25I-NBF
25I-NBF is a synthetic psychedelic of the substituted phenethylamine class, specifically an N-benzylated derivative of 2C-I.citation needed It acts as a potent partial agonist at the 5-HT2A serotonin receptor and has been investigated in radiolabelled form as a potential ligand for brain imaging via positron emission tomography. Pharmacological evidence suggests it is considerably less potent than its structural relative 25I-NBOMe. It was briefly available as a research chemical before being banned in several countries.
Dosage & Duration
Subjective Effects
Pharmacology
Pharmacodynamics
25I-NBF binds the human 5-HT2A receptor with subnanomolar affinity in the cited in-vitro assay (Ki 0.26 nM).1 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.2 In a separate cell-based comparison, 25I-NBF showed statistically significant signaling bias toward β-arrestin-2 recruitment over miniGαq recruitment relative to LSD.citation needed 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.citation needed 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.3 This in-vitro result does not establish human oral bioavailability, active metabolites, clearance, or half-life for 25I-NBF.
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.
Tolerance
Tolerance timelines are rules of thumb, not exact schedules, and vary widely between individuals and use patterns.
Serotonergic psychedelics, Other 5-HT2A agonists
Harm Potential
History & Culture
25I-NBF emerged as part of the broader NBOMe and NBF series of N-benzyl phenethylamine derivatives developed for research purposes.citation needed The compound has been investigated in its carbon-11 radiolabelled form (designated Cimbi-21) as a potential ligand for positron…
Legality
By Country
References
Source Pages
Citations
- 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.106.0287201
- Synthesis and Structure-Activity Relationships of N-Benzyl Phenethylamines as 5-HT2A/2C Agonists. (n.d.). https://pmc.ncbi.nlm.nih.gov/articles/PMC3963123/1
- 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-y1
- 薬物乱用防止に関する情報 — Ministry of Health, Labour and Welfare. mhlw.go.jp (n.d.). https://www.mhlw.go.jp/stf/seisakunitsuite/bunya/kenkou_iryou/iyakuhin/yakubuturanyou/index.html1
- 指定薬物名称・構造式一覧 (current as of 27 August 2026). mhlw.go.jp (n.d.). https://www.mhlw.go.jp/content/11120000/001743040.pdf1
- 指定薬物を指定する省令が公布されました — MHLW. mhlw.go.jp (n.d.). https://www.mhlw.go.jp/seisakunitsuite/bunya/kenkou_iryou/iyakuhin/yakubuturanyou/oshirase/20150522.html1
- 新たに指定された指定薬物の名称 (MHLW, 22 May 2015). mhlw.go.jp (n.d.). https://www.mhlw.go.jp/seisakunitsuite/bunya/kenkou_iryou/iyakuhin/yakubuturanyou/oshirase/dl/20150522.pdf1
- 医薬品、医療機器等の品質、有効性及び安全性の確保等に関する法律 (PMD Act). mhlw.go.jp (n.d.). https://www.mhlw.go.jp/web/t_doc?dataId=81004000&dataType=01
- About the Penalties for Drug Offenses in Japan — Designated Substances. mhlw.go.jp (n.d.). https://www.mhlw.go.jp/content/11120000/001682850.pdf1
- 麻薬及び向精神薬取締法 別表第1 (MHLW narcotics schedule). mhlw.go.jp (n.d.). https://www.mhlw.go.jp/content/11120000/001685509.pdf1
Further Reading
Article Status
Step 1 · Automated synthesisAn autonomous workflow built by Josie Kins compiled this article's foundation from information published across the web.
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Recent changes7 human edits · latest
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24 January 2026
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
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