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2C-B-FLY Facts

Psychedelic; Substituted phenethylamine; Serotonin 2A receptor agonist

Description

2C-B-FLY is a synthetic psychedelic of the phenethylamine class. It is a structurally locked structural analog of 2C-B — the ring system freezes the molecule into the active shape needed to engage serotonin receptors. That activation disrupts sensory filtering and produces the visual distortions and altered thinking characteristic of classical psychedelics.

Subjective effects include geometric visual patterns, color enhancement, mood elevation, and physical body load. The experience is more physically grounded and longer-lasting than 2C-B — a weighted, immersive quality from a persistent somatic heaviness beneath the visual and cognitive shifts.[1]

2C-B-FLY does not cause physical dependence,[2] and its toxic dose in humans is unknown. The primary danger is cardiovascular — it strongly constricts blood vessels and raises blood pressure[3] — amplified by its potential to inhibit enzymes that break down serotonin, making combinations with serotonergic drugs life-threatening.[4]

Dose and durationby route · individual sensitivity varies

Oral(mg)
Threshold< 2 mgLight5 – 10 mgCommon10 – 18 mgStrong18 – 25 mgHeavy25+ mg

Starts in 30 – 60 minLasts 7 – 12 hoursAfter-effects 6 – 24 hours

Body and dependence

Acute toxicity
Low
Chronic toxicity
Moderate
Physical dependence
None
Psychological dependence
Negligible
Withdrawal
None recorded
Compulsive redosing
Negligible

Tolerance

Builds
Rapid
Fully resets after
7 days
Carries over to
LSD; psilocybin; mescaline; DMT; 2C-B; DOB; DOI; DOC

Effectslikely at a common dose

Perception
Color enhancement; Visual drifting; Color alteration; Music enhancement; Geometry; Visual breathing; +30 possible, including Spatial disorientation, Vestibular distortion, Visual haze / noise
Body
Pupil dilation; Wakefulness; Body high; Body scan awareness; Insomnia; Stimulation; +30 possible, including Heart rate perception changes, Muscle tension, Nausea
Thinking
Pattern recognition enhancement; Novelty enhancement; Aesthetic enhancement; Introspection enhancement; Openness enhancement; +33 possible, including Suggestibility enhancement, Memory suppression, Cognitive impairment
Feeling
Emotional enhancement; Euphoria; +8 possible, including Emotional lability, Anxiety, Dysphoria
Self
none likely · 9 possible, including Derealization, Depersonalization
Time
Time alteration; +3 possible, including Temporal disorientation
Transpersonal
none likely · 1 possible
Awareness
none likely · 5 possible

Who shouldn't take it

Absolute
Uncontrolled hypertension; Peripheral vascular disease; Psychotic disorders; Pregnancy and breastfeeding; Concurrent MAOI use; Concurrent tramadol use
Relative
Epilepsy; Bipolar disorder; Hepatic impairment

Combinations61 recorded

Lethal (1)
MAOIs
Dangerous (18)
MDMA, MDA; NRIs; Buspirone; Dopamine agonists; GHB, Baclofen; GHB, GBL; Ibogaine; Ketamine, DXM, PCP; Lithium; Local anesthetics; MDMA, Amphetamines; NDRIs (Wellbutrin); Psychedelics; Salvia, Ibogaine; SNRIs; SSRIs; Stimulants; Synthetic cannabinoids
Caution (37)
See full page: psychedex.org/substances/2c-b-fly
Not graded (5)
Not listed never means safe.

Seek help immediately if

Most difficulty is psychological (intense fear, panic, confusion) and passes with calm support — the signs below mean seek emergency help:

  • Very high body temperature; hot, dry skin
  • Seizures
  • Chest pain; fast or irregular heartbeat
  • Severe muscle rigidity, tremor, or twitching (possible serotonin syndrome)
  • Cold, pale, or blue fingers/toes — severe vasoconstriction (notably NBOMe / DOx)
  • Persistent vomiting; unconsciousness; uncontrollable agitation or risk of self-harm

What to do

  1. Stay calm and reassure — remind them they took a drug and the effect will pass
  2. Move to a calm, quiet, safe space with low light; reduce noise and sensory input
  3. Keep them from harm — they may act on fear or confusion; stay with them, don't leave them alone
  4. Talk them down gently; don't grab or restrain unless they're in danger
  5. For the medical signs above (overheating, seizure, chest pain, vasoconstriction, unresponsive) call emergency services
  6. If overheating, cool the body; be ready to give rescue breaths / CPR

The experience is time-limited and usually resolves with calm reassurance in a safe setting — psychological first aid, not medication. Serious physical harm is uncommon for classic psychedelics (LSD, psilocybin) but real for some potent phenethylamines (NBOMe, DOx), where hyperthermia, seizures, and vasoconstriction warrant emergency care.

988 Suicide & Crisis LifelineFireside Project: 62-FIRESIDE

Version r1 · Not medical advice

References

  1. [1]
    ^Mallaroni P, Mason NL, Reckweg JT, Paci R, Ritscher S, Toennes SW, Theunissen EL, Kuypers KPC, Ramaekers JG (2023) Assessment of the Acute Effects of 2C-B vs. Psilocybin on Subjective Experience, Mood, and Cognition — Clinical Pharmacology and Therapeutics doi:10.1002/cpt.2958
  2. [2]
    ^Nichols DE (2004) Hallucinogens — Pharmacology & Therapeutics PMID:14761703
  3. [3]
    ^Rickli A, Kopf S, Hoener MC, Liechti ME (2015) Pharmacological profile of novel psychoactive benzofurans — British Journal of Pharmacology doi:10.1111/bph.13128
  4. [4]
    ^Wagmann L, Brandt SD, Stratford A, Maurer HH, Meyer MR (2019) Interactions of phenethylamine-derived psychoactive substances of the 2C-series with human monoamine oxidases — Drug Testing and Analysis doi:10.1002/dta.2494
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