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    Disclaimer
    πŸ§ͺ This is a research chemical with limited data on its long-term health effects, toxicity profile, and safe dosage ranges.

    2C-I Well-documented
    Well-documented
    Multiple authoritative sources agree on dosing and effects.
    • 5 corroborating sources
    • 1 ROA with full dose ladder
    • duration data present
    • 18 combo interactions documented
    • PubChem toxicity data
    • classified Research-chemical

    Aliases: 2ci

    Summary TripSit PsychonautWiki

    2,5-Dimethoxy-4-iodophenethylamine (also known as 2C-I and "Smiles") is a psychedelic substance of the phenethylamine class. It is a member of the 2C-x family of psychedelic phenethylamines, all of which were derived from the systematic modification of the mescaline molecule. 2C-I was first synthesized and investigated for human activity by Alexander Shulgin in 1976 and later described in his 1991 book PiHKAL ("Phenethylamines I Have Known and Loved").

    Perspectives

    “The 2C family can feel like entirely different drugs depending on how you administer them. The oral ROA is an entirely different experience than insufflatedβ€”you come up fast and hard, faceplanted into the experience from the top of a 12 story building.”

    “I was present at a group meeting, but was only an observer. With zero milligrams of 2C-I, I was able to get to a delightful plus 2.5 in about five minutes after I arrived at your place, and absorbed the ambience of the folks who had actually imbibed the material. My level lasted about four hours and came down at about the same time as did the others. There were no after-effects experienced except for a pleasant languor.”

    “Overall, on this dose this was a fairly mild and pleasant experience. It didn't have the depth of 2C-E, or a great deal of excitement, but for a gentle afternoon sojourn it was positive and enjoyable.”

    Dose Information TripSit PsychonautWiki

    ROA Light Common Strong Heavy
    Oral 5-10mg 10-20mg 20-30mg 30mg+
    Light Common Strong Heavy

    Onset, Duration & After-effects TripSit PsychonautWiki

    ROA Onset Comeup Peak Offset After Effects Total
    Oral 12-48 min 48-90 min 3-5 hrs 2-3 hrs 6-24 hrs 5-10 hrs

    Effect Profile

    650 reports

    Scores (1–10) curated from multiple sources:

    • Effect keyword matching from PsychonautWiki catalog
    • Validated against 508 Erowid trip reports
    • Weighted by importance: core (×3), major (×2), minor (×1)

    Full methodology

    Psychedelic 8.8
    Intense+ 9/10

    Strong visuals, headspace, auditory effects, and body load

    Visual Intensity ×3
    10
    external hallucinations internal hallucinations autonomous entities colour enhancement drifting synaesthesia +7 more
    Headspace Depth ×3
    10
    emotion enhancement perspective alterations confusion time distortion
    Auditory Effects ×1
    10
    auditory distortion auditory enhancement auditory hallucinations auditory hallucination synaesthesia
    Body Load / Somatic Effects ×1
    10
    nausea temperature regulation suppression muscle tension increased heart rate

    Tolerance

    Build-up develops rapidly after a single use
    Reset 7–14 days for baseline

    Tolerance Decay

    Half tolerance 5d Baseline ~10d

    Subjective tolerance to classical psychedelics rises acutely and tends to decrease substantially over 3–7 days and return near baseline by 1–2 weeks; cross‑tolerance across serotonergic psychedelics is common, though exact ratios are not quantified.

    Effects Erowid Bluelight

    Aggregated from 508 Erowid and 142 Bluelight experience reports

    Positive Effects 77

    Visual Distortions 77.5% 79%
    Color Enhancement 53.7% 87%
    Stimulation 50.7% 86%
    Surface Breathing 48.0% 86%
    Music Enhancement 45.5% 90%
    Euphoria 42.1% 88%
    Awe 38.0% 84%
    Empathy 36.9% 82%
    Visual Trails 36.0% 87%
    Tactile Enhancement 30.5% 85%
    Introspection 28.0% 85%
    Joy 28.0% 88%
    Focus Enhancement 25.8% 82%
    Closed-Eye Visuals 24.7% 93%
    Body High 24.4% 85%
    Insight 24.0% 84%
    Patterning 22.0% 86%
    Morphing 22.0% 87%
    Melting/flowing 22.0% 87%
    Geometric Imagery 20.0% 86%

    Adverse Effects 42

    Anxiety 43.8% 86%
    Confusion 30.3% 85%
    Nausea 29.7% 85%
    Body Load 22.0% 84%
    Tremor 16.0% 83%
    Muscle Tension 15.2% 81%
    Jaw Clenching 12.0% 85%
    Restlessness 12.0% 83%
    Paranoia 12.0% 75%
    Headache 11.6% 68%
    Fear 8.0% 89%
    Depersonalization 8.0% 81%
    Stomach Cramps 6.0% 80%
    Panic 6.0% 84%
    Increased Heart Rate 5.9% 70%
    Memory Suppression 5.5% 77%
    Sweating 5.2% 84%
    Social Anxiety 4.0% 85%
    Dizziness 4.0% 80%
    Vertigo 4.0% 82%

    Combinations TripSit

    Cross-Check 2C-I with another substance

    Trip Reports Effect Index

    Community Trip Reports

    Anecdotal first-person accounts from Reddit, Erowid, and Bluelight. Click a source to expand. Reports are harm-reduction context, not medical guidance.

    Erowid 8 reports 3 positive 3 neutral 2 cautionary visit
    Awesome Clarity positive exp #53320

    On one of the last days of this past spring semester, as a celebration of the onset of summer vacation, my friends and I decided it would be fun to trip on acid. However, our acid contact had gone out of town for the day, so I went to find some mushrooms instead.

    Mystica Materiali · 20 mg oral / 20 mg oral / repeated smoked
    Further Psychic Repairs Through Psychedelics positive exp #46937

    Recently I've begun a significant life-changing process of self-betterment through a psychedelic regimen, by clearing my head space of negativity and re-opening my imagination, internal imaging capabilities, and routes of self-expression.

    Xorkoth · 19 mg oral / oral
    Fantastic Dance Drug positive exp #11582

    New Year's Eve had arrived and I was in the mood for something different. Our destination was a small rave, so I was looking for something that would give me energy and be fun to dance to without leaving me too incoherent.

    TeaVeeEye · 15 mg oral
    Holy Shit, I Don't Know Who I Am! neutral exp #47590

    Prior to this experience there were 3 others, all which had mild similar experience to those of others. But this one went terrible wrong or really good depending upon how you look at it. I took 22mg crystal form.

    ChaosX · 22 mg oral
    Detailed Analysis of a Mindbending First Trip neutral exp #99070

    Method: 3 doses; insufflation [00:00], oral (under tongue[00:30]) + (ingestion[02:00]) Length: 15 hours; 23:30pm? to 15:30pm Recovery: 5 days + (still somewhat recovering) Date: 28th December 2012 This is my first and only hallucinogenic experience to date, bar a terrible bout of misplaced anxiety and disgust on synthe...

    ninpo · insufflated / sublingual / sublingual / smoked
    Like Consensual Rape neutral exp #98368

    I had tried MDMA 2011-2012 but only properly experienced it in April, and since then have had it many times and Mkat/similar. With that, IΒ’ve started using nitrous oxide and weed occasionally too, but really am interested in exploring what drugs have to offer, especially with altered states of consciousness.

    Aslan · 60 mg oral / repeated smoked / repeated inhaled / 60 mg oral
    A Backward-Resonating Experience cautionary exp #53057

    It had been a strange few weeks and months, a time of transition, confusion, and angst. Time seemed to be throwing a curveball backward at me from some point, shrouded and viscerally ominous, in the future.

    bug · 20 mg oral
    A Warning on Unpredictability cautionary exp #89260

    I'm a long-time dabbler in psychedelics, but have never before felt the compulsion to post an experience. I've tried marijuana, salvia, DXM, Woodrose-derived LSA, LSD, shrooms, 2C-E, 2C-I, 4-AcO-DMT, 5-Meo-DMT, 5-Meo-DIPT, ayahuasca and catcus-derived mescaline --- but I've never done a dosage, on anything, that would...

    Lillys Dolphin · 800 mg oral / 10 mg oral
    Bluelight 8 threads 2 positive 5 neutral 1 cautionary visit
    2c I Second Time And Best Trip Ever Long positive

    Friday night at college and my boy got some acid, and I missed the movie I wanted to see. Thank goodness he has some extra 2C-I around. I wasn't sure I really wanted to trip on it again because my first experience was unpleasant until I smoked weed mid-peak.

    scraped 2026-03-14
    2c I – First Time Relatively Inexperienced – Fantastic But positive

    2C-I – First time, relatively inexperienced, 20mg – Fantastic, BUT … Story Background This is one of a number of stories a friend found hand-written on notepad paper and stuffed inside a chemistry book at the University library.

    scraped 2026-03-14
    2c I 3rd Time Preconceptions Of The Universe Unfold neutral

    It was about 9:30 when I decided to introduce someone into the wonderful world of hallucinogens with my own desire to attempt to increase my connectivity and understanding of this man.

    scraped 2026-03-14
    2c I First Time Quite Nice neutral

    2c-i - first time - quite nice --------------- introduction --------------- it's 12:35 am and i have just gotten home from work and ate a sandwhich i picked up from wendy's. i worked from 6pm-midnight. i took the 16mg dose at 10:15 am.

    scraped 2026-03-14
    2ci Catastrophic Stupidity Dosage Wrong By Factor Of neutral

    Me: 120mg 2ci, 125lbs Boyfriend: 130mg 2ci, round 30mg 2ce, 160lbs. Empty stomachs Both somewhat experienced trippers, my boyfriend more so than me. So this is a long report; if you don't want to read all of it here are the basics: Planning a light trip, we dose the 2ci wrong by a factor of ten - yes TEN.

    scraped 2026-03-14
    2c I First Time What A 40mg Trip On 2c I Is Like cautionary

    This should be a lesson for all of you to NEVER EVER eyeball a dose. If this had been a more dangerous substance, I could have ended up the hospital. After the trip, I took the small plastic baggy that the contents came in and it measured out to 62mg's. So I took around 40mg's+.

    scraped 2026-03-14

    Bluelight Reference Guide Bluelight

    Phenethylamines The Big & Dandy 2C-I Thread - Take Two

    Welcome to the Big & Dandy 2C-I Thread 2C-I = 2,5-dimethoxy-4-iodophenethylamine ; structural formula on the left ; 2C-I powder on the right (photo courtesy of the ruling Erowid.org) External Information Links: Erowid 2C-I Vault (experience reports) PIHKAL Entry for 2C-I Wikipedia entry Previous Big & Dandy Thread: Fir...

    Read full thread on Bluelight β†’

    PiHKAL / TiHKAL Shulgin

    PiHKAL #33: 2C-I

    “I was present at a group meeting, but was only an observer. With zero milligrams of 2C-I, I was able to get to a delightful plus 2.5 in about five minutes after I arrived at your place, and absorbed the ambience of the folks who had actually imbibed the material. My level lasted about four hours and came down at about the same time as did the others. There were no after-effects experienced except for a pleasant languor.”

    β€” Alexander Shulgin, PiHKAL (with 0 mg)

    Helpful Links