spec sheet10 rows
2C-T-21 is an obscure sulfur-containing member of the 2C-T subfamily, carrying a 2-fluoroethylthio group at the 4 position of the 2,5-dimethoxyphenethylamine scaffold. As a 4-thio-substituted phenethylamine it is presumed to act as a 5-HT2A receptor agonist, the shared mechanism of the 2C-x series; structure-activity work on related compounds indicates that fluorination of the 4-position alkylthio chain is detrimental to activity at the 5-HT2A receptor, so the fluorinated substituent may reduce potency relative to non-fluorinated homologs such as 2C-T-2. In vitro studies of the 2C-series report interactions with human monoamine oxidases. It remains lightly characterized, and its potency and safety margin in humans are not well defined.
- Presumed classic 2C-T psychedelic character
- Long-acting sulfur-substituted profile
- Fluorinated 4-alkylthio group tempers 5-HT2A potency
- Unknown potency raises the risk of overshooting
- Anxiety, nausea, raised heart rate and blood pressure
Mechanism
2C-T-21 is a 2,5-dimethoxyphenethylamine with a thioether (sulfur-linked 2-fluoroethyl) group at the 4 position, placing it in the same 2C-T subfamily as 2C-T-2 and 2C-T-7. By analogy to those compounds it is presumed to act as an at the receptor, with likely secondary serotonin (5-HT2C) activity. Like other 2C-T thioethers it may interact with monoamine oxidase, so combinations are treated as high risk. Human pharmacokinetic data are essentially absent, so specific affinities are best treated conservatively.
receptor fingerprint
receptoragonist (presumed)
5-HT2C receptoragonist (presumed)
Safetyrisks and cautions, not medical advice
As a barely-characterized 2C-T thioether, 2C-T-21 has no established safe range, and the broader 2C-T class includes compounds with real toxicity. General cautions apply: it can raise heart rate and blood pressure, provoke intense anxiety, and it is dangerous to combine with MAOIs or other strongly serotonergic drugs because of serotonin toxicity. People with heart conditions or a personal or family history of psychosis should avoid it. Not medical advice.
Subjective profileweighing the evidence above
Strictly experimental, and not in an interesting way. Four papers, no established dose, and a fluorinated tail that shifted the potency in a direction nobody has pinned down; the realistic outcome is overshooting a very long trip on a compound with no human safety data.
Resources
This entry is here for reference.
Research
- 2012first citedFluorine in psychedelic phenethylamines.
- 2023most recentUse of the head-twitch response to investigate the structure-activity relationships of 4-thio-s…
- 1.Interactions of phenethylamine-derived psychoactive substances of the 2C-series with human monoamine oxidases.
- 2.Use of the head-twitch response to investigate the structure-activity relationships of 4-thio-substituted 2,5-dimethoxyphenylalkylamines.
- 3.Fluorine in psychedelic phenethylamines.
3 listed here; entry last updated August 2026
Reviews
My notesprivate to this device
FAQ
Is 2C-T-21 well studied?
No. It is an obscure research phenethylamine with little published human data, so its effects and safe range are not established.
How does it work?
By analogy to the 2C-T family it is presumed to act mainly through 5-HT2A serotonin receptor agonism.
Is it safe to combine with other drugs?
MAOIs and other strongly serotonergic drugs are dangerous with 2C-T compounds because of serotonin toxicity, and should be avoided.
Limitations of the evidence
- Almost no human safety data
Adverse effects
- Unknown potency raises the risk of overshooting
- Anxiety, nausea, raised heart rate and blood pressure