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25I-NBF

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Dosage & Duration
Subjective Effects
Harm Potential
25I-NBF molecule structure25I-NBF molecule structure
2-(4-Iodo-2,5-dimethoxyphenyl)-N-(2-fluorobenzyl)ethanamine
2C-I-NBF, NBF-2C-I, Cimbi-21
Psychoactive Class
hidden

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

Dosage & Duration not written up yet

Subjective Effects

Subjective Effects not written up yet

Reagent Testing

Expected colorimetric results for common reagent tests. Colors show reaction change over 1–2 minutes.

Marquis(MQ)
white → green3 → black3
Mecke(ME)
white → brown2 → black3
Mandelin(MD)
yellow2 → orange2 → black3
Liebermann(LB)
white → orange2 → black3
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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.

Metabolitesnone documented yet

Interactions

Dangerous

Highest risk

These 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

Avoid

There is considerable risk of physical harm when taking these combinations, they should be avoided where possible.

AmphetaminesCocaineDXMTramadol

Caution

Use caution

These 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
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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.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

Illegal9
Canada flagCanadaIllegal
Germany flagGermanyIllegal
Hungary flagHungaryIllegal
Japan flagJapanIllegal
Latvia flagLatviaIllegal
Netherlands flagNetherlandsIllegal (analog/blanket ban)
Sweden flagSwedenSchedule I
Ukraine flagUkraineIllegal
United Kingdom flagUnited KingdomIllegal
Not scheduled1
United States flagUnited StatesState-level scheduling (Vermont)

References

Source Pages

  1. Bluelight: The Big & Dandy 25I-NBF Thread
  2. PsychonautWiki: 25x-NBOMe
  3. TripSit Drug Profile: 25I-NBF
  4. Wikipedia

Citations

  1. 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
  2. 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
  3. 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
  4. 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
  5. 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
  6. 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
  7. 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
  8. 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
  9. About the Penalties for Drug Offenses in Japan — Designated Substances. mhlw.go.jp (n.d.). https://www.mhlw.go.jp/content/11120000/001682850.pdf1
  10. 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

  1. Hansen et al. (2014) - High-potency N-benzyl phenethylamines: structure-activity at 5-HT2A receptors

Article Status

  • Josie Kins avatar
    Step 1 · Automated synthesis

    An autonomous workflow built by Josie Kins compiled this article's foundation from information published across the web.

  • Step 2 · First-pass reviewPending

    Not yet reviewed: this article is pending editorial review by Lyrea.

  • Step 3 · Citation reviewPending

    No one has reviewed this article's citations yet. That second pass checks each claim against the source it cites.

Recent changes7 human edits · latest

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24 January 2026

  1. Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more

  2. Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more

  3. Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more

  4. Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more

  5. Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more

  6. Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more

  7. Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more

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