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2C-T-21

4-(2-fluoroethylthio)-2,5-dimethoxyphenethylamine

6Node page

what any key link opens

psx:substance/2c-t-21/proposal/timeline/7267da3f-e1cd-44f7-8132-7b7f6a8b86a8

proposal2026-05-11recordapproved

derived from · upstream

none recorded

feeds · downstream

Closure of psx:substance/2c-t-21/proposal/timeline/7267da3f-e1cd-44f7-8132-7b7f6a8b86a8: 0 upstream, 1 downstream.

psx:substance/2c-t-21/proposal/timeline/7267da3f-e1cd-44f7-8132-7b7f6a8b86a8
└─ derived_from  value/timeline/oral/onset@1

indented by distance from this node, not by parentage

1Provenance card

the boundary, as counts

Sources

1711 with DOI

1 strong · 12 moderate · 4 weak

Compilations

12026-05-11T03:15:23.078Z

pipeline-v5 · prompt hash not recorded — run predates 2026-09

Decisions

29last ruled 2026-06-04

0 awaiting a ruling

Issued documents

62026-10-19T20:29:27.923Z

notice · info card · emergency

Searches

173 with no results

queries and counts on the build

Claims checked

4436 supported

36 supported · 8 not

Correspondence

0received

consent field ships in Phase 4

Edges

168

derivations recorded for this entity

Complete over 17 sources, 1 compilation, and 29 decisions.Not here: the private journal (never).Working material — drafts, discards, unsupported claims — is listed below and readable on the working page.Cite: psychedex.org/substances/2c-t-21/archive

2Build

one panel per compilation run

generation run 2026-05-11

72 min completedmodel pipeline-v5plan not recordedrun/c974ce21…

Selection

results seen70
selected by the model32
consumed as sources17

Verification

claims checked44
supported31
partially supported5
not supported0
inconclusive8
  • record
  • seen / partial
  • working

The model's own caveats

5 further caveats recorded as free text — readable on the working page

Reproduce

inputs
17 source keys (listed under Sources)
plan
not recorded — template version, prompt hash and git SHA are written from 2026-09 onward
model
pipeline-v5
streams
none — agent transcripts are persisted from 2026-09 onward
17 searches — query, source, results, what was kept and why
17 searches for this run
#sourcequeryseenkeptrationale
1PubMed2C-T phenethylamine psychedelic thio substituent serotonin receptor11Directly studies the 2C-T subclass to which 2C-T-21 belongs; uses HTR as psychedelic activity proxy
2PubMed · absence2C-T-21 psychedelic phenethylamine00Null result indicates sparse published data; must rely on class-level and analog literature
3ClinicalTrials.gov · absence2C-T-21 phenethylamine psychedelic00Confirms no clinical trial activity for this compound
4OpenAlex4-thio-substituted 2,5-dimethoxyphenethylamine structure activity relationship psychedelic105All relevant to 2C-T class pharmacology, toxicology, and SAR; provide class-level data applicable to 2C-T-21
5PubChem2C-T-2111Primary chemical identity data for 2C-T-21; confirms seed data systematic name and adds formula, weight, InChIKey
6PubMedWagmann 2C-T-7-FLY metabolism CYP isoenzyme MAO11Provides CYP enzyme and MAO involvement data for a closely related 2C-T-series compound
7PubChem2C-T-21 CID 4434997214Primary source for chemical identity data
8PubMedmonoamine receptor interaction profiles 4-thio-substituted phenethylamines 2C-T drugs11Directly characterizes receptor binding for 2C-T series which includes or is closely related to 2C-T-21
9Web search2C-T-21 monoamine oxidase MAO inhibitor MAOI phenethylamine safety101Direct evidence of MAO inhibitory activity for 2C-T-21 from named compound testing
10Web search2C-T-21 PIHKAL Shulgin fluoroethylthio synthesis103Primary historical source for 2C-T-21 discovery, dosing, and first human effect descriptions
11PubMed CentralHalberstadt 2023 2C-T-21 full text PMC981619413Primary source for 2C-T-21 specific receptor binding and in vivo potency data
12Web search2C-T-21 legal status scheduling DEA UK Canada Germany104Legal status information for major jurisdictions
13Web searchHalberstadt 2023 4-thio 2C-T-21 fluoroethylthio head-twitch fourfold potency51Confirms critical SAR finding for 2C-T-21
14ClinicalTrials.gov · absence2C-T-21 phenethylamine psychedelic00Confirms complete absence of clinical trial activity
15ErowidPIHKAL entry #49 2C-T-2113Primary source for historical dosing and effect descriptions
16Web search2C-T-21 SMILES molecular structure ChemSpider fluoroethylthio102Chemical structure confirmation for SMILES field
17OpenAlex2C-T-2 serotonin 5-HT2A receptor binding affinity Ki hallucinogen phenethylamine82Receptor pharmacology and cardiovascular safety context
44 claims by section — every cited sentence, checked against its source
safety11 · 10 ok
  • Dean et al. documented at least five deaths attributed to 2C-series drugs, with excited delirium as a characteristic terminal presentation; sympathomimetic toxicity (tachycardia, hypertension, hyperthermia) and serotonin toxicity are the primary clinical syndromes observed in 2C intoxicationsupported

    At least 5 deaths reported; excited delirium common among fatalities. Sympathomimetic and serotonin toxicity presentations. s13181-013-0295-x

  • Schifano et al. reported one death from mono-intoxication with the structurally analogous 2c-t-7 (propylthio vs. fluoroethylthio at C4) — the closest published precedent for lethal risk in the 2C-T subclass.supported

    one death in USA from mono-intoxication documented pmid:16272191

  • Acute cardiovascular effects — blood pressure elevation and heart rate increase — have been documented in controlled human studies of the related compound 2c-b and are expected for 2C-T-21 based on serotonergic and sympathomimetic class pharmacology.supported

    Increased BP and HR, euphoria, perceptual changes. fphar.2018.00206

  • Acute cardiovascular effects — blood pressure elevation and heart rate increase — have been documented in controlled human studies of the related compound 2c-b and are expected for 2C-T-21 based on serotonergic and sympathomimetic class pharmacology.supported

    Acute sympathomimetic effects documented. s43440-023-00539-4

  • Claim in safety — inconclusiveinconclusiveworking →

  • MAO-A and MAO-B are the primary metabolic enzymes for the 2C-T series, so exogenous MAOI co-administration would impair 2C-T-21 clearance while simultaneously producing additive MAO inhibition from 2C-T-21's own inhibitory activitysupported

    MAO-A and MAO-B are major enzymes in deamination. 2C compounds susceptible to drug-drug interactions with MAO inhibitors. j.bcp.2006.09.033

  • MAO-A and MAO-B are the primary metabolic enzymes for the 2C-T series, so exogenous MAOI co-administration would impair 2C-T-21 clearance while simultaneously producing additive MAO inhibition from 2C-T-21's own inhibitory activitysupported

    2C-T-21 explicitly named. 13 showed MAO-A inhibition, 11 showed MAO-B inhibition. dta.2494

  • Chronic SSRI administration may also attenuate psychedelic effects through 5-HT₂A receptor downregulation.supported

    Chronic SSRI/SNRI administration attenuates LSD effects in humans, attributed to 5-HT2A receptor downregulation. 0893-133x(95)00145-4

  • Cannabis may potentiate psychedelic intensity in a dose-dependent manner, increasing the probability of overwhelming or difficult experiences.supported

    Cannabis combined with classic serotonergic psychedelics associated with more intense psychedelic experience (MEQ, ASC-Vis, EDI scores) in dose-dependent manner. s00213-021-05999-1

  • The dependence of 2C-T-21 metabolism on MAO enzymes combined with its own MAO inhibitory activity creates a pharmacokinetic-pharmacodynamic trap: the drug cannot be cleared while simultaneously amplifying monoaminergic activity.supported

    MAO-A and MAO-B are major enzymes in deamination. 2C compounds susceptible to drug-drug interactions with MAO inhibitors. j.bcp.2006.09.033

  • The dependence of 2C-T-21 metabolism on MAO enzymes combined with its own MAO inhibitory activity creates a pharmacokinetic-pharmacodynamic trap: the drug cannot be cleared while simultaneously amplifying monoaminergic activity.supported

    2C-T-21 explicitly named. 13 showed MAO-A inhibition, 11 showed MAO-B inhibition. MAO inhibition pharmacological contribution cannot be excluded. dta.2494

pharmacology10 · 7 ok
  • Claim in pharmacology — inconclusiveinconclusiveworking →

  • Halberstadt et al. reported a 5-HT₂A Ki of 27 nM for 2C-T-21, placing it within the 1–54 nM affinity range observed across the 2C-T seriessupported

    5-HT2A Ki 1-54 nM j.neuropharm.2017.07.012

  • Claim in pharmacology — inconclusiveinconclusiveworking →

  • The absence of significant monoamine transporter activity (DAT/NET/SERT Ki > 4,000 nM across the 2C-T class) distinguishes this pharmacological profile from entactogen-class phenethylamines such as MDMA.supported

    no monoamine transporter activity (Ki > 4000 nM) j.neuropharm.2017.07.012

  • Trace amine-associated receptor 1 (TAAR1) binding has been characterized for the 2C-T series as a class (Ki range 5–68 nM), though a discrete Ki value for 2C-T-21 specifically has not been publishedsupported

    rat TAAR1 5-68 nM j.neuropharm.2017.07.012

  • Wagmann et al. demonstrated that 2C-T-21 inhibits both MAO-A and MAO-B in vitro, testing the compound directly among 12 2C-series substancessupported

    2C-T-21 explicitly named. 13 showed MAO-A inhibition, 11 showed MAO-B inhibition. dta.2494

  • Claim in pharmacology — inconclusiveinconclusiveworking →

  • Theobald and Maurer identified MAO-A and MAO-B as the primary enzymes responsible for oxidative deamination of 2C-T-2 and 2C-T-7, converting the primary amine to the corresponding aldehyde; CYP2D6 contributes to a lesser extentsupported

    MAO-A and MAO-B are major enzymes in deamination. CYP2D6 minor role for 2C-T-2 and 2C-T-7. j.bcp.2006.09.033

  • For the structurally related 2C-T-7-FLY, Wagmann et al. identified CYP2D6, CYP3A4, and FMO3 as phase I enzymes, with NAT1/NAT2 catalyzing N-acetylationsupported

    Phase I: CYP2D6, 3A4, FMO3; N-acetylation by NAT1/NAT2. dta.2675

  • The dependence of 2C-T-21 metabolism on MAO enzymes has direct safety implications: concurrent administration of exogenous MAO inhibitors would substantially impair clearance, leading to elevated plasma concentrations and prolonged effects.supported

    2C compounds susceptible to drug-drug interactions with MAO inhibitors. j.bcp.2006.09.033

comparative-pharmacology7 · 6 ok
  • It is the most extensively studied member of the 2C-T series, with one documented fatality from mono-intoxication and published in vitro neurotoxicity datapartially supported

    one death in USA from mono-intoxication documented pmid:16272191

  • It is the most extensively studied member of the 2C-T series, with one documented fatality from mono-intoxication and published in vitro neurotoxicity datasupported

    In vitro neurotoxicity study of 2C-T-2, 2C-T-4, 2C-T-7 and NBOMe counterparts in SH-SY5Y cells. jox14020044

  • Claim in comparative-pharmacology — inconclusiveinconclusiveworking →

  • Despite this potency reduction, both compounds share a similar 5-HT₂A affinity range (2C-T-2 falls within the 1–54 nM class range)supported

    5-HT2A Ki 1-54 nM j.neuropharm.2017.07.012

  • Both compounds share MAO-dependent primary metabolism and produce extended-duration psychedelic effects (2C-T-7: 8–15 hours; 2C-T-21: 7–12 hours)partially supported

    MAO-A and MAO-B are major enzymes in deamination. j.bcp.2006.09.033

  • 2c-b replaces the thioether entirely with a bromine atom at C4, producing a shorter-duration (4–6 hours), more dose-forgiving compound with controlled human pharmacological datapartially supported

    Observational study of 2C-B (10, 15, 20 mg oral). Tmax of 2C-B ~1h. fphar.2018.00206

  • The thioether substituent also introduces MAO inhibitory activity absent in 2C-B, creating a dual-action pharmacological profile unique to the 2C-T subclass.supported

    17 drugs tested (12 2Cs including 2C-T-21, plus 5 FLY analogs). 13 showed MAO-A inhibition, 11 showed MAO-B inhibition. dta.2494

summary7 · 6 ok
  • Halberstadt et al. reported compound-specific 5-HT₂A binding data (Ki = 27 nM) and in vivo head-twitch response potency in 2023, while Wagmann et al. confirmed direct MAO-A and MAO-B inhibitory activity in 2019partially supported

    HTR dose-response studies with twelve different 4-thio-substituted phenylalkylamines conducted in male C57BL/6J mice. s00213-022-06279-2

  • Halberstadt et al. reported compound-specific 5-HT₂A binding data (Ki = 27 nM) and in vivo head-twitch response potency in 2023, while Wagmann et al. confirmed direct MAO-A and MAO-B inhibitory activity in 2019supported

    17 drugs tested (12 2Cs including 2C-T-21, plus 5 FLY analogs). 2C-T-21 explicitly named. 13 showed MAO-A inhibition, 11 showed MAO-B inhibition. dta.2494

  • Claim in summary — inconclusiveinconclusiveworking →

  • The compound also inhibits MAO-A and MAO-B at micromolar concentrations — a dual property with significant drug interaction implications.supported

    MAO-A IC50 10-125 µM (7 drugs); MAO-B IC50 1.7-180 µM (9 drugs). MAO inhibition pharmacological contribution cannot be excluded. dta.2494

  • No LD₅₀ or therapeutic index data exist for 2C-T-21; toxicity assessments derive entirely from structural analogy to the 2C-T class, where at least one fatality from 2c-t-7 and five class-level deaths have been documentedsupported

    2C-T-7 market review; first synthesized 1986; one death in USA from mono-intoxication documented. pmid:16272191

  • No LD₅₀ or therapeutic index data exist for 2C-T-21; toxicity assessments derive entirely from structural analogy to the 2C-T class, where at least one fatality from 2c-t-7 and five class-level deaths have been documentedsupported

    At least 5 deaths reported; excited delirium common among fatalities. s13181-013-0295-x

  • The confirmed MAO inhibitory activity creates a critical contraindication with exogenous MAO inhibitors and serotonergic medicationssupported

    MAO inhibition pharmacological contribution cannot be excluded. dta.2494

receptor-pharmacology4 · 3 ok
  • Claim in receptor-pharmacology — inconclusiveinconclusiveworking →

  • The most detailed receptor interaction data for 2C-T-21 come from Halberstadt et al., who characterized 12 4-thio-substituted 2,5-dimethoxyphenylalkylamines using radioligand binding and functional assays.partially supported

    HTR dose-response studies with twelve different 4-thio-substituted phenylalkylamines conducted in male C57BL/6J mice. s00213-022-06279-2

  • Luethi et al. characterized the broader 2C-T drug series, including compounds with fluoroethylthio substitution, providing class-level context for 2C-T-21:supported

    Characterized monoamine receptor and transporter interaction profiles of 2C-T drug series including fluoroethylthio derivatives. j.neuropharm.2017.07.012

  • Wagmann et al. tested 2C-T-21 directly for monoamine oxidase inhibition, confirming activity at both MAO-A and MAO-Bsupported

    2C-T-21 explicitly named. 13 showed MAO-A inhibition, 11 showed MAO-B inhibition. dta.2494

pharmacokinetic-detail3 · 3 ok
  • CYP2D6 contributes as a minor phase I pathwaysupported

    CYP2D6 minor role for 2C-T-2 and 2C-T-7. j.bcp.2006.09.033

  • For the conformationally restricted analog 2C-T-7-FLY, Wagmann et al. identified additional phase I enzymes (CYP3A4, FMO3) and phase II N-acetylation via NAT1/NAT2supported

    Phase I: CYP2D6, 3A4, FMO3; N-acetylation by NAT1/NAT2. dta.2675

  • A broader metabolic review by Meyer confirmed MAO and CYP involvement in 2C-T-2 and 2C-T-7 clearance.supported

    Reviews metabolism of 2C compounds including 2C-T-2 and 2C-T-7. CYP and MAO isoenzyme-dependent metabolism. pmid:20540700

neuroscience2 · 1 ok
  • Claim in neuroscience — inconclusiveinconclusiveworking →

  • The additional MAO inhibitory activity of 2C-T-21 introduces a secondary monoaminergic modulation absent in classical psychedelics such as psilocybin or LSDsupported

    2C-T-21 explicitly named. 13 showed MAO-A inhibition, 11 showed MAO-B inhibition. MAO inhibition pharmacological contribution cannot be excluded. dta.2494

3Sources

17 consumed · sorted by year · feeds = sections resting on it

Sources
yearsourcetierstatusfeeds
20242C-T-21 (hydrochloride) - Cayman Chemical Product 31133Cayman Chemicalurl:d9319ff7815c3460weakconsumedcited only
2024Erowid Experience Vaults: 2C-T-21Erowidurl:4b8f73d3debc07edweakconsumedcited only
2024Mechanistic Insights into the Neurotoxicity of 2,5-Dimethoxyphenethylamines (2C) and Corresponding N-(2-methoxybenzyl)phenethylamine (NBOMe) DrugsGil-Martins E, Cagide-Fagin F, Martins D, Borer A, Barbosa DJ, Fernandes C, Chavarria D, Remiao F, Borges F, Silva R · Journal of Xenobioticsdoi:10.3390/jox14020044moderateconsumed2 sections
2023Cardiovascular safety of psychedelic medicine: current status and future directionsWsół A · Pharmacological Reportsdoi:10.1007/s43440-023-00539-4moderateconsumed1 section
2023Use of the head-twitch response to investigate the structure-activity relationships of 4-thio-substituted 2,5-dimethoxyphenylalkylaminesHalberstadt AL, Luethi D, Hoener MC, Trachsel D, Brandt SD, Liechti ME · Psychopharmacologydoi:10.1007/s00213-022-06279-2moderateconsumed5 sections
2023Use of the head-twitch response to investigate the structure-activity relationships of 4-thio-substituted 2,5-dimethoxyphenylalkylamines (full text)Halberstadt AL, Luethi D, Hoener MC, Trachsel D, Brandt SD, Liechti ME · Psychopharmacologyurl:4575f12f399e8ed3weakconsumedcited only
2022Psychedelic experience dose-dependently modulated by cannabis: results of a prospective online surveyKuc J, Kettner H, Rosas F, Erritzoe D, Haijen E, Kaelen M, Nutt D, Carhart-Harris RL · Psychopharmacologydoi:10.1007/s00213-021-05999-1moderateconsumed1 section
2019Interactions of phenethylamine-derived psychoactive substances of the 2C-series with human monoamine oxidasesWagmann L, Brandt SD, Stratford A, Maurer HH, Meyer MR · Drug Testing and Analysisdoi:10.1002/dta.2494moderateconsumed6 sections
2019Phenethylamine-derived new psychoactive substances 2C-E-FLY, 2C-EF-FLY, and 2C-T-7-FLY: Investigations on their metabolic fate including isoenzyme activities and their toxicological detectability in urine screeningsWagmann L, Hempel N, Richter LHJ, Brandt SD, Stratford A, Meyer MR · Drug Testing and Analysisdoi:10.1002/dta.2675moderateconsumed2 sections
2018Acute Pharmacological Effects of 2C-B in Humans: An Observational StudyPapaseit E, Farre M, Perez-Mana C, Torrens M, Ventura M, Pujadas M, de la Torre R, Gonzalez D · Frontiers in Pharmacologydoi:10.3389/fphar.2018.00206moderateconsumed2 sections
2018Monoamine receptor interaction profiles of 4-thio-substituted phenethylamines (2C-T drugs)Luethi D, Trachsel D, Hoener MC, Liechti ME · Neuropharmacologydoi:10.1016/j.neuropharm.2017.07.012moderateconsumed3 sections
20132C or Not 2C: Phenethylamine Designer Drug ReviewDean BV, Stellpflug SJ, Burnett A, Engebretsen KM · Journal of Medical Toxicologydoi:10.1007/s13181-013-0295-xstrongconsumed2 sections
2010Metabolism of designer drugs of abuse: an updated reviewMeyer MR, Maurer HH · Current Drug Metabolismpmid:20540700moderateconsumed1 section
2007Identification of monoamine oxidase and cytochrome P450 isoenzymes involved in the deamination of phenethylamine-derived designer drugs (2C-series)Theobald DS, Maurer HH · Biochemical Pharmacologydoi:10.1016/j.bcp.2006.09.033moderateconsumed4 sections
2005New trends in the cyber and street market of recreational drugs? The case of 2C-T-7 ('Blue Mystic')Schifano F, Deluca P, Agosti L, Martinotti G, Corkery JM, et al. · Journal of Psychopharmacologypmid:16272191moderateconsumed3 sections
1996Chronic administration of serotonergic antidepressants attenuates the subjective effects of LSD in humans.Bonson KR, Buckholtz JW, Murphy DL · Neuropsychopharmacologydoi:10.1016/0893-133x(95)00145-4moderateconsumed1 section
1991PiHKAL Entry #49: 2C-T-21Shulgin ATurl:d67f0d5f0a2ab959weakconsumedcited only
—Searched ClinicalTrials.gov for "2C-T-21 phenethylamine psychedelic" — no resultsabsenceno results—
—Searched ClinicalTrials.gov for "2C-T-21 phenethylamine psychedelic" — no resultsabsenceno results—
—Searched PubMed for "2C-T-21 psychedelic phenethylamine" — no resultsabsenceno results—

4Docket

one filing per activity — decisions, correspondence, reports

  1. 0012026-05-11revisionRevision 1

    Initial LLM generation (v5 pipeline, wiki, prose phase)

    psx:substance/2c-t-21/version/1
  2. 0022026-06-04proposal27 value proposals approved together

    one review action inferred from a shared reviewer and instant — the graph records one activity per proposal

    27 items in this filing

    • dose_tier · light
    • dose_tier · common
    • dose_tier · strong
    • dose_tier · heavy
    • timeline · oral · onset
    • timeline · oral · come_up
    • timeline · oral · peak
    • timeline · oral · resolution
    • timeline · oral · afterglow
    • toxicity
    • dependence · full
    • withdrawal
    • tolerance
    • dosage · oral
    • duration · oral · onset
    • duration · oral · peak
    • duration · oral · offset
    • duration · oral · total
    • duration · oral · aftereffects
    • contraindication · other
    • contraindication · psychiatric
    • contraindication · other
    • contraindication · cardiovascular
    • contraindication · hepatic
    • contraindication · pregnancy_breastfeeding
    • contraindication · neurological
    psx:substance/2c-t-21/proposal/dose_tier/85a2dbe2-aa52-4c49-b288-4d1f54a0b920
  3. 0032026-06-04publicationPublication — backfill

5Issued documents

what the notice, info card and emergency page said, by hash

Issued documents
documentcontent hashissuedfrom versionsuperseded
emergencyc15c760aabf6f0fcf5b6fc6b…2026-10-19 20:29Revision 1current
info_cardc116e5c5dbff5175f85fde2f…2026-10-19 20:29Revision 1current
notice46fd09872c29386b79973bba…2026-10-19 20:29Revision 1current
emergency3f0909c25c714d225b4bb3e3…2026-09-04 04:27Revision 1superseded2026-10-19
info_card234b7cfdd4a121a71ab46294…2026-09-04 04:27Revision 1superseded2026-10-19
notice969f37c2ea46a13f684eec76…2026-09-04 04:27Revision 1superseded2026-10-19