white → orange1
dose.wiki is still in beta. Entries may contain inaccuracies and/or lack citations. See our docs for more info.
2C-T-21
4-(2-Fluoroethylthio)-2,5-dimethoxyphenethylamine
Aurora
2C-T-21 is a synthetic psychedelic of the substituted phenethylamine class and a member of the 2C-x family.citation needed First described by Alexander Shulgin and colleagues in 1991 and later documented in his book PiHKAL, it was derived from the systematic modification of the mescaline molecule. Distinguished by its fluoroethyl thioether substitution at the 4-position,12 it remains a relatively obscure research chemical with limited documentation regarding its effects and safety profile.
Dosage & Duration
Dosage
Doses are population estimates that vary widely between individuals.
Threshold~3 mg
Light3-5 mg
Moderate5-8 mg
Strong8-12 mg
Heavy12+ mg
This substance should only be taken orally. Other routes of administration pose significant risks of serious adverse reactions, including severe nausea and vomiting, dangerous physiological effects, and potentially life-threatening outcomes.
Duration
Onset30-90 minutes
Peak3-4 hours
Offset2-3 hours
After Effects2-4 hours
Total7-12 hours
Subjective Effects
Legacy content. A statistically backed ontology from Mindstate Design Labs is coming soon.
The experience comes on very gradually, typically taking an hour to become noticeable and reaching full intensity by the end of the second hour. It is generally described as a gentle, warm, and non-threatening material characterized by clear thinking, enhanced communication, and a growing sense of closeness with others. Visuals are comparatively subdued, and the compound is repeatedly noted as easy on the body, though higher doses bring a considerable push of energy that can feel restless.
Physical
The body feeling is warm and energetic, generally safe and comfortable, though higher doses produce a push of energy accompanied by restlessness. Chills can occur during onset, along with yawning and ear-popping; appetite effects vary, with decreased appetite reported by some and unusual hunger by others.
Cognitive
The headspace is notably clear and communicative, with empathy, insight, and a softening of the ego rather than dramatic alterations of consciousness. Mood is generally warm and peaceful, though it can occasionally turn faintly grim, and confusion is possible.
Visual
Visuals are present but understated, described in one account as not too pronounced.
Tactile
See also: Psychedelic Intensity Scale, Effects of psychedelics (visual, cognitive, miscellaneous)
Pharmacology
Pharmacodynamics
2C-T-21 acts as a partial agonist at the serotonin 5-HT2A receptor with high affinity (Ki = 27 nM),3 which is believed to underlie its psychedelic effects. It produces the head-twitch response in rodents, a behavioral proxy for psychedelic activity.3 Due to its structural similarity to 2C-T-2 and 2C-T-7, 2C-T-21 is also speculated to possess monoamine oxidase inhibitor (MAOI) properties, though this has not been confirmed.
Pharmacokinetics
Very little data exists regarding the metabolism of 2C-T-21. It has been hypothesized that fluoroacetate, a toxic compound, may be produced as a metabolite.
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.
Full Tolerance
Develops almost immediately after ingestion.
Baseline Reset
Approximately 7 days in the absence of further consumption
Half Tolerance
Approximately 3 days
Cross Tolerance
Serotonergic psychedelics
Harm Potential
Addiction & Dependence
Psychological
Extremely Low2C-T-21 is not generally associated with compulsive use; repeated experiences may lessen a person's interest in taking it again. Its use is typically self-limiting.
Toxicity
Multi-organ (Brain, Heart, Lungs, Gonads)
If the hypothesized fluoroacetate metabolite theory is correct, sub-lethal doses may theoretically cause damage to tissues with high metabolic demands; this remains unconfirmed in human studies and should not be assumed to occur at typical doses.
Seizure Risk
A tonic-clonic seizure was documented in the one fatal case, which involved an unknown but presumably very high dose.citation needed These symptoms are consistent with fluoroacetate poisoning. Seizure risk at typical doses (8-12 mg) is unknown due to limited human data.
History & Culture
Discovery and Synthesis
2C-T-21 was first synthesized by Alexander Shulgin, representing the final compound in the 2C-T series to be completed. Shulgin and colleagues first described the substance in scientific literature in 1991,citation needed with detailed documentation appearing in his book PIHKAL (Phenethylamines I
Legality
International
2C-T-21 is not listed in the current official schedules of the 1961 or 1971 conventions or in the 1988 Convention precursor tables.
By Country
Illegal6
GermanyIllegalNeue-psychoaktive-Stoffe-Gesetz, Anlage, Stoffgruppe 119
Regulated under the Neue-psychoaktive-Stoffe-Gesetz (New Psychoactive Substances Act) since November 26, 2016.19 Production, importation for market placement, administration to others, marketing, and trading are punishable offenses.20 Possession is technically illegal but not subject to criminal penalties.21
NetherlandsIllegal (analog/blanket ban)Opiumwet22
2C-T-21 is covered by the Opiumwet's Lijst IA as a substance derived from 2-phenethylamine. Its 2,5-dimethoxyphenyl ring and 4-(2-fluoroethylthio) substituent fall within the listed phenyl-ring substitutions, including alkoxy and alkylsulfanyl groups and their permitted further halogen-containing substitutions. Since 1 July 2025, Article 2a prohibits importing, exporting, preparing, processing, selling, supplying, transporting, possessing, and manufacturing substances in that chemical group, subject to the statutory exemptions.
NorwayIllegalForskrift om narkotika (narkotikaforskriften), FOR-2013-02-14-19923
Norway's Regulations relating to Narcotics list 2C-T-21 by name in the Narkotikalisten under the chemical designation 2-[4-(2-fluoretylsulfanyl)-2,5-dimetoksy-fenyl]etanamin. The list classifies 2C-T-21 as prohibited under section 5 of the regulation.
SwitzerlandIllegalVerordnung des EDI über die Verzeichnisse der Betäubungsmittel, psychotropen Stoffe, Vorläuferstoffe und Hilfschemikalien (BetmVV-EDI), Verzeichnis E, Ziffer 13024
Regulated as a phenethylamine derivative under Verzeichnis E point 130 of the Betäubungsmittelverzeichnisverordnung. Exemptions exist for legitimate scientific or industrial applications.
Controlled / restricted1
AustriaRestrictedNeue-Psychoaktive-Substanzen-Verordnung (NPSV), § 1 Abs. 1 Z 2 and Abs. 2 and Anlage II Z 2; Neue-Psychoaktive-Substanzen-Gesetz (NPSG), §§ 2-5; Suchtmittelgesetz (SMG), § 2; Suchtgiftverordnung (SV), § 1 and Anhang V; Psychotropenverordnung (PV), § 1 and Anlage 156789101112131415
The NPSV provides generic Anlage II Z 2 coverage for this substituted phenethylamine, and the NPSG § 4 penalty applies only to the specified advantage-seeking production/import/export/transfer/supply conduct with intended human psychoactive use. NPSG § 5 provides confiscation subject to its lawful-purpose and non-psychoactive-use guarantee. The current SV and PV schedules do not expressly name 2C-T-21; current SMG § 27 penalties are therefore not assigned to this substance absent a separate legally operative SMG classification. The NPSV generic class does not override the NPSG § 2 medicines-law and SMG exclusions.
Not scheduled1
United StatesUnscheduled (Analogue Act applies)Not specifically scheduled under the Controlled Substances Act. However, due to structural similarity to 2C-T-7, possession or sale intended for human consumption may be prosecuted under the Federal Analogue Act as a Schedule I equivalent. In 2004, a chemical supplier was federally indicted for distributing 2C-T-21 as a controlled substance analogue,27 subsequently pleading guilty in March 2005.citation needed
References
Source Pages
Citations
- Central nervous system (CNS) activity of two new psychoactive compounds. Journal of Psychoactive Drugs, 23(1), 95–96 (January 1991). https://doi.org/10.1080/02791072.1991.104725831
- Shulgin AT, & Shulgin A. (1991). PiHKAL: A Chemical Love Story. Transform Press. https://erowid.org/library/books_online/pihkal/pihkal049.shtml1
- Adam L. Halberstadt, Dino Luethi, Marius C. Hoener, Daniel Trachsel, Simon D. Brandt, & Matthias E. Liechti. (January 2023). Use of the head-twitch response to investigate the structure-activity relationships of 4-thio-substituted 2,5-dimethoxyphenylalkylamines. Psychopharmacology, 240(1), 115–126. https://doi.org/10.1007/s00213-022-06279-2123
- DEA Announces Arrests and Investigation, July 22 2004 (Operation Web Tryp). (n.d.). https://erowid.org/psychoactives/research_chems/research_chems_info1.shtml1
- https://pubchem.ncbi.nlm.nih.gov/rest/pug/compound/name/2c-t-21/property/IUPACName,MolecularFormula,MolecularWeight,CanonicalSMILES,IsomericSMILES/JSON. pubchem.ncbi.nlm.nih.gov (n.d.). https://pubchem.ncbi.nlm.nih.gov/rest/pug/compound/name/2c-t-21/property/IUPACName,MolecularFormula,MolecularWeight,CanonicalSMILES,IsomericSMILES/JSON1
- https://pubchem.ncbi.nlm.nih.gov/rest/pug/compound/name/2c-t-21/synonyms/JSON. pubchem.ncbi.nlm.nih.gov (n.d.). https://pubchem.ncbi.nlm.nih.gov/rest/pug/compound/name/2c-t-21/synonyms/JSON1
- https://ris.bka.gv.at/GeltendeFassung/Bundesnormen/20007642/NPSV%2c%20Fassung%20vom%2027.08.2026.pdf. ris.bka.gv.at (n.d.). https://ris.bka.gv.at/GeltendeFassung/Bundesnormen/20007642/NPSV%2c%20Fassung%20vom%2027.08.2026.pdf1
- https://ris.bka.gv.at/Dokumente/Bundesnormen/NOR40261441/II_106_2024_Anlage_II.pdf. ris.bka.gv.at (n.d.). https://ris.bka.gv.at/Dokumente/Bundesnormen/NOR40261441/II_106_2024_Anlage_II.pdf1
- https://ris.bka.gv.at/GeltendeFassung/Bundesnormen/20007605/NPSG%2c%20Fassung%20vom%2027.08.2026.pdf. ris.bka.gv.at (n.d.). https://ris.bka.gv.at/GeltendeFassung/Bundesnormen/20007605/NPSG%2c%20Fassung%20vom%2027.08.2026.pdf1
- https://www.ris.bka.gv.at/Dokumente/BgblAuth/BGBLA_2011_I_146/BGBLA_2011_I_146.pdf. ris.bka.gv.at (n.d.). https://www.ris.bka.gv.at/Dokumente/BgblAuth/BGBLA_2011_I_146/BGBLA_2011_I_146.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.
- Step 2 · First-pass review
A first pass manual review and edit of article prose and copy has been performed by subject-matter expert Lyrea. This does not guarantee factual accuracy. An additional human review for each of this article's citations is yet to be performed.
- 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
Times are UTCNewest first
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
Suggest an edit
Spotted a mistake, an outdated claim, or something missing from the 2C-T-21 article? Send the editors a private note. Feedback lands in a moderation queue and is never shown on the site.
Wish to give generalised feedback? You can do so here.