2C-E

2C-E (2,5-dimethoxy-4-ethylphenethylamine) is a synthetic psychedelic phenethylamine of the 2C structural class, first synthesized and characterized for human activity by Alexander Shulgin in 1977 and documented in his 1991 reference text PiHKAL (Phenethylamines I Have Known and Loved) as entry number 24. Shulgin designated 2C-E as one of the "magical half-dozen," a personal ranking of the six most important phenethylamine compounds he had investigated, alongside mescaline, 2C-B, 2C-T-2, 2C-T-7, and DOM [1]. The compound acts primarily as a partial agonist at the serotonin 5-HT2A, 5-HT2B, and 5-HT2C receptors, with binding affinities in the low-nanomolar to mid-nanomolar range at the 5-HT2A subtype (Ki approximately 4.5 to 44 nM depending on assay and radioligand) and weak inhibition of the serotonin and norepinephrine membrane transporters [2, 3]. The receptor binding profile places 2C-E within the classical serotonergic psychedelic pharmacology shared by mescaline, psilocybin, and lysergic acid diethylamide, though the phenethylamine scaffold and 4-position ethyl substituent confer distinct potency, duration, and subjective effect characteristics relative to both tryptamine and ergoline psychedelics.

A defining pharmacological characteristic of 2C-E is an unusually steep dose-response curve. Shulgin reported a broad effective dose range of 10 to 25 mg orally, but noted that small increments within this range produce disproportionately large increases in subjective effect intensity [1]. Doses of 10 mg are generally described in the research literature as producing moderate perceptual enhancement with manageable intensity, while doses of 25 to 30 mg have been associated with overwhelming psychedelic experiences, pronounced anxiety, and loss of behavioral control. This steep dose-response relationship has direct safety implications and has contributed to documented poisoning events and fatalities in uncontrolled settings.

The only systematic human pharmacological study of 2C-E is the Papaseit et al. (2020) observational investigation of ten recreational users self-administering oral doses of 6.5 to 25 mg, which characterized the acute physiological, subjective, and oral-fluid pharmacokinetic profile [4]. The study reported peak subjective effects at approximately 2 hours, duration of action of 8 to 12 hours, dose-dependent increases in heart rate and body temperature, and the prototypical psychedelic effect profile including visual hallucinations, perceptual alterations, euphoria, and somatic symptoms. Oral fluid pharmacokinetics showed a Cmax of approximately 5.8 ng/mL at a Tmax of 2 hours.

Metabolism of 2C-E proceeds principally through oxidative deamination catalyzed by monoamine oxidase A and B (MAO-A, MAO-B), with minor contributions from cytochrome P450 2D6, and through O-demethylation [5]. The compound is not a substrate for monoamine-releasing mechanisms and does not produce appreciable dopamine transporter inhibition, distinguishing it pharmacologically from amphetamine-type stimulants despite the shared phenethylamine backbone.

2C-E has no approved medical indication in any jurisdiction. It was placed in Schedule I of the United States Controlled Substances Act on July 9, 2012, under the Synthetic Drug Abuse Prevention Act, and is controlled in the United Kingdom (Class A), Canada (Schedule III), Germany (Anlage I), Australia, and numerous other jurisdictions [6]. The compound is available from research chemical suppliers for in vitro and preclinical investigation; investigators should confirm identity and purity on every lot and must comply with applicable controlled substance regulations. This monograph reviews the chemistry, synthesis, receptor pharmacology, pharmacokinetics, preclinical and observational human evidence, toxicology, and a comparative assessment of five structurally or mechanistically related compounds against 2C-E on five competency standards.