JWH-203.

JWH-203 belongs to a branch of the Huffman series that answered a precise question: is the bulky naphthalene system of the first cannabimimetic indoles indispensable for recognition by the cannabinoid receptors. The phenylacetylindoles replace the direct ketone with an acetyl bridge, that is, one more methylene between the carbonyl and a simple benzene ring, and they remain active. JWH-203 is the 2-chlorinated analogue. ChEMBL reports a Ki of 8.0 nM at CB1 (rat brain) and 7.0 nM at CB2 (cloned human) for it, from Huffman et al. (2005); in rats, it fully substitutes for Δ9-THC in drug discrimination (Gatch and Forster, 2014). Nothing is published on TRPV1, GPR55, PPARγ or 5-HT1A, and there is no controlled study in humans: neither dose, tolerance nor dependence is characterised. The molecule is among the twenty-two synthetic cannabinoids that a validated method looks for in the hair of consumers of Spice-type products, where two to six substances of this class are found in the same segment (Hutter et al., 2012). It is classified as a narcotic in France under its own name.

Source

An entirely synthetic molecule, absent from hemp and from any living organism. It was identified in seized products, with RCS-4, AM-2201 and JWH-210 (Denooz et al., J Anal Toxicol 2013), and it figures among the compounds most commonly found in K2/Spice-type products tested in 2014 (Gatch and Forster) as well as in the lists of the EUDA and of UNODC recording the synthetic cannabinoids reported (Zangani et al., 2020). None of this relates to hemp or to cannabidiol products.

No known biosynthetic pathway: the molecule is produced by no plant or living organism. It belongs solely to synthetic chemistry, described here by chemical class only.

European Union

The substance is not listed in the Annex to Council Framework Decision 2004/757/JHA (consolidated version of 12 January 2026), which lists the new psychoactive substances controlled at European Union level; control is a matter for national law. It appears in the lists of the EUDA and of UNODC recording the synthetic cannabinoids reported (Zangani et al., 2020), which is monitoring and not control. It does not appear in the schedules of the 1971 Convention on Psychotropic Substances (green list of the INCB, 35th and 36th editions). France cites this molecule by name in annex IV of its list.

France

JWH-203 is classified as a narcotic in France, and cited under its own name. The ANSM consolidated list (updated 16 February 2026) cites it in annex IV, under the entry « JWH-203 ou 1-pentyl-3-(2-chlorophenylacetyl) indole », as an example (« notamment ») of the generic family of the « indol-3-yl methanones »: a substituent on the indole nitrogen of the alkyl, haloalkyl, cycloalkylmethyl or related type, and a naphthyl, benzyl, phenyl, cyclopropyl or adamantyl group, substituted or not, on the carbon of the methanone bridge. The 2-chlorobenzyl of JWH-203 meets this definition. According to a reading of the decree of 3 October 2017 (JORF of 10 October 2017), which replaces the text of annex IV, JWH-203 was added to the list of examples on that date (the generic family itself dates from the decree of 31 March 2017). The clause on tetrahydrocannabinols (annex III since the decision of 6 February 2026) does not apply. Production, possession, transfer, transport and use fall under the criminal law on narcotics.

Sources: EUR-Lex, UNODC, CND, ANSM, IUPHAR/BPS, ChEBI, EUDA. Our method.

Family

Synthetic CB receptor agonist › New psychoactive substance

Class

phenylacetylindole

Verification

Classification, sources and binding values checked on 20 October 2026; text read against its sources and Wikipedia.

Wikipedia (English)

JWH-203 (new tab)

Article paired by the molecule's structure (InChIKey), revision read on 19 October 2026. Read as a second opinion, never cited as a source.

1. 1Huffman JW, Szklennik PV, Almond A, Bushell K, Selley DE, He H, et al. 1-Pentyl-3-phenylacetylindoles, a new class of cannabimimetic indoles. Bioorg Med Chem Lett. 2005;15:4110-4113 (Ki values from ChEMBL) (new tab)PMID 16005223
2. 2Gatch MB, Forster MJ, Delta-9-tetrahydrocannabinol-like discriminative stimulus effects of compounds commonly found in K2/Spice, Behavioural Pharmacology, 2014 (full substitution for THC and locomotor depression) (new tab)PMID 25325289
3. 3Denooz R, Vanheugen JC, Frederich M, de Tullio P, Charlier C. Identification and structural elucidation of four cannabimimetic compounds (RCS-4, AM-2201, JWH-203 and JWH-210) in seized products. J Anal Toxicol. 2013;37:56-63 (new tab)PMID 23339188
4. 4Hutter M, Kneisel S, Auwärter V, Neukamm MA. Determination of 22 synthetic cannabinoids in human hair by liquid chromatography-tandem mass spectrometry. J Chromatogr B. 2012;903:95-101 (new tab)PMID 22835826
5. 5Mercier G, Mohamed KA, Zagzoog A, et al. In vitro pharmacological activity of twenty-eight synthetic cannabinoid receptor agonists at the type 1 and 2 cannabinoid receptors. Neurochem Int. 2025 (abstract: class toxicities) (new tab)PMID 40876783
6. 6Zangani C et al. The e-Psychonauts' 'Spiced' World: assessment of the synthetic cannabinoids' information available online. Curr Neuropharmacol 2020 (JWH-203 in the UNODC, EUDA and NPSFinder lists) (new tab)PMID 32116194
7. 7ANSM, consolidated list of substances classified as narcotics, updated 16 February 2026 (annex IV, « indol-3-yl methanone » family, JWH-203 cited as an example) (new tab)
8. 8Légifrance, order of 3 October 2017 amending the order of 22 February 1990 setting the list of substances classified as narcotics, annex IV (JORF of 10 October 2017) (new tab)
9. 9PubChem, Compound Summary CID 44397500, JWH-203 (new tab)

SMILES

CCCCCN1C=C(C2=CC=CC=C21)C(=O)CC3=CC=CC=C3Cl

Machine-readable entry (JSON)

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