MN-18
An indazole carboxamide with a naphthalene head, an analogue of NNEI, high affinity at CB1 and CB2, classified as a narcotic in France.
Harm-reduction warning
No characterised human dose: animal / in vitro data only. Effect profile, safety margin and acute toxicity are not documented in human clinical practice. Extremely potent compound: severe effects, seizures and deaths reported in the literature.
C₂₃H₂₃N₃O
CAS 1391484-80-2
- Family
- Synthetic CB receptor agonistNew psychoactive substance
- Molar mass
- 357.40 g/mol
Updated on
In plain terms
MN-18 is a synthetic cannabinoid made in a laboratory, spotted in Japan in 2014. It does not exist in hemp and has nothing to do with cannabidiol. It binds very strongly to the cannabinoid receptors in laboratory assays, and it is classified as a narcotic in France.
Receptors and activity
Target network
- Activates
The lower the cited value, the closer the target sits to MN-18: one ring per factor of 100. A target with no measured value stays on the edge.
Where these targets live
Where each target has been found in humans, according to the cited studies. The map shows the target, not an effect of MN-18.
CB1CB1 found in 7 regions of the body
- Basal gangliadenseMost dense in basal ganglia outflow nuclei1
- CerebellumdenseVery dense in the cerebellum1
- HippocampusdenseVery high concentrations in the hippocampus2
- AmygdaladenseHigh concentrations in the amygdala2
- CortexpresentPresent throughout the neocortex2
- Adipose tissuepresentExpressed in adipose tissue3
- GutpresentColonic epithelium, smooth muscle and plexus4
Map sources
- Herkenham M et al. Cannabinoid receptor localization in brain. Proc Natl Acad Sci U S A, 1990 (new tab)
- Glass M et al. Cannabinoid receptors in the human brain: a detailed anatomical and quantitative autoradiographic study in the fetal, neonatal and adult human brain. Neuroscience, 1997 (new tab)
- Engeli S et al. Activation of the peripheral endocannabinoid system in human obesity. Diabetes, 2005 (new tab)
- Wright K et al. Differential expression of cannabinoid receptors in the human colon: cannabinoids promote epithelial wound healing. Gastroenterology, 2005 (new tab)
Cited values
- CB1Partial agonistKi = 3.9 nM · human74 out of 100
Hess et al. 2016, Forensic Toxicol (new tab) · competitive [3H]CP55,940 binding, CHO cell membranes
- CB2Partial agonistKi = 3.5 nM · human74 out of 100
Hess et al. 2016, Forensic Toxicol (new tab) · competitive [3H]CP55,940 binding, CHO cell membranes
Pharmacology
MN-18 is a naphthyl-headed indazole carboxamide, identified in Japan in 2014 with its fluorinated analogue, and the indazole analogue of NNEI (MN-24), which carries an indole in the same place. Hess et al. (2016) measure on human receptors Ki values of 3.86 nM at CB1 and 3.47 nM at CB2, with an efficacy lower than that of Δ9-THC in a cAMP assay. Kevin et al. (2018) compare MN-18 with NNEI: in the rat, after an intraperitoneal injection of 3 mg/kg, plasma half-life is 5.40 h for MN-18 against 11.55 h for NNEI; MN-18 is eliminated faster although it undergoes fewer biotransformations in hepatocytes (10 metabolites against 20). Diao et al. (2017) described its metabolism in human hepatocytes: 13 metabolites, the three most abundant being 1-pentylindazole-3-carboxylic acid, pentyl-carbonylated MN-18 and naphthalene-hydroxylated MN-18. No controlled study in human beings was found.
Key sources.
- Hess C, Schoeder CT, Pillaiyar T, Madea B, Müller CE. Pharmacological evaluation of synthetic cannabinoids identified as constituents of spice. Forensic Toxicol. 2016;34:329-343 (new tab)PMID 27429655
- Diao X, Carlier J, Zhu M, Huestis MA. Human Hepatocyte Metabolism of Novel Synthetic Cannabinoids MN-18 and Its 5-Fluoro Analog 5F-MN-18. Clin Chem. 2017;63(11):1753-1763 (new tab)PMID 28821542
- Kevin RC, Lefever TW, Snyder RW, Patel PR, Gamage TF, Fennell TR, Wiley JL, McGregor IS. Kinetic and metabolic profiles of synthetic cannabinoids NNEI and MN-18. Drug Test Anal. 2018;10(1):137-147 (new tab)PMID 28834241
- Council Framework Decision 2004/757/JHA, consolidated version of 12.01.2026 (annex: substances subject to Union control) (new tab)
History
- Source
- A wholly synthetic molecule, absent from hemp and from every living organism. It was identified in 2014, with its fluorinated analogue, in an ongoing survey of new psychoactive substances in Japan (Diao et al. 2017); MN-18 and NNEI were detected in 2014 and 2015 in recreationally used products in several countries (Kevin et al. 2018). None of this has anything to do with hemp or with cannabidiol products.
Origin
Laboratory synthesis
No known biosynthetic pathway: the molecule is produced by no plant and no living organism. It is entirely synthetic in origin and belongs to the chemical family of the naphthyl-headed indazole-3-carboxamides.
Legal framework
- European Union
It does not appear in the annex to Framework Decision 2004/757/JHA (consolidated version of 12 January 2026), which names only five synthetic cannabinoid agonists: MDMB-CHMICA, ADB-CHMINACA, CUMYL-4CN-BINACA, MDMB-4en-PINACA and 4F-MDMB-BICA. Nor does it appear in annex III of the consolidated ANSM list (tables I and II of the 1971 Convention on Psychotropic Substances).
- France
A narcotic in France, listed by name: the consolidated ANSM list (updated 16 February 2026) cites in annex IV « MN-18 ou N-(naphthalen-1-yl)-1-pentyl-1H-indazole-3-carboxamide », within the family of indazole-3-carboxamide derivatives. That family covers molecules bearing on the nitrogen in position 1 of the indazole a substituent of the alkyl, haloalkyl, halobenzyl or related type, and on the nitrogen of the carboxamide bridge a substituent of the cumyl, naphthyl, adamantyl, benzyl or bicycloheptyl type. Diao et al. (2017) state that MN-18 and 5F-MN-18 were placed on the controlled-substance lists of Japan and a few other countries in 2014.
Sources: EUR-Lex, UNODC, CND, ANSM, IUPHAR/BPS, ChEBI, EUDA. Our method.
Classification
Family, origin and source verification
- Family
Synthetic CB receptor agonist › New psychoactive substance
- Class
indazole-3-carboxamide
- Verification
Classification, sources and binding values checked on 20 October 2026; text read against its sources and Wikipedia.
- Wikipedia (English)
Article paired by the molecule's structure (InChIKey), revision read on 19 October 2026. Read as a second opinion, never cited as a source.
References
- Hess C, Schoeder CT, Pillaiyar T, Madea B, Müller CE. Pharmacological evaluation of synthetic cannabinoids identified as constituents of spice. Forensic Toxicol. 2016;34:329-343 (new tab)PMID 27429655
- Diao X, Carlier J, Zhu M, Huestis MA. Human Hepatocyte Metabolism of Novel Synthetic Cannabinoids MN-18 and Its 5-Fluoro Analog 5F-MN-18. Clin Chem. 2017;63(11):1753-1763 (new tab)PMID 28821542
- Kevin RC, Lefever TW, Snyder RW, Patel PR, Gamage TF, Fennell TR, Wiley JL, McGregor IS. Kinetic and metabolic profiles of synthetic cannabinoids NNEI and MN-18. Drug Test Anal. 2018;10(1):137-147 (new tab)PMID 28834241
- Council Framework Decision 2004/757/JHA, consolidated version of 12.01.2026 (annex: substances subject to Union control) (new tab)
Identifiers
Names
- IUPAC name
- N-naphthalen-1-yl-1-pentylindazole-3-carboxamide
- Other names
- NNEI indazole analogue
Identifiers
- Formula
- C₂₃H₂₃N₃O
- CAS
- 1391484-80-2
- PubChem CID
- 119058030(new tab)
- InChIKey
- UJKHLVOEXULDRU-UHFFFAOYSA-N
- SMILES
- CCCCCN1C2=
CC= CC= C2C(= N1) C(= O) NC3= CC= CC4= CC= CC= C43
LLM ingestion format: a structured superset of the entry (identifiers, binding, versioned legal status). Full corpus.