracts. Third-party certificates of analysis (COAs) are the primary verification tool: check for CBN content, residual THC levels, heavy metals, pesticides, and microbial contaminants. Products without accessible COAs should be treated with skepticism.
The most relevant testing concern for CBN products is accurate cannabinoid content and THC contamination — not adulterant substitution. Because CBN is derived from or co-occurs with THC, products may contain more residual THC than labeled, which matters for drug testing and for individuals sensitive to THC effects.
Guidelines
- Start with the lowest available dose (typically 2.5–5 mg oral) and assess effects before increasing
- Allow at least 90 minutes for onset when taken orally — poor bioavailability means effects may be delayed or absent
- Purchase only from manufacturers who provide third-party COAs verifying cannabinoid content and contaminant testing
- If combining with THC-containing products, account for additive effects and start with lower doses of both
- Do not assume CBN will not trigger a positive drug test — immunoassay cross-reactivity with THC metabolites has been documented[21]
- Avoid CBN if taking immunosuppressants, blood thinners (warfarin), or other narrow-therapeutic-index medications without consulting a physician
Set & Setting
CBN's minimal psychoactivity at commercial doses means set and setting are less critical than for psychoactive cannabinoids. If using CBN at higher experimental doses or in combination with THC, a calm and familiar environment reduces the likelihood of unwanted anxiety. Evening use in a sleep-conducive setting aligns with the most common use pattern.
Aftercare & integration. CBN's minimal psychoactivity means formal integration practices are generally unnecessary. If unexpected intoxication occurred due to mislabeled products or THC contamination, standard cannabis aftercare applies: hydrate, eat light meals, and allow time for full clearance. Residual grogginess the morning after higher doses is possible — avoid driving or operating heavy machinery until fully alert.
If CBN was taken for sleep and proved ineffective, this is consistent with the current evidence base. Consider discussing sleep concerns with a healthcare provider rather than escalating the dose.
Recovery & Support
CBN does not produce physical dependence or a recognized withdrawal. If habitual CBN use has developed as part of a broader pattern of cannabis product reliance, the underlying sleep or anxiety concerns driving use may benefit from professional evaluation. Cognitive behavioral therapy for insomnia (CBT-I) is the first-line evidence-based treatment for chronic sleep difficulties and is effective without pharmacological intervention.
Recovery resources, crisis lines, and support pathways → View all
Emergency Response
CBN emergencies are extremely unlikely at typical doses. The primary risks involve drug interactions or unexpected THC content in poorly labeled products rather than CBN toxicity itself.
Recognizing an emergency: Significant intoxication after taking a CBN-only product suggests the product contained more THC than labeled. Symptoms of concern include severe confusion, extreme anxiety or panic, tachycardia, or loss of consciousness.
Immediate steps:
- 1. Move the person to a safe, quiet environment
- 2. Reassure them that cannabis-related effects are temporary and not life-threatening
- 3. If the person is unresponsive or breathing abnormally, call emergency services immediately
- 4. Place an unconscious person in the recovery position
- 5. Do not leave an intoxicated person alone
What to tell the dispatcher: Name the substance (CBN product, possible THC contamination), the amount taken, the time of ingestion, and current symptoms. Good Samaritan laws in many jurisdictions protect callers from legal consequences.
Legal Status[edit]
CBN occupies a complex and variable legal position internationally. Unlike Δ⁹-THC, CBN is not universally classified as a controlled substance, but its status depends on source material (hemp vs. marijuana), jurisdictional cannabinoid scheduling frameworks, and evolving legislation. It is not explicitly listed as a Schedule I substance under the United States Controlled Substances Act, but is classified as a controlled drug in the United Kingdom and a prohibited substance in Australia.[31]
| Jurisdiction | Classification | Key provisions |
|---|---|---|
| United States (federal) | Not explicitly Schedule I; hemp-derived CBN legal under 2018 Farm Bill (≤0.3% Δ⁹-THC) | Federal legislation effective November 12, 2026 shifts from Δ⁹-THC threshold to total THC threshold (including THCA); products previously legal may be reclassified. Marijuana-derived CBN inherits Schedule I classification of source material.[31] |
| United Kingdom | Class B controlled drug (Misuse of Drugs Act 1971, Schedule 2) | Cannabis-based medical products containing CBN legal only when prescribed by specialist. Products must not exceed 1 mg CBN threshold for exemption.[31] |
| Australia | Schedule 9 prohibited substance (Poisons Standard) | Manufacture, possession, sale, or use without specific license or authority is illegal.[31] |
| Canada | Regulated under the Cannabis Act | Cannabis-derived CBN regulated as a cannabis product. Hemp-derived CBN regulation may differ. citation needed |
| European Union | Variable by member state | Often restricted due to perceived psychoactive potential. Some countries (e.g., Poland) permit CBN as non-psychoactive; Germany, Austria, and others follow country-specific cannabinoid schedules. citation needed |
The shifting United States regulatory landscape merits particular attention. The 2018 Farm Bill legalized hemp and hemp-derived compounds containing ≤0.3% Δ⁹-THC, effectively making hemp-derived CBN federally legal. The transition to a total THC threshold (including THCA) effective November 12, 2026 may affect the legal status of some products.
A DEA final order in April 2026 rescheduled FDA-approved marijuana products from Schedule I to Schedule III, but this affects only FDA-approved formulations and does not apply to CBN-containing supplements or consumer products.
references
- [1] ^abShowalter VM, Compton DR, Martin BR, Abood ME (1996) Evaluation of binding in a transfected cell line expressing a peripheral cannabinoid receptor (CB2): identification of cannabinoid receptor subtype selective ligands. — The Journal of pharmacology and experimental therapeutics PMID:8819477
- [2] ^abcWiley JL, Marusich JA, Blough BE, et al. (2024) Evaluation of cannabimimetic effects of selected minor cannabinoids and Terpenoids in mice. — Progress in neuro-psychopharmacology & biological psychiatry doi:10.1016/j.pnpbp.2024.110984
- [3] ^abcAppendino G (2020) The early history of cannabinoid research — Rendiconti Lincei. Scienze Fisiche e Naturali doi:10.1007/s12210-020-00956-0
- [4]
- [5] ^abcCorroon J (2021) Cannabinol and Sleep: Separating Fact from Fiction. — Cannabis and cannabinoid research doi:10.1089/can.2021.0006
- [6] ^abcHeal DJ, Gosden J, Smith SL (2024) A critical assessment of the abuse, dependence and associated safety risks of naturally occurring and synthetic cannabinoids — Frontiers in Psychiatry doi:10.3389/fpsyt.2024.1322434