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Synthetic

MDMB-4en-PINACA

A highly potent full CB1 agonist, classified as a narcotic, associated with deaths and severe poisonings.

Narcotic: named in schedule
Level of detail

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.

C₂₀H₂₇N₃O₃

CAS 2504100-70-1

Family
Synthetic CB receptor agonistNew psychoactive substance
Molar mass
357.40 g/mol

Updated on

In plain terms

MDMB-4en-PINACA is a synthetic cannabinoid made in a laboratory, with no link to hemp: it exists neither in cannabis nor in cannabidiol products. Sold as a powder, as a vaping liquid, on smoking herbs or on impregnated papers, it acts on the same receptors as THC but activates them far more intensely, and the amount actually present in a product remains unpredictable. Twelve deaths and eleven acute poisonings, with other substances present in every case, were associated with it in Europe between 2019 and 2020, and it is scheduled as a narcotic in France as well as internationally.

Receptors and activity

Target network

CB1AgonistKi = 3.3 nM · humanbinding to the hCB1 receptor expressed in HEK cells
  • Activates

The lower the cited value, the closer the target sits to MDMB-4en-PINACA: 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 MDMB-4en-PINACA.

Brain, side view
Body, front view
Blood

CB1CB1 found in 7 regions of the body

  1. Basal gangliadenseMost dense in basal ganglia outflow nuclei1
  2. CerebellumdenseVery dense in the cerebellum1
  3. HippocampusdenseVery high concentrations in the hippocampus2
  4. AmygdaladenseHigh concentrations in the amygdala2
  5. CortexpresentPresent throughout the neocortex2
  6. Adipose tissuepresentExpressed in adipose tissue3
  7. GutpresentColonic epithelium, smooth muscle and plexus4

Map sources

  1. Herkenham M et al. Cannabinoid receptor localization in brain. Proc Natl Acad Sci U S A, 1990 (new tab)
  2. 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)
  3. Engeli S et al. Activation of the peripheral endocannabinoid system in human obesity. Diabetes, 2005 (new tab)
  4. Wright K et al. Differential expression of cannabinoid receptors in the human colon: cannabinoids promote epithelial wound healing. Gastroenterology, 2005 (new tab)

Cited values

  1. CB1AgonistKi = 3.3 nM · human75 out of 100

    WHO, 43rd ECDD (2020) (new tab) · binding to the hCB1 receptor expressed in HEK cells

Bar length follows the measured value (Ki, Kd, EC50 or IC50), on one scale shared by every entry, from 100 µM to 0.1 nM. A target with no cited value has no bar.

Pharmacology

MDMB-4en-PINACA belongs to the indazole-3-carboxamide class: an indazole nucleus, a pent-4-en-1-yl tail, a carboxamide link and a tert-leucine methyl ester head. In vitro it behaves as a full and very potent agonist of the CB1 receptor, with an affinity of the order of 3 nM, a potency of 0.33 nM in cyclic AMP inhibition and of 2.3 to 2.5 nM in β-arrestin 2 recruitment, for an efficacy of 239 % of that of the reference JWH-018 in the latter assay; CB2 affinity and activation are not documented. In mice, the molecule produces the characteristic cannabinoid tetrad at doses lower than those of Δ9-THC, induces a place preference at low doses then an aversion at high doses, and causes a withdrawal syndrome precipitated by rimonabant, which signals a potential for physical dependence. No controlled study exists in humans: human data are lacking on effects, pharmacokinetics, tolerance and dependence, and most of what is known comes from forensic toxicology. The ester hydrolysis product, the major metabolite, loses most of its activity at CB1.

Key sources.

History

Source
An entirely synthetic molecule, absent from cannabis as from any living organism: it has no connection with hemp or with cannabidiol products. It circulates as a powder, smoking mixtures, e-cigarette liquids and impregnated papers or blotters; impregnating paper is a commonly used method for bringing synthetic cannabinoids into prisons in some countries. The European monitoring centre counted 770 seizures reported to the early warning system, about 15 % of them made by the police in prisons or other places of detention, in at least six Member States. Detections have also been reported in Asia, New Zealand, the Russian Federation and the United States, where the substance has also been found as an adulterant in products sold as heroin or cannabis (and in Wales).

Origin

Laboratory synthesis

No known biosynthetic pathway: the molecule is produced by no living organism and comes exclusively from organic synthesis. Manufacture is described here only by its chemical class, the indazole-3-carboxamides.

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)

No dedicated article.

References

  1. WHO, Expert Committee on Drug Dependence, 43rd meeting (October 2020): critical review report on MDMB-4en-PINACA (new tab)
  2. EMCDDA (now EUDA), risk assessment report on MDMB-4en-PINACA (2020): notification, market forms, seizures, acute poisonings and deaths (new tab)
  3. Commission Delegated Directive (EU) 2021/802 of 12 March 2021 amending the Annex to Framework Decision 2004/757/JHA (MDMB-4en-PINACA and 4F-MDMB-BICA) (new tab)
  4. ANSM, decision of 9 December 2021 amending the list of substances classified as narcotics (added to annex III, removed from annex IV) (new tab)
  5. ANSM, consolidated list of substances classified as narcotics (updated 16 February 2026): MDMB-4en-PINACA listed by name in annex III (new tab)
  6. UNODC, announcement of the CND decisions (64th session, April 2021): CUMYL-PEGACLONE and MDMB-4en-PINACA in Schedule II of the 1971 Convention, entry into force on 7 December 2021 (new tab)
  7. Krotulski et al., Drug Testing and Analysis, 2021: detection, activity and potential toxicity of the pent-4-ene and but-3-ene analogues including MDMB-4en-PINACA (beta-arrestin 2 recruitment, 25 forensic cases) (new tab)PMID 32997377
  8. Cannaert et al., ACS Chemical Neuroscience, 2020: in vitro CB1 activity of twelve recent agonists, including MDMB-4en-PINACA (new tab)PMID 33253529
  9. Watanabe et al., The AAPS Journal, 2019: biotransformation of MDMB-4en-PINACA in human hepatocytes, liver microsomes, urine and blood (new tab)PMID 31848852
  10. Erol Ozturk and Yeter, Journal of Analytical Toxicology, 2021: in vitro phase I metabolism and detection in human urine (new tab)PMID 32091101
  11. Gu et al., Journal of Pharmaceutical and Biomedical Analysis, 2022: metabolic profiles and screening strategies in human urine and serum (new tab)PMID 35985137
  12. Qiao et al., International Journal of Molecular Sciences, 2025: abuse potential of three indazole-carboxamides, tetrad, place preference and precipitated withdrawal in mice (new tab)PMID 40650186
  13. Simon et al., Toxics, 2023: documented fatal case involving MDMB-4en-PINACA and 4F-ABUTINACA (new tab)PMID 37624178
  14. PubChem, MDMB-4en-PINACA, CID 155804661 (new tab)

Identifiers

Names

IUPAC name
methyl (2S)-3,3-dimethyl-2-[(1-pent-4-enylindazole-3-carbonyl)amino]butanoate
Other names
MDMB-PENINACA · MDMB-PINACA N1-pentyl-4-en isomer · 5CL-ADB-A · ADB-PINACA-A

Identifiers

Formula
C₂₀H₂₇N₃O₃
CAS
2504100-70-1
PubChem CID
155804661(new tab)
InChIKey
LWOCBHBFWNGPGM-QGZVFWFLSA-N
SMILES
CC(C)(C)[C@@H](C(=O)OC)NC(=O)C1=NN(C2=CC=CC=C21)CCCC=C

Machine-readable entry (JSON)

LLM ingestion format: a structured superset of the entry (identifiers, binding, versioned legal status). Full corpus.