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2C-I Facts

Psychedelic; Substituted phenethylamine; Serotonin 2A receptor agonist

Description

2C-I (2,5-dimethoxy-4-iodophenethylamine) is a synthetic psychedelic of the phenethylamine class. It activates serotonin receptors in the brain, producing the visual distortions and perceptual shifts characteristic of classical psychedelics.[1]

Subjective effects include geometric visual patterns, brightened colors, tactile enhancement, mood elevation, and a persistent physical energy.[2] The experience carries a distinct stimulant character — more physically energizing than tryptamine psychedelics, with vivid colors and a social warmth that places it between 2C-B and mescaline.

2C-I does not produce physical dependence,[3] and rapid tolerance limits repeated use;[4] the primary risk is cardiovascular — high blood pressure and vasoconstriction can trigger serious events in predisposed individuals.[5] Combining it with antidepressants or MAOIs dramatically amplifies effects and risks a life-threatening serotonin response.

Dose and durationby route · individual sensitivity varies

Oral(mg)
Threshold< 2 mgLight5 – 10 mgCommon10 – 20 mgStrong20 – 30 mgHeavy30+ mg

Starts in 15 – 45 minLasts 6 – 10 hoursAfter-effects 2 – 8 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
8.5 days
Carries over to
LSD; psilocybin; mescaline; 2C-B; 2C-E; DOI; DMT

Effectslikely at a common dose

Perception
Color enhancement; Color alteration; Environmental patterning; Music enhancement; Tracers; Visual drifting; Brightness alteration; Geometry; Visual breathing; +29 possible, including Visual haze / noise, Spatial disorientation, Vestibular distortion
Body
Stimulation; Pupil dilation; Wakefulness; Body scan awareness; +31 possible, including Muscle tension, Heart rate perception changes, Insomnia
Thinking
Aesthetic enhancement; +35 possible, including Cognitive impairment, Suggestibility enhancement, Memory suppression
Feeling
Emotional enhancement; +8 possible, including Emotional lability, Anxiety, Dysphoria
Self
none likely · 10 possible, including Derealization, Depersonalization, Communication suppression
Time
Time alteration; +3 possible, including Temporal disorientation
Transpersonal
none likely · 1 possible
Awareness
none likely · 5 possible

Who shouldn't take it

Absolute
Cerebrovascular disease; Uncontrolled hypertension; Psychotic disorders; Pregnancy and breastfeeding
Relative
Structural heart disease; Epilepsy; Bipolar disorder

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-i
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]
    ^Halberstadt AL, Geyer MA (2014) Effects of the hallucinogen 2,5-dimethoxy-4-iodophenethylamine (2C-I) and superpotent N-benzyl derivatives on the head twitch response — Neuropharmacology doi:10.1016/j.neuropharm.2013.08.025
  2. [2]
    ^Shulgin A, Shulgin A (1991) PiHKAL: A Chemical Love Story Link
  3. [3]
    ^Gil-Martins E, Barbosa DJ, Borges F, Remiao F, Silva R (2025) Toxicodynamic insights of 2C and NBOMe drugs - Is there abuse potential? — Toxicology Reports doi:10.1016/j.toxrep.2025.101890
  4. [4]
    ^Wallach J, Cao AB, Calkins MM, Heim AJ, Lanham JK, et al. (2023) Identification of 5-HT2A receptor signaling pathways associated with psychedelic potential — Nature Communications doi:10.1038/s41467-023-44016-1
  5. [5]
    ^Drees JC, Stone JA, Wu AH (2009) Morbidity involving the hallucinogenic designer amines MDA and 2C-I — Journal of Forensic Sciences doi:10.1111/j.1556-4029.2009.01199.x
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