white → green3 → black3
Not yet reviewed — this article is pending editorial review by Lyrea.
25I-NBF
2-(4-Iodo-2,5-dimethoxyphenyl)-N-(2-fluorobenzyl)ethanamine
2C-I-NBF, NBF-2C-I, Cimbi-21
hidden
25I-NBF is a synthetic psychedelic of the substituted phenethylamine class, specifically an N-benzylated derivative of 2C-I.1 It acts as a potent partial agonist at the 5-HT2A serotonin receptor2 and has been investigated in radiolabelled form as a potential ligand for brain imaging via positron emission tomography.3 Pharmacological evidence suggests it is considerably less potent than its structural relative 25I-NBOMe.1 It was briefly available as a research chemical before being banned in several countries.
Dosage & Duration
Dosage & Duration not written up yet
Subjective Effects
Subjective Effects not written up yet
Pharmacology
Pharmacodynamics
25I-NBF binds the human 5-HT2A receptor with subnanomolar affinity in the cited in-vitro assay (Ki 0.26 nM).4 Across the N-(2-fluorobenzyl) series, affinity, efficacy, and 5-HT2A/5-HT2C selectivity were generally lower than for the corresponding 2-methoxybenzyl, 2-hydroxybenzyl, or methylenedioxybenzyl series.1 In a separate cell-based comparison, 25I-NBF showed statistically significant signaling bias toward β-arrestin-2 recruitment over miniGαq recruitment relative to LSD.2 These assay findings do not determine a human dose or safety margin.
Pharmacokinetics
In a human-liver-microsome panel that included 25I-NBF, N-benzylated phenethylamines showed substantially higher intrinsic clearance than their parent phenethylamines.56 The authors proposed that low hepatic stability may contribute to low oral activity through first-pass metabolism, but linked that interpretation to anecdotal human reports.5 This in-vitro result does not establish human oral bioavailability, active metabolites, clearance, or half-life for 25I-NBF.
Metabolitesnone documented yet
Dangerous
Highest riskThese combinations are considered extremely harmful and should always be avoided. Reactions to these drugs taken in combination are highly unpredictable and have a potential to cause death.
Unsafe
AvoidThere is considerable risk of physical harm when taking these combinations, they should be avoided where possible.
Caution
Use cautionThese combinations are not usually physically harmful, but may produce undesirable effects, such as physical discomfort or overstimulation. Extreme use may cause physical health issues. Synergistic effects may be unpredictable. Care should be taken when choosing to use this combination.
2C-T-x compounds2C-x compounds5-MeO-xxT tryptaminesCaffeineCannabisDiphenhydramineDOx compoundsMAOIsMDMAMescalineMXE
Tolerance
Tolerance timelines are rules of thumb, not exact schedules, and vary widely between individuals and use patterns.
Cross Tolerance
Serotonergic psychedelics, Other 5-HT2A agonists
Harm Potential
Harm Potential not written up yet
History & Culture
25I-NBF emerged as part of the broader NBOMe and NBF series of N-benzyl phenethylamine derivatives developed for research purposes.31 The compound has been investigated in its carbon-11 radiolabelled form (designated Cimbi-21) as a…
Legality
By Country
United StatesState-level scheduling (Vermont)Citation needed
Not federally scheduled at the national level. The state of Vermont has independently classified 25I-NBF as an illegal substance. Federal prosecution may still be possible under the Federal Analogue Act when sold for human consumption.15
GermanyIllegalNpSG Annex 1
25I-NBF is prohibited as a new psychoactive substance under the NpSG's Annex 1 structural group for compounds derived from 2-phenethylamine. That group permits a phenyl ring with iodine and alkoxy substituents and an N-benzyl-substituted 2-aminoethyl side chain, within a 500-u molecular-mass limit. Section 3 prohibits trade, supply, manufacture, import/export/transit, acquisition, possession, and administration of an Annex 1 substance, subject to the statute's specified exemptions for recognised commercial, industrial, scientific, and authority uses.
JapanIllegalCitation needed
Controlled as a designated substance under Japanese drug control laws.
NetherlandsIllegal (analog/blanket ban)2-fenethylaminederivaat
Opiumwet, lijst IA, stofgroep 110
25I-NBF falls within List IA's substance group for substances derived from 2-phenethylamine. The definition permits a phenyl ring bearing iodine and alkoxy substituents and an N-benzyl substituent with further permitted substitution, which encompasses the N-(2-fluorobenzyl) analogue. Article 2a prohibits import, export, preparation, processing, sale, supply, transport, possession, and manufacture of a substance in a List IA group, subject to the statutory exceptions.
UkraineIllegalTable I List 2
Ukraine's current consolidated List No. 2 of Table I expressly lists 25I-NBF (2C-I-NBF), with the chemical name N-[(2-fluorophenyl)methyl]-2-(4-iodo-2,5-dimethoxyphenyl)ethanamine. List No. 2 is headed as especially dangerous psychotropic substances whose circulation is prohibited; Resolution No. 600 added this named entry and it remains in the current consolidated list.
CanadaIllegalSchedule III
Controlled Drugs and Substances Act, Schedule III, item 357
Canada lists 2C-phenethylamines in Schedule III of the Controlled Drugs and Substances Act. Item 35 covers the specified 1-amino-2-phenylethane structure when the amino group is substituted by benzyl groups, including benzyl groups substituted to any extent; this structural description covers 25I-NBF (N-(2-fluorobenzyl)-2C-I).
HungaryIllegalCitation needed
Classified as a prohibited substance under national drug legislation.
LatviaIllegalCitation needed
Prohibited under national controlled substances legislation.
SwedenSchedule ICitation needed
United KingdomIllegalClass A drug
Misuse of Drugs Act 1971, Schedule 2, Part I, paragraph 1(f)14
25I-NBF is a Class A controlled drug through the Schedule 2 generic definition for compounds structurally derived from the specified phenethylamine derivatives by N-benzyl substitution. The definition covers a benzyl substituent whether or not its phenyl ring is substituted, so the N-(fluorobenzyl) derivative falls within that provision. The Act also controls stereoisomers, esters, ethers, salts, and preparations of the specified substances.
References
Source Pages
Citations
- Synthesis and Structure-Activity Relationships of N-Benzyl Phenethylamines as 5-HT2A/2C Agonists. (n.d.). https://pmc.ncbi.nlm.nih.gov/articles/PMC3963123/1234
- Eline Pottie, Peter Dedecker, & Christophe P. Stove. (December 2020). Identification of psychedelic new psychoactive substances (NPS) showing biased agonism at the 5-HT<sub>2A</sub>R through simultaneous use of β-arrestin 2 and miniGα<sub>q</sub> bioassays. Biochemical Pharmacology, 182. https://doi.org/10.1016/j.bcp.2020.114251123
- Radiosynthesis and in vivo evaluation of a series of substituted 11C-phenethylamines as 5-HT (2A) agonist PET tracers. European Journal of Nuclear Medicine and Molecular Imaging, 38(4), 681–693 (April 2011). https://doi.org/10.1007/s00259-010-1686-8123
- Molecular interaction of serotonin 5-HT2A receptor residues Phe339(6.51) and Phe340(6.52) with superpotent N-benzyl phenethylamine agonists. pubmed.ncbi.nlm.nih.gov (n.d.). https://doi.org/10.1124/mol.106.02872012
- Correlating the metabolic stability of psychedelic 5-HT2A agonists with anecdotal reports of human oral bioavailability. pubmed.ncbi.nlm.nih.gov (n.d.). https://doi.org/10.1007/s11064-014-1253-y12
- Swedish Public Health Agency classification document for 25I-NBF, reproduced by the Swedish Prosecution Authority, document 03814-2015. aklagare.se (n.d.). https://www.aklagare.se/globalassets/dokument/narkotikapreparat/0-9/25i-nbf.pdf1
- Controlled Drugs and Substances Act. laws-lois.justice.gc.ca (n.d.). https://laws-lois.justice.gc.ca/eng/acts/C-38.8/FullText.html1
- Neue-psychoaktive-Stoffe-Gesetz (NpSG), Anlage 1 Nr. 1; § 3 Abs. 1 Nr. 1. gesetze-im-internet.de (n.d.). https://www.gesetze-im-internet.de/npsg/BJNR261510016.html1
- Neue-psychoaktive-Stoffe-Gesetz (NpSG), Anlage 1 Nr. 1; § 3 Abs. 1 Nr. 1. gesetze-im-internet.de (n.d.). https://www.gesetze-im-internet.de/npsg/__3.html1
- Opiumwet, lijst IA, stofgroep 1. wetten.overheid.nl (n.d.). https://wetten.overheid.nl/BWBR0001941/2025-07-011
- Läkemedelsverkets föreskrifter om ändring i Läkemedelsverkets föreskrifter (LVFS 2011:10) om förteckningar över narkotika (HSLF-FS 2015:35). Läkemedelsverket (Swedish Medical Products Agency) (2015). https://lagen.nu/hslf-fs/2015:3512
- Cabinet of Ministers Resolution No. 770 (6 May 2000), Table I, List No. 2. zakon.rada.gov.ua (n.d.). https://zakon.rada.gov.ua/laws/show/770-2000-%D0%BF/print1
- Cabinet of Ministers Resolution No. 770 (6 May 2000), Table I, List No. 2. zakon.rada.gov.ua (n.d.). https://zakon.rada.gov.ua/laws/show/600-2019-%D0%BF1
- Misuse of Drugs Act 1971, Schedule 2, Part I, paragraph 1(f). legislation.gov.uk (n.d.). https://www.legislation.gov.uk/ukpga/1971/38/schedule/21
- 21 U.S. Code § 813 — Treatment of controlled substance analogues. Cornell Legal Information Institute (n.d.). https://www.law.cornell.edu/uscode/text/21/8131
Further Reading
Automated synthesisInformation aggregated and synthesized using an autonomous workflow built by Josie Kins.
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