2C-I

2C-I (2,5-dimethoxy-4-iodophenethylamine) is a synthetic psychedelic of the phenethylamine class and a member of the "2C" family first synthesized and described by the chemist Alexander Shulgin, who reported it in 1977 and later in his 1991 book PiHKAL. It is a close relative of 2C-B and 2C-E, differing in the chemical group at one position on the molecule (in this case iodine). It is usually taken orally as a powder or in capsules and is used recreationally as a "new psychoactive substance." Importantly, 2C-I is sometimes confused with 25I-NBOMe (nicknamed "Smiles" or "N-bomb"), a chemically different and considerably more dangerous drug — the two are not the same.

Like the other 2C compounds and classic psychedelics such as 2C-B and LSD, 2C-I produces its psychedelic effects mainly by activating serotonin 5-HT2A receptors in the brain, acting as a partial agonist at the 5-HT2 receptor family. Unlike stimulant-type phenethylamines, it is essentially inactive as a monoamine releaser and has negligible reuptake-inhibiting activity — its effects come from receptor activation rather than from flooding the brain with dopamine or serotonin.

2C-I is reported to produce visual enhancement and distortions, colour and pattern intensification, emotional openness, and a psychedelic headspace, generally described as milder and somewhat more stimulating than a classic strong psychedelic, and shorter and gentler than 2C-E. As with other 2C compounds a physical "body load" — restlessness, nausea, or muscle tension — can accompany the experience. Effects are taken orally and build over the course of an experience lasting several hours.

The most important safety point with 2C-I is the risk of confusion with 25I-NBOMe ("Smiles"), a different and much more toxic drug that has caused deaths and is sometimes sold as 2C-I; material sold under either name cannot be assumed to be what it claims. 2C-I itself can cause a raised heart rate and blood pressure, agitation, anxiety, nausea, and frightening psychological experiences, particularly at higher doses. Like 2C-E it is metabolized by monoamine oxidase (MAO) enzymes, so combining it with an MAO inhibitor can dangerously intensify its effects. Because purity and identity of powders vary, and because dose response differs between the 2C compounds, taking an unknown "2C" without confirmation of what it actually is carries real risk.

LSD-like hallucinations/visual distortion + MDMA-like empathy

delayed (redose-risk)

up to 8 hr

accidental overdose from delayed onset → redosing; sold misrepresented as MDMA/LSD

none

NFLIS 633 reports since 2003 (peak 95 in 2011–12; <5/yr 2023–25)