spec sheet10 rows
2C-B-FLY is the tetrahydrobenzodifuran ("FLY") analog of 2C-B, in which the 2- and 5-methoxy groups are locked into fused dihydrofuran rings, conformationally constraining the molecule into an orientation favorable for serotonin 5-HT2A receptor binding. It acts principally as a 5-HT2A receptor agonist, and in vitro profiling shows potent interaction with 5-HT2 receptors together with a predicted risk of vasoconstriction; in mouse head-twitch assays it is roughly equipotent with 2C-B, whereas full aromatization to the benzodifuran ("DragonFLY") markedly increases potency. Metabolism proceeds mainly through CYP2D6-mediated hydroxylation and N-acetylation, with additional monoamine oxidase involvement noted for related FLY compounds. The substance has been linked to serious and fatal intoxications, in part because of confusion with, or contamination by, the far more potent and long-acting Bromo-DragonFLY, whose resistance to hepatic metabolism and prolonged vasoconstrictor action have produced documented deaths. It is detectable in urine alongside other 2C designer drugs by liquid chromatography-mass spectrometry methods.
- Long, warm, visual psychedelic character
- Higher 5-HT2A affinity from the fused-ring structure
- Rigidified benzodifuran scaffold constrains the active 5-HT2A conformation
- Easily confused with the far more dangerous Bromo-DragonFLY
- Very long duration makes redosing risky
Mechanism
2C-B-FLY is 2C-B with its 2- and 5-methoxy groups tied back into two fused dihydrofuran rings, which rigidifies the molecule and increases its affinity and duration at the receptor, the receptor that drives the classic psychedelic state. It also acts at 5-HT2C and other serotonin sites. The ring fusion slows onset and extends the experience compared with 2C-B, and the added rigidity generally raises potency.
receptor fingerprint
receptoragonist
5-HT2C receptoragonist
Safetyrisks and cautions, not medical advice
2C-B-FLY has caused fatalities, and it is easily confused with Bromo-DragonFLY, a related but vastly more potent and vasoconstrictive compound that has caused limb-threatening injuries and deaths; mislabeling makes this class especially hazardous. It should not be combined with MAOIs or other strongly serotonergic drugs because of serotonin toxicity, and its slow, long course makes redosing dangerous. People with heart conditions or a personal or family history of psychosis should avoid it. Not medical advice.
Subjective profileweighing the evidence above
Not one to take casually, and arguably not at all: it has caused fatalities, and it is easily confused with Bromo-DragonFLY, which has cost people limbs and lives. Its own long, slow course makes impatient redosing the second hazard.
Resources
This entry is here for reference.
Research
- 2008first citedLiquid chromatography-atmospheric pressure ionization electrospray mass spectrometry determinat…
- 2019most active year3 papers
- 2023most recentAcute pharmacological profile of 2C-B-Fly-NBOMe in male Wistar rats-pharmacokinetics, effects o…
- 1.Comparison of the behavioral responses induced by phenylalkylamine hallucinogens and their tetrahydrobenzodifuran ("FLY") and benzodifuran ("DragonFLY") analogs.
- 2.Bromo-dragonfly, a psychoactive benzodifuran, is resistant to hepatic metabolism and potently inhibits monoamine oxidase A.
- 3.Pharmacological profile of novel psychoactive benzofurans.
- 4.Phenethylamine-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 screenings.
- 5.Interactions of phenethylamine-derived psychoactive substances of the 2C-series with human monoamine oxidases.
- 6.A fatal poisoning involving Bromo-Dragonfly.
- 7.Liquid chromatography-atmospheric pressure ionization electrospray mass spectrometry determination of "hallucinogenic designer drugs" in urine of consumers.
- 8.Acute pharmacological profile of 2C-B-Fly-NBOMe in male Wistar rats-pharmacokinetics, effects on behaviour and thermoregulation.
- 9.2C or not 2C: phenethylamine designer drug review.
9 listed here; entry last updated August 2026
Reviews
My notesprivate to this device
FAQ
Is 2C-B-FLY the same as Bromo-DragonFLY?
No. They are different compounds; Bromo-DragonFLY is far more potent and dangerous, and confusing the two has led to serious harm.
How does it work?
Mainly through agonism at the 5-HT2A serotonin receptor, with the fused furan rings raising its potency and duration versus 2C-B.
Is it long-lasting?
Yes. It has a slow onset and a long plateau, which is one reason redosing is risky.
Adverse effects
- Easily confused with the far more dangerous Bromo-DragonFLY
- Very long duration makes redosing risky
Notes and cautions
- Documented deaths, partly from mislabeling