What are the risks of 2C-T-21?

Critical Safety Warning 2C-T-21 shares all the fundamental toxicity concerns of 2C-T-2 and 2C-T-7: MAO interaction and serotonin toxicity risk — elevated risk of serotonin syndrome, especially in combination with serotonergic substances Cardiovascular risk — documented for the thio-phenethylamine cl

How long does 2C-T-21 last?

The total duration of 2C-T-21 via oral is 10 hours to 12 hours. Onset typically occurs within 1.5 hours to 2 hours. Peak effects last 3 hours to 4 hours.

2C-T-21 — SubstanceWiki

2C-T-21 (2,5-dimethoxy-4-(2-fluoroethylthio)phenethylamine) is a psychedelic thiophenethylamine and lesser-known member of the 2C-T family, first synthesized by Alexander Shulgin and documented in PiHKAL (1991). It is the 4-(2-fluoroethylthio) analog — a thio-phenethylamine with a fluorine-substituted ethyl chain on the sulfur, distinguishing it from the simpler 2C-T-2 (ethylthio) and 2C-T-7 (propylthio) analogs.

2C-T-21 is among the least studied and most obscure members of the 2C-T family. The fluoroethyl modification adds pharmacological complexity relative to simpler thio-phenethylamines: fluorine substitution can alter metabolic pathways and receptor interactions in ways that are difficult to predict from parent compound data alone. Given the documented toxicity of 2C-T-2 and 2C-T-7, and 2C-T-21's structural similarity to both, the compound carries the same fundamental safety concerns about MAO interaction and serotonin toxicity.

The psychedelic character of 2C-T-21, where documented, appears broadly similar to other members of the 2C-T family — moderate duration visual effects, sensory enhancement, and emotionally variable headspace. However, the virtually nonexistent safety data and the family's documented toxicity history make 2C-T-21 one of the highest-caution compounds in the phenethylamine space.

How It Feels

The onset is slow and methodical. An hour or more may pass before the first effects become clearly discernible -- a gradual brightening of the visual field and a subtle shift in cognitive texture that is difficult to pinpoint but impossible to ignore. The body warms gently, and there may be mild gastrointestinal stirring typical of the thio-substituted 2C compounds, though it tends to be less pronounced than with 2C-T-2 or 2C-T-7. A quiet, steady energy begins to accumulate, building without urgency.

By the two-hour mark, the experience has established itself as a moderate psychedelic state with a distinctly contemplative character. Visual effects unfold in flowing, organic patterns that overlay surfaces with soft, warm geometry. Colors are enriched without being garish -- there is a natural, almost autumnal quality to the palette, with deep golds, burnt oranges, and rich greens appearing particularly vivid. Surfaces breathe slowly, and the world acquires a slightly dreamlike quality where everything seems simultaneously more real and more symbolic. The visual effects, while clearly present, never overwhelm -- they enhance the environment rather than replacing it.

The headspace is introspective and measured. Thoughts move at a comfortable pace, often turning toward reflective territory without the aggressive analytical forcing that characterizes 2C-E. There is a philosophical quality to the contemplation -- a tendency to consider broader themes of meaning, connection, and purpose rather than fixating on personal psychological material. Emotionally, the state is warm and stable, with a quiet contentment that anchors the experience against anxiety or difficult turns. Music is gently enhanced, and solitude feels as comfortable as company. The body load is minimal, limited to occasional mild nausea and a light stimulant awareness.

The duration is the distinguishing logistical feature of 2C-T-21. Effects sustain for eight to twelve hours, with a long, gradual plateau that neither intensifies dramatically nor fades prematurely. The descent is correspondingly slow and smooth, with effects tapering off gently over the final hours. The aftermath is clean and may include a mild afterglow of reflective clarity. The long duration demands planning but rewards it with a sustained, stable journey that allows extended contemplation without the exhausting intensity spikes of more volatile compounds.

Subjective Effects

The effects listed below are based on the Subjective Effect Index (SEI), an open research literature based on anecdotal reports and personal analyses. They should be viewed with a healthy degree of skepticism. These effects will not necessarily occur in a predictable or reliable manner, although higher doses are more liable to induce the full spectrum of effects.

Physical Effects

Physical(13)

Body load— A diffuse, heavy physical discomfort involving tension, pressure, and malaise in the torso and limbs...
Dehydration— A state of insufficient bodily hydration manifesting as persistent thirst, dry mouth, and physical d...
Dizziness— A sensation of spinning, swaying, or lightheadedness that impairs balance and spatial orientation, o...
Excessive yawning— Involuntary, repeated yawning that occurs far more frequently than normal and often without the usua...
Frequent urination— Increased urinary frequency beyond normal patterns, caused by diuretic effects or bladder irritation...
Increased heart rate— A noticeable acceleration of heartbeat that can range from a subtle awareness of one's pulse to a fo...
Nausea— An uncomfortable sensation of queasiness and stomach discomfort that may or may not lead to vomiting...
Physical euphoria— An intensely pleasurable bodily sensation that can manifest as waves of warmth, tingling electricity...
Pupil dilation— A visible enlargement of the pupil diameter (mydriasis) that can range from subtle widening to drama...
Sedation— A state of deep physical and mental calming that manifests as a progressive desire to remain still, ...
Stimulation— A state of heightened physical and mental energy characterized by increased wakefulness, elevated mo...
Teeth grinding— An involuntary clenching and rhythmic grinding of the jaw muscles, known clinically as bruxism, that...
Watery eyes— Excessive tear production causing overflow tearing and blurred vision, commonly occurring during opi...

Tactile(1)

Tactile enhancement— The sense of touch becomes dramatically heightened, making physical contact feel intensely pleasurab...

Cognitive & Perceptual Effects

Visual(12)

After images— A visual phenomenon in which a faint, ghostly imprint of a previously viewed image persists in the v...
Colour enhancement— An intensification of the brightness, vividness, and saturation of colors in the external environmen...
Colour shifting— The visual experience of colors on objects and surfaces cycling through continuous, fluid transforma...
Drifting— The visual experience of perceiving stationary objects, textures, and surfaces as appearing to flow,...
Geometry— The experience of perceiving complex, ever-shifting geometric patterns superimposed over the visual ...
Internal hallucination— Vivid, detailed visual experiences perceived within an imagined mental landscape that can only be se...

Detection Methods

Urine Detection

2C-T-21 is not specifically targeted by standard immunoassay-based urine drug panels. However, because 2C-x phenethylamines share structural features with amphetamines, they may trigger false positives on amphetamine immunoassays in some cases. The likelihood of cross-reactivity depends on the specific immunoassay manufacturer and the antibody selectivity used. Urine detection windows for 2C-T-21 are estimated at 24 to 72 hours following ingestion when analyzed by LC-MS/MS methods, though limited pharmacokinetic data exists for many 2C-x compounds.

Blood and Serum Detection

Blood detection windows for 2C-T-21 are approximately 6 to 24 hours after oral administration. Peak plasma concentrations typically occur 1 to 3 hours post-ingestion. The relatively short half-lives of most 2C-x phenethylamines mean that blood testing must be performed promptly to capture detectable concentrations. LC-MS/MS is the only reliable method for quantitative blood analysis.

Standard Drug Panel Inclusion

2C-T-21 is NOT specifically included on standard 5-panel, 10-panel, or 12-panel drug screens. The primary concern for individuals undergoing routine screening is the potential for amphetamine cross-reactivity on immunoassay-based panels. If a presumptive positive for amphetamines occurs, confirmatory testing by GC-MS or LC-MS/MS would not confirm amphetamine and the result would be reported as negative unless the laboratory specifically tests for 2C-x compounds. Most routine laboratories do not include 2C-x phenethylamines in their confirmatory panels.

Confirmatory Methods

Definitive identification of 2C-T-21 requires LC-MS/MS or GC-MS with appropriate reference standards. Some forensic toxicology laboratories include 2C-x phenethylamines in their extended novel psychoactive substance panels. Immunoassay cross-reactivity alone is insufficient for confirmation and would be resolved by standard confirmatory procedures. Quantitative analysis typically requires specific method development as these compounds are not part of routine clinical chemistry workflows.

Reagent Testing (Harm Reduction)

For harm reduction identification, the Marquis reagent is a primary screening tool for 2C-T-21. The Marquis reagent produces a variable brown to green reaction with 2C-T-21. The Mecke reagent may provide additional color reactions that help differentiate between specific 2C-x variants. The Ehrlich reagent shows no reaction with 2C-x phenethylamines, which can help distinguish them from tryptamines and lysergamides. The Mandelin reagent may produce green to brown reactions depending on the specific compound. Using multiple reagents in combination provides the most reliable field identification, though reagent testing cannot determine purity or dosage.

Interactions

Substance	Status	Note
2-Aminoindane	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
2-FA	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
2-FEA	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
2-FMA	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
2,5-DMA	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
2C-H	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
3-FA	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
3-FEA	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
3-FMA	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
3-FPM	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
3-MMC	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
3,4-CTMP	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
4-FA	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
4-FMA	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
4-MMC	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
4F-EPH	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
4F-MPH	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
5-APB	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
5F-AKB48	Caution	Cannabis can unpredictably intensify psychedelic effects and increase anxiety
5F-PB-22	Caution	Cannabis can unpredictably intensify psychedelic effects and increase anxiety
6-APDB	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
8-Chlorotheophylline	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
A-PHP	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
A-PVP	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
AB-FUBINACA	Caution	Cannabis can unpredictably intensify psychedelic effects and increase anxiety
Adrafinil	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Amphetamine	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Anandamide	Caution	Cannabis can unpredictably intensify psychedelic effects and increase anxiety
APICA	Caution	Cannabis can unpredictably intensify psychedelic effects and increase anxiety
Armodafinil	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Atropa belladonna	Caution	Unpredictable compounding of hallucinogenic effects with anticholinergic delirium
Benzydamine	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Bromantane	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Butylone	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Caffeine	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Cannabidiol	Caution	Cannabis can unpredictably intensify psychedelic effects and increase anxiety
Cannabis	Caution	Cannabis can unpredictably intensify psychedelic effects and increase anxiety
Cocaine	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Cyclazodone	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Datura	Caution	Unpredictable compounding of hallucinogenic effects with anticholinergic delirium
Desoxypipradrol	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Dextroamphetamine	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Dichloropane	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Diphenhydramine	Caution	Unpredictable compounding of hallucinogenic effects with anticholinergic delirium
Ephedrine	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Ephylone	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
ETH-CAT	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Ethylone	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Ethylphenidate	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Fenethylline	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Harmala alkaloid	Caution	MAOIs dramatically potentiate psychedelics; drastically reduce dose and exercise extreme caution
Hexedrone	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Isopropylphenidate	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
JWH-018	Caution	Cannabis can unpredictably intensify psychedelic effects and increase anxiety
JWH-073	Caution	Cannabis can unpredictably intensify psychedelic effects and increase anxiety
Kratom	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Lisdexamfetamine	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
MAOI	Caution	MAOIs dramatically potentiate psychedelics; drastically reduce dose and exercise extreme caution
MCPP	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
MDA	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
MDMA	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
MDPV	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Mephedrone	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Methamphetamine	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Methcathinone	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Methiopropamine	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Methylnaphthidate	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Methylone	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Methylphenidate	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Mexedrone	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Mirtazapine	Caution	Unpredictable compounding of hallucinogenic effects with anticholinergic delirium
Modafinil	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Myristicin	Caution	Unpredictable compounding of hallucinogenic effects with anticholinergic delirium
N-Ethylhexedrone	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
N-Methylbisfluoromodafinil	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
NEP	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Nicotine	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
NM-2-AI	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Oxiracetam	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Peganum harmala	Caution	MAOIs dramatically potentiate psychedelics; drastically reduce dose and exercise extreme caution
Pentedrone	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Phenylpiracetam	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
Rhodiola Rosea	Caution	Increases anxiety, cardiovascular stress, and psychological intensity
1,3-Butanediol	Low Risk & Synergy	Cross-tolerance exists; effects compound
1B-LSD	Low Risk & Synergy	Cross-tolerance exists; effects compound
1cP-AL-LAD	Low Risk & Synergy	Cross-tolerance exists; effects compound
1cP-LSD	Low Risk & Synergy	Cross-tolerance exists; effects compound
1cP-MiPLA	Low Risk & Synergy	Cross-tolerance exists; effects compound
1P-ETH-LAD	Low Risk & Synergy	Cross-tolerance exists; effects compound
1P-LSD	Low Risk & Synergy	Cross-tolerance exists; effects compound
1V-LSD	Low Risk & Synergy	Cross-tolerance exists; effects compound
2-Fluorodeschloroketamine	Low Risk & Synergy	Produces unique synergistic effects; often combined
25B-NBOH	Low Risk & Synergy	Cross-tolerance exists; effects compound
25B-NBOMe	Low Risk & Synergy	Cross-tolerance exists; effects compound
25C-NBOH	Low Risk & Synergy	Cross-tolerance exists; effects compound
25C-NBOMe	Low Risk & Synergy	Cross-tolerance exists; effects compound
25D-NBOMe	Low Risk & Synergy	Cross-tolerance exists; effects compound
25E-NBOH	Low Risk & Synergy	Cross-tolerance exists; effects compound
25I-NBOH	Low Risk & Synergy	Cross-tolerance exists; effects compound
25I-NBOMe	Low Risk & Synergy	Cross-tolerance exists; effects compound
25N-NBOMe	Low Risk & Synergy	Cross-tolerance exists; effects compound
2C-B	Low Risk & Synergy	Cross-tolerance exists; effects compound
2C-B-FLY	Low Risk & Synergy	Cross-tolerance exists; effects compound
2C-C	Low Risk & Synergy	Cross-tolerance exists; effects compound
2C-D	Low Risk & Synergy	Cross-tolerance exists; effects compound
2C-E	Low Risk & Synergy	Cross-tolerance exists; effects compound
2C-I	Low Risk & Synergy	Cross-tolerance exists; effects compound
2C-P	Low Risk & Synergy	Cross-tolerance exists; effects compound
2C-T	Low Risk & Synergy	Cross-tolerance exists; effects compound
2C-T-2	Low Risk & Synergy	Cross-tolerance exists; effects compound
2C-T-7	Low Risk & Synergy	Cross-tolerance exists; effects compound
3-Cl-PCP	Low Risk & Synergy	Produces unique synergistic effects; often combined
3-HO-PCE	Low Risk & Synergy	Produces unique synergistic effects; often combined
3-HO-PCP	Low Risk & Synergy	Produces unique synergistic effects; often combined
3-MeO-PCE	Low Risk & Synergy	Produces unique synergistic effects; often combined
3-MeO-PCMo	Low Risk & Synergy	Produces unique synergistic effects; often combined
3-MeO-PCP	Low Risk & Synergy	Produces unique synergistic effects; often combined
3C-E	Low Risk & Synergy	Cross-tolerance exists; effects compound
3C-P	Low Risk & Synergy	Cross-tolerance exists; effects compound
4-AcO-DET	Low Risk & Synergy	Cross-tolerance exists; effects compound
4-AcO-DiPT	Low Risk & Synergy	Cross-tolerance exists; effects compound
4-AcO-DMT	Low Risk & Synergy	Cross-tolerance exists; effects compound
4-AcO-MET	Low Risk & Synergy	Cross-tolerance exists; effects compound
4-AcO-MiPT	Low Risk & Synergy	Cross-tolerance exists; effects compound
4-HO-DET	Low Risk & Synergy	Cross-tolerance exists; effects compound
4-HO-DiPT	Low Risk & Synergy	Cross-tolerance exists; effects compound
4-HO-DPT	Low Risk & Synergy	Cross-tolerance exists; effects compound
4-HO-EPT	Low Risk & Synergy	Cross-tolerance exists; effects compound
4-HO-MET	Low Risk & Synergy	Cross-tolerance exists; effects compound
4-HO-MiPT	Low Risk & Synergy	Cross-tolerance exists; effects compound
4-HO-MPT	Low Risk & Synergy	Cross-tolerance exists; effects compound
4-MeO-PCP	Low Risk & Synergy	Produces unique synergistic effects; often combined
5-MeO-DALT	Low Risk & Synergy	Cross-tolerance exists; effects compound
5-MeO-DiBF	Low Risk & Synergy	Cross-tolerance exists; effects compound
5-MeO-DiPT	Low Risk & Synergy	Cross-tolerance exists; effects compound
5-MeO-DMT	Low Risk & Synergy	Cross-tolerance exists; effects compound
5-MeO-MiPT	Low Risk & Synergy	Cross-tolerance exists; effects compound
6-APB	Low Risk & Synergy	Cross-tolerance exists; effects compound
AL-LAD	Low Risk & Synergy	Cross-tolerance exists; effects compound
ALD-52	Low Risk & Synergy	Cross-tolerance exists; effects compound
Allylescaline	Low Risk & Synergy	Cross-tolerance exists; effects compound
Ayahuasca	Low Risk & Synergy	Cross-tolerance exists; effects compound
Bromo-DragonFLY	Low Risk & Synergy	Cross-tolerance exists; effects compound
Bufotenin	Low Risk & Synergy	Cross-tolerance exists; effects compound
Deschloroketamine	Low Risk & Synergy	Produces unique synergistic effects; often combined
DET	Low Risk & Synergy	Cross-tolerance exists; effects compound
Dextromethorphan	Low Risk & Synergy	Produces unique synergistic effects; often combined
Diphenidine	Low Risk & Synergy	Produces unique synergistic effects; often combined
DiPT	Low Risk & Synergy	Cross-tolerance exists; effects compound
DMT	Low Risk & Synergy	Cross-tolerance exists; effects compound
DOB	Low Risk & Synergy	Cross-tolerance exists; effects compound
DOC	Low Risk & Synergy	Cross-tolerance exists; effects compound
DOI	Low Risk & Synergy	Cross-tolerance exists; effects compound
DOM	Low Risk & Synergy	Cross-tolerance exists; effects compound
DPT	Low Risk & Synergy	Cross-tolerance exists; effects compound
Efavirenz	Low Risk & Synergy	Cross-tolerance exists; effects compound
Ephenidine	Low Risk & Synergy	Produces unique synergistic effects; often combined
EPT	Low Risk & Synergy	Cross-tolerance exists; effects compound
Escaline	Low Risk & Synergy	Cross-tolerance exists; effects compound
ETH-LAD	Low Risk & Synergy	Cross-tolerance exists; effects compound
HXE	Low Risk & Synergy	Produces unique synergistic effects; often combined
Ibogaine	Low Risk & Synergy	Cross-tolerance exists; effects compound
Inhalants	Low Risk & Synergy	Produces unique synergistic effects; often combined
Ketamine	Low Risk & Synergy	Produces unique synergistic effects; often combined
LAE-32	Low Risk & Synergy	Cross-tolerance exists; effects compound
LSA	Low Risk & Synergy	Cross-tolerance exists; effects compound
LSD	Low Risk & Synergy	Cross-tolerance exists; effects compound
LSM-775	Low Risk & Synergy	Cross-tolerance exists; effects compound
LSZ	Low Risk & Synergy	Cross-tolerance exists; effects compound
Memantine	Low Risk & Synergy	Produces unique synergistic effects; often combined
Mescaline	Low Risk & Synergy	Cross-tolerance exists; effects compound
MET	Low Risk & Synergy	Cross-tolerance exists; effects compound
Methallylescaline	Low Risk & Synergy	Cross-tolerance exists; effects compound
Methoxetamine	Low Risk & Synergy	Produces unique synergistic effects; often combined
Methoxphenidine	Low Risk & Synergy	Produces unique synergistic effects; often combined
MiPLA	Low Risk & Synergy	Cross-tolerance exists; effects compound
MiPT	Low Risk & Synergy	Cross-tolerance exists; effects compound
MPT	Low Risk & Synergy	Cross-tolerance exists; effects compound
MXiPr	Low Risk & Synergy	Produces unique synergistic effects; often combined
Nitrous	Low Risk & Synergy	Produces unique synergistic effects; often combined
O-PCE	Low Risk & Synergy	Produces unique synergistic effects; often combined
PARGY-LAD	Low Risk & Synergy	Cross-tolerance exists; effects compound
PCE	Low Risk & Synergy	Produces unique synergistic effects; often combined
PCP	Low Risk & Synergy	Produces unique synergistic effects; often combined
PRO-LAD	Low Risk & Synergy	Cross-tolerance exists; effects compound
Psilocybin Mushrooms	Low Risk & Synergy	Cross-tolerance exists; effects compound
Codeine	Low Risk & No Synergy	No significant pharmacological interaction; opioids may slightly dull the psychedelic experience
Fentanyl	Low Risk & No Synergy	No significant pharmacological interaction; opioids may slightly dull the psychedelic experience
Heroin	Low Risk & No Synergy	No significant pharmacological interaction; opioids may slightly dull the psychedelic experience
Morphine	Low Risk & No Synergy	No significant pharmacological interaction; opioids may slightly dull the psychedelic experience
Oxycodone	Low Risk & No Synergy	No significant pharmacological interaction; opioids may slightly dull the psychedelic experience
Alcohol	Low Risk & Decrease	Depressants dull psychedelic effects; benzodiazepines are commonly used as trip-killers
Alprazolam	Low Risk & Decrease	Depressants dull psychedelic effects; benzodiazepines are commonly used as trip-killers
Clonazepam	Low Risk & Decrease	Depressants dull psychedelic effects; benzodiazepines are commonly used as trip-killers
Diazepam	Low Risk & Decrease	Depressants dull psychedelic effects; benzodiazepines are commonly used as trip-killers
GHB	Low Risk & Decrease	Depressants dull psychedelic effects; benzodiazepines are commonly used as trip-killers
Lorazepam	Low Risk & Decrease	Depressants dull psychedelic effects; benzodiazepines are commonly used as trip-killers

Showing 197 key interactions out of 240 total.

Toxicity & Safety

Critical Safety Warning

2C-T-21 shares all the fundamental toxicity concerns of 2C-T-2 and 2C-T-7:

MAO interaction and serotonin toxicity risk — elevated risk of serotonin syndrome, especially in combination with serotonergic substances
Cardiovascular risk — documented for the thio-phenethylamine class generally
Individual variability — same person-to-person unpredictability as other 2C-T compounds

Additional Fluorine Concern

The theoretical fluoroacetate metabolite pathway — however unlikely to be significant at typical doses — represents an additional unknown that does not exist for other 2C compounds. The metabolic fate of the fluoroethyl group under the conditions of actual human metabolism is not established.

No Safety Database

2C-T-21 has no meaningful body of human safety data. Unlike 2C-T-2 and 2C-T-7, which accumulated at least some documented adverse event reports, 2C-T-21 is so rarely used that even adverse events might go unrecognized or uncorrelated.

Absolute Contraindications

MAOIs of any kind
Other serotonergic substances
Stimulants
Cardiovascular conditions

Addiction Potential

not habit-forming

Overdose Information

lethal doses may cause damage to tissue with high energy needs (e.g. the brain, gonads, heart, lungs, and fetus). This may account for the experience of a couple who became "convinced that it is toxic" in Stolaroff's book. This may make it dangerous to combine it with other MAOIs, stimulants and certain substances which releases neurotransmitters such as serotonin or dopamine. These substances include but are not limited to:

Austria: 2C-T-21 is illegal to possess, produce and sell under the NPSG (Neue-Psychoaktive-Substanzen-Gesetz Österreich).
Canada: As of October 31st, 2016; 2C-T-21 is a controlled substance (Schedule III) in Canada.
Germany: 2C-T-21 is controlled under the NpSG (New Psychoactive Substances Act) as of November 26, 2016. Production and import with the aim to place it on the market, administration to another person, placing it on the market and trading is punishable. Possession is illegal but not punishable. The legislator considers it possible that orders of 2C-T-21 are punishable as an incitement to place it on the market.
Switzerland: 2C-T-21 can be considered a controlled substance as a defined derivative of Phenethylamine under Verzeichnis E point 130. It is legal when used for scientific or industrial use.
United Kingdom: 2C-T-21 is a Class A drug in the United Kingdom as a result of the phenethylamine catch-all clause.
United States: 2C-T-21 is technically not scheduled in the United States, but could be considered an analogue of 2C-T or 2C-T-7 and may therefore be considered a Schedule I drug under the Federal Analogue Act.
Responsible use
Volumetric dosing
Research chemical
MAOI
2C-x
2C-T-7
2C-E
2C-T-21 (Wikipedia)
2C-T-21 (Erowid Vault)
2C-T-21 (PiHKAL / Isomer Design)

Full	almost immediately after ingestion
Half	3 days
Zero	7 days

2C-T-21

Quick Dosage

Dosage

oral

Duration

oral

How It Feels

Subjective Effects

Physical Effects

Physical(13)

Tactile(1)

Cognitive & Perceptual Effects

Visual(12)

Pharmacology

Mechanism of Action

Fluorine Modification Effects

MAO Interaction

Data Scarcity

Detection Methods

Urine Detection

Blood and Serum Detection

Standard Drug Panel Inclusion

Confirmatory Methods

Reagent Testing (Harm Reduction)

Interactions

History

Development and PiHKAL

Obscurity

Harm Reduction

Recommendation Against Use

If Use Proceeds

Toxicity & Safety

Critical Safety Warning

Additional Fluorine Concern

No Safety Database

Absolute Contraindications

Addiction Potential

Overdose Information

Tolerance

Cross-tolerances

Legal Status

Experience Reports (2)

Tips (3)

See Also

References (4)

Frequently Asked Questions

Cognitive(12)

Transpersonal(2)