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2C-B Facts

Psychedelic; Entactogen; Substituted phenethylamine; Serotonin 2A receptor agonist

Description

2C-B (2,5-dimethoxy-4-bromophenethylamine) — Nexus, Bromo, Venus — is a synthetic psychedelic of the phenethylamine class. It activates serotonin receptors in the brain,[1] producing the visual distortion and sensory intensification characteristic of psychedelics, paired with warmth and sociability.

Subjective effects include color enhancement, geometric visual patterns, tactile intensification, heightened sociability, and sensory amplification.[2][3] The experience occupies a boundary between psychedelic perception and entactogenic warmth — vivid and pleasurable at lower doses, shifting steeply toward full psychedelic territory with small dose increases.

2C-B does not produce physical dependence, and no fatality has been attributed to it in published literature.[4] The dominant risk is its steep dose-response curve — small dose increases can escalate a manageable experience into overwhelming psychedelic intensity.[5]

Dose and durationby route · individual sensitivity varies

Oral(mg)
Threshold< 5 mgLight5 – 15 mgCommon15 – 25 mgStrong25 – 40 mgHeavy40+ mg

Starts in 20 – 45 minLasts 4 – 7 hoursAfter-effects 2 – 6 hours

Body and dependence

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

Tolerance

Builds
Rapid
Fully resets after
14 days
Carries over to
LSD; psilocybin; mescaline; DMT; 2C-E; 2C-I; DOB

Effectslikely at a common dose

Perception
Music enhancement; Visual drifting; Color alteration; Symmetrical texture repetition; Color enhancement; Touch enhancement; Environmental patterning; Geometry; Visual breathing; +27 possible, including Visual haze / noise, Spatial disorientation, Vestibular distortion
Body
Stimulation; Spontaneous body sensations; Pupil dilation; Body high; Body scan awareness; Tactile euphoria; +34 possible, including Nausea, Temperature dysregulation, Excessive sweating
Thinking
Novelty enhancement; Aesthetic enhancement; Openness enhancement; +34 possible, including Memory suppression, Cognitive impairment, Decision impairment
Feeling
Emotional enhancement; Euphoria; +8 possible, including Emotional lability, Anxiety, Dysphoria
Self
none likely · 9 possible, including Derealization, Depersonalization
Time
none likely · 5 possible, including Temporal disorientation
Transpersonal
none likely · 1 possible
Awareness
none likely · 4 possible

Who shouldn't take it

Absolute
Uncontrolled hypertension; Psychotic disorders; Bipolar disorder; Pregnancy and breastfeeding; Concurrent MAOI use
Relative
Epilepsy; Concurrent lithium use

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
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.a1 · Not medical advice

References

  1. [1]
    ^Papaseit E, Farre M, Perez-Mana C, Torrens M, Ventura M, Pujadas M, de la Torre R, Gonzalez D (2018) Acute Pharmacological Effects of 2C-B in Humans: An Observational Study — Frontiers in Pharmacology doi:10.3389/fphar.2018.00206
  2. [2]
    ^Caudevilla-Galligo F, Riba J, Ventura M, Gonzalez D, Farre M, Barbanoj MJ, Bouso JC (2012) 4-Bromo-2,5-dimethoxyphenethylamine (2C-B): presence in the recreational drug market in Spain, pattern of use and subjective effects — Journal of Psychopharmacology doi:10.1177/0269881111431752
  3. [3]
    ^Gonzalez D, Torrens M, Farre M (2015) Acute Effects of the Novel Psychoactive Drug 2C-B on Emotions — BioMed Research International doi:10.1155/2015/643878
  4. [4]
    ^Dean BV, Stellpflug SJ, Burnett A, Engebretsen KM (2013) 2C or Not 2C: Phenethylamine Designer Drug Review — Journal of Medical Toxicology doi:10.1007/s13181-013-0295-x
  5. [5]
    ^Shulgin A, Shulgin A (1991) PiHKAL: A Chemical Love Story — Entry #20: 2C-B Link
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