DOI
2,5-dimethoxy-4-iodoamphetamine
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DOI (2,5-dimethoxy-4-iodoamphetamine) is a synthetic psychedelic of the phenethylamine class. It is the most potent member of the DOx amphetamine family, related to DOM. It activates serotonin receptors in the brain, producing the visual distortions and altered cognition characteristic of classical psychedelics.[1]
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First synthesized in 1973 as part of a study of DOM analogs,[2] DOI was later characterized by Alexander Shulgin, who documented the dose range and duration that researchers still cite.[3] Its radioiodinated form became the standard tool for mapping serotonin receptor sites in the late 1980s.[4] Today it remains largely a laboratory compound, with negligible recreational adoption.
Subjective effects include geometric visual patterns, color enhancement, physical stimulation, emotional warmth, and profound time alteration. The experience is defined by endurance — it unfolds across an entire waking cycle, passing through multiple moods and energy levels, more physically activating than tryptamine psychedelics like psilocybin.[3] Vasoconstriction, muscle tension, and exhaustion from extended wakefulness are characteristic unsought effects.
DOI produces no physical dependence, and no confirmed human fatality from pure DOI has been published.[5] The main risks are sustained cardiovascular stress from vasoconstriction, psychological crises that cannot be shortened, and misidentification — DOx compounds have been sold as LSD on blotter paper.[6] Human pharmacokinetic data are entirely absent; current understanding rests on animal research and limited self-report.
History[edit]
Discovery
DOI was first synthesized in 1973 as part of a systematic study of iodine-substituted analogs of DOM.[2] Alexander Shulgin later characterized the compound through personal bioassay, documenting the dose range and duration that remain the primary human reference.[3]
Scientific Significance
In the late 1980s, a radioiodinated form of DOI was developed and became the standard tool for studying serotonin receptor sites.[4] This made DOI indispensable in laboratory research — used in receptor binding studies, functional assays, and as the primary trigger in animal models of hallucinogenesis.[5] Recent work has explored its anti-inflammatory properties[7][8] and the possibility of separating its therapeutic effects from its hallucinogenic properties.[1]
Recreational Context
Recreational use has remained negligible — extreme duration, significant body load, and more manageable alternatives limit appeal. The primary harm concern is misidentification: DOx compounds have appeared on blotter paper sold as LSD at music festivals, documented at the 2014 Boom Festival in Portugal.[6]
The name "DOI" follows DOx series nomenclature: Dimethoxy (the 2,5-dimethoxy pharmacophore), O (the oxygen-bearing substitution pattern), and I (iodine at position 4). The compound has almost no street reputation — it exists primarily in the cultural awareness of psychedelic researchers and a small circle of experienced psychonauts who regard it as an endurance test rather than a recreational choice.
Chemistry[edit]
DOI belongs to the DOx series — a family of synthetic psychedelics built on an amphetamine backbone, with methoxy groups at positions 2 and 5 of the phenyl ring and a halogen at position 4, derived from DOM.[9]
DOI carries iodine at position 4 — the heaviest halogen used in the series, which gives it the highest serotonin receptor binding affinity of any DOx compound. Its molecular formula is C₁₁H₁₆INO₂ (321.15 g/mol).
Pharmacology[edit]
Mechanism of Action
DOI activates serotonin receptors in the brain directly[10] — unlike amphetamine, it does not release dopamine or serotonin from neurons.[11] The hallucinogenic effect depends on a specific signaling pathway within those receptors that other serotonin activators don't use.[1] This is why some compounds that activate the same serotonin receptor produce no hallucinations at all.
DOI also strengthens dopamine signaling in certain brain regions through a receptor complex shared with LSD,[12] and triggers release of stress hormones, oxytocin, and prolactin.[13]
Pharmacokinetics
No controlled human pharmacokinetic studies have been published for DOI. Onset occurs 1–2 hours after oral ingestion.[3] The extreme duration likely results from the amphetamine backbone resisting enzymatic breakdown — the same structural feature that separates the DOx series from the shorter-acting 2C-x compounds.inferred
Neuroscience[edit]
Where It Acts
DOI activates serotonin receptors concentrated on neurons in the outer layers of the neocortex, triggering production of proteins associated with brain rewiring.[14] A single dose produces measurable increases in brain volume across sensory and association areas within 24 hours, with improved cognitive flexibility lasting at least one week.[15] In the claustrum — a thin brain structure thought to integrate conscious experience — DOI's effects are driven by a different serotonin receptor than elsewhere in the brain.[16]
Why It Matters
DOI belongs to a class of compounds called psychoplastogens — substances that promote structural and functional reorganization of the brain.[17] Research has shown that the signaling pathway producing hallucinations and the pathway producing brain rewiring are separate,[1] opening the possibility of compounds that deliver therapeutic brain changes without hallucinations.
The mechanistic basis for DOI's extreme duration remains unknown — slow elimination, persistent receptor occupancy, and sustained downstream signaling are all plausible. Whether the structural brain changes observed in animals translate to humans is unconfirmed. The relative contribution of different serotonin receptor types to the human subjective experience remains an open question raised by the claustrum findings.[16]
Subjective Effects[edit]
DOI is an endurance psychedelic. The experience unfolds across an entire waking cycle — distinct phases, each with its own mood, energy, and perceptual character. Physical stimulation runs through the whole arc, and the body bears the full weight of the experience long after the peak has passed.
Compared to LSD, DOI is more physically activating and carries greater body load — vasoconstriction, muscle tension, and fatigue are more prominent than the intricate cognitive headspace LSD produces.[3] Where LSD demands a committed day, DOI demands an entire waking cycle. Most experienced psychedelic users treat it as a rare undertaking.
Effect Grid
At common doses (1.5–2.5 mg oral), the full psychedelic experience manifests: pronounced visual drifting, color alteration and enhancement, symmetrical texture repetition, after-images and tracers, and object transformations. Thought connectivity increases substantially — novel conceptual associations, pattern recognition enhancement, and analysis enhancement dominate the cognitive space. Emotional enhancement and empathy enhancement are prominent. Time alteration becomes significant.
Physically, vasoconstriction intensifies (cold hands and feet), muscle tension becomes persistent, bruxism may appear, and appetite is fully suppressed. Stimulation and wakefulness are pronounced throughout. Nausea is possible during the extended come-up.
The total experience spans 16–24 hours. Sleep is impossible for the first 12–16 hours. A full-day and overnight commitment in a safe environment is required.
Modeled from the effect's dose-dependence curve — not per-substance measurements.
Visual drifting · Music enhancement · Visual breathing · Perspective distortion · Symmetrical texture repetition · Tracers · Depth perception distortion · Auditory enhancement · Environmental patterning · Light sensitivity · Visual morphing · Holotropic state · After-images · Visual diffraction · Touch enhancement · Auditory distortion · Dreaming suppression · Peripheral vision distortion · Sound sensitivity · Spatial disorientation · Visual melting · Visual acuity enhancement · Auditory misinterpretation · Ganzfeld effect · Peripheral misidentification · Proprioceptive distortion · Sleep-transition hallucinations · Vestibular distortion · Visual haze / noise · Visual processing acceleration · Synesthesia · Visual magnification · Flashbacks · Object transformations · External hallucinations · Visual recursion · Internal hallucinations · Object activation · Perspective hallucinations · Auditory hallucinations · Environmental orbism / cubism · Visual flipping · Visual scenery slicing · Persisting hallucinations
Symmetrical texture repetition · Tracers · Depth perception distortion · Auditory enhancement · Environmental patterning · Light sensitivity · Visual morphing · Holotropic state · After-images · Visual diffraction · Touch enhancement · Auditory distortion · Dreaming suppression · Peripheral vision distortion · Sound sensitivity · Spatial disorientation · Visual melting · Visual acuity enhancement · Auditory misinterpretation · Ganzfeld effect · Peripheral misidentification · Proprioceptive distortion · Sleep-transition hallucinations · Vestibular distortion · Visual haze / noise · Visual processing acceleration · Synesthesia · Visual magnification · Flashbacks · Object transformations · External hallucinations · Visual recursion · Internal hallucinations · Object activation · Perspective hallucinations · Auditory hallucinations · Environmental orbism / cubism · Visual flipping · Visual scenery slicing · Persisting hallucinations
Wakefulness · Body scan awareness · Spontaneous body sensations · Body high · Insomnia · Muscle tension · Physical fatigue · Dehydration sensation · Dry mouth · Heart rate perception changes · Restlessness · Tingling / electric sensations · Nausea · Excessive sweating · Bodily pressures · Body schema distortion · Breathing alteration · Dizziness · Motor control impairment · Tactile euphoria · Vibrations / buzzing · Abnormal heartbeat · Involuntary body movements · Diarrhea · Sexual arousal enhancement · Bruxism · Headache · Laughter fits · Nasal congestion · Nystagmus (eye wobbles) · Trembling · Salivation · Vomiting · Motor control enhancement · Seizure threshold reduction · Bodily dissociation · Tactile hallucination
Body high · Insomnia · Muscle tension · Physical fatigue · Dehydration sensation · Dry mouth · Heart rate perception changes · Restlessness · Tingling / electric sensations · Nausea · Excessive sweating · Bodily pressures · Body schema distortion · Breathing alteration · Dizziness · Tactile euphoria · Vibrations / buzzing · Abnormal heartbeat · Involuntary body movements · Diarrhea · Sexual arousal enhancement · Bruxism · Headache · Laughter fits · Nasal congestion · Nystagmus (eye wobbles) · Trembling · Salivation · Vomiting · Motor control enhancement · Seizure threshold reduction · Bodily dissociation · Tactile hallucination
Pattern recognition enhancement · Immersion enhancement · Aesthetic enhancement · Introspection enhancement · Openness enhancement · Thought acceleration · Cognitive euphoria · Memory suppression · Cognitive flexibility · Cognitive impairment · Multiple thought streams · Creativity enhancement · Thought loops · Analysis enhancement · Cognitive fatigue · Confusion · Focus suppression · Increased nature relatedness · Information processing suppression · Memory fragmentation · Thought disorganization · Humor enhancement · Focus enhancement · Information processing enhancement · Motivation enhancement · Analysis suppression · Cognitive dysphoria · Memory replays · Motivation suppression · Synchronicity · Language suppression · Delusions · Amnesia · Delirium
Introspection enhancement · Openness enhancement · Thought acceleration · Cognitive euphoria · Memory suppression · Cognitive flexibility · Cognitive impairment · Multiple thought streams · Creativity enhancement · Thought loops · Analysis enhancement · Cognitive fatigue · Confusion · Focus suppression · Increased nature relatedness · Information processing suppression · Memory fragmentation · Thought disorganization · Humor enhancement · Focus enhancement · Information processing enhancement · Motivation enhancement · Analysis suppression · Cognitive dysphoria · Memory replays · Motivation suppression · Synchronicity · Language suppression · Amnesia · Delirium
Simultaneous emotions · Empathy enhancement · Euphoria · Irritability · Catharsis · Dysphoria
Catharsis · Dysphoria
Disinhibition · Communication suppression · Social connection · Trust enhancement · Flow state · Sociability enhancement · Automaticity · Ego inflation · Social disconnection · Boundary dissolution · Cognitive disconnection · Ego dissolution · Identity alteration
Flow state · Sociability enhancement · Automaticity · Ego inflation · Social disconnection · Boundary dissolution · Cognitive disconnection · Ego dissolution · Identity alteration
Time cessation
Transpersonal memory access · Transpersonal visions · Death-rebirth sequence · Voidness
Recursive awareness
Timeline
First alerts emerge 1–2 hours after ingestion: subtle mood shift, mild stimulation, slight color brightening. Easily mistaken for placebo at this stage.
Effects build gradually over 1. 5–3 hours. Visual enhancement, body load (vasoconstriction, muscle tension), and thought acceleration emerge progressively.
Maximum intensity sustained for 4–6 hours. Full visual phenomena, profound thought connectivity, emotional enhancement, and significant body load. The extended peak is DOI's defining temporal characteristic.
Effects diminish gradually but remain clearly perceptible for 4–7 hours. Visual phenomena recede before cognitive and stimulant effects. Body load persists.
Residual stimulation, mild visual enhancement, and wakefulness persist 2–4 hours beyond subjective plateau. Muscle tension and appetite suppression continue.
Residual mood alteration, mild cognitive fatigue, and physical recovery extend 8–24 hours post-resolution. Sleep quality may remain disrupted for 1–2 nights.
⚠ Do not drive or operate machinery until after a full night of restorative sleep following complete resolution of all effects.
Safety[edit]
- Acute toxicity
- Low
- Chronic toxicity
- Negligible
- Withdrawal
- None
- Tolerance buildup
- rapid
- Tolerance reset
- 12 days
- Physical
- None
- Psychological
- Negligible
- Compulsive redosing
- Negligible
- Dose escalation
- Negligible
- Cross-tol.
- LSD · psilo · mesc
Toxicity
No lethal dose has been established for DOI in any species, and no confirmed human death from pure DOI ingestion has been published.[5]
Cardiovascular Effects
DOI causes blood vessel constriction by activating serotonin receptors in vessel walls.[18] This produces sustained cardiovascular stress — elevated blood pressure and reduced blood flow — lasting far longer than most psychedelics. Anyone with pre-existing heart or blood pressure conditions faces meaningful risk.
Adulteration Risk
The most dangerous real-world scenario involves misidentification. DOx compounds have been distributed on blotter paper sold as LSD.[6] A user expecting LSD's shorter onset may redose when nothing appears to happen, potentially reaching dangerous doses — related NBOMe compounds have caused fatalities,[19] though they are pharmacologically distinct from DOI.
Psychological Risks
The extreme duration is DOI's defining psychological hazard — a difficult experience cannot be waited out, and distress can persist for many hours with no option for quick resolution. Specific risks include sustained anxiety, paranoia, and psychological crisis escalating over time, compounded by sleep deprivation and physical exhaustion.
No cases of persistent visual disturbance specific to DOI have been published. Serotonin receptor-activating psychedelics as a class can trigger psychotic episodes in predisposed individuals.inferred
Tolerance & Dependence
Tolerance builds within 24 hours of a single dose, driven by downregulation.[20] Daily dosing produces progressive tolerance; 48-hour spacing allows full recovery.[21] Full cross-tolerance exists between DOI and LSD, while non-hallucinogenic serotonin agonists produce no cross-tolerance — suggesting tolerance is specific to the hallucinogenic signaling pathway.[20]
No evidence of physical dependence, withdrawal, or compulsive use has been published.
Drug Interactions
Serotonergic Combinations
Tramadol combined with DOI creates significant risk of serotonin syndrome — a dangerous state of overactivated serotonin signaling causing elevated body temperature, rapid heart rate, high blood pressure, muscle jerking, and seizures.safety citation needed
MAOIs block the breakdown of serotonin in the body, dramatically amplifying any serotonergic compound. Combining an MAOI with DOI carries severe theoretical risk even without a specific reported case.safety citation needed
SSRIs and SNRIs raise baseline serotonin levels. Chronic SSRI use may reduce DOI's effects; combining them acutely adds serotonergic risk.
Vasoconstrictive Combinations
DOI's vasoconstriction[18] is worsened by triptans, ergotamines, or high-dose stimulants. The very long duration means vascular stress accumulates over an extended period.
Cannabis
No published data exist on DOI combined with cannabis. Both compounds can amplify anxiety at high doses; additive distress is plausible but unconfirmed.
Contraindications
No published contraindication data specific to DOI exist. The following are inferred from mechanism:
- Heart or blood pressure conditions: sustained vasoconstriction and stimulation over the full duration pose meaningful cardiovascular risk
- Personal or family history of psychotic disorders: serotonin receptor activation can trigger psychotic episodes in predisposed individuals
- Seizure disorders: serotonin receptor activation may lower seizure threshold
- Concurrent serotonergic medication: SSRIs, SNRIs, MAOIs, tramadol — serotonin syndrome risk
- Pregnancy: vasoconstriction poses theoretical risk to placental blood flow; no reproductive toxicity data exist
Harm Reduction[edit]
Forms & Identification
DOI's primary identification challenge is distinguishing it from LSD on blotter paper. Both are active at similar doses and can be laid on identical carrier media. The key differentiator is taste: DOI on blotter often produces a noticeable bitter or metallic flavor, while LSD is tasteless. Taste alone is not a reliable identification method.
Reagent testing provides important but incomplete information. An Ehrlich test that shows no reaction suggests the substance is not an indole — ruling out LSD — which should raise immediate suspicion if the material was sold as LSD. Quantitative testing through a drug checking service is the only way to confirm identity and dose.
Guidelines
- Test all material with reagent kits before ingestion — verify it is not a more dangerous NBOMe compound
- Start at the low end of the dose range; the extremely long duration makes titration impractical once committed
- Clear a full 36-hour window: 24 hours for the experience plus 12 hours for sleep recovery
- Prepare food, water, and comfortable clothing in advance — appetite may be suppressed but hydration and nutrition matter over many hours
- Keep the environment temperature-controlled; vasoconstriction can make cold feel more intense
- Have a trusted person aware of the timeline who can check in periodically
- Do not redose if effects haven't appeared within 2 hours — onset can be slow
- Avoid physical exertion during the experience; vasoconstriction increases cardiovascular demands
Set & Setting
DOI's duration demands fundamentally different preparation than shorter psychedelics. A full day and night must be cleared of obligations — no driving, work, or childcare for at least 24 hours. The setting must remain safe and accessible for the entire duration, including through the early morning hours after many hours of altered consciousness.
A trusted sitter who understands the timeline is strongly recommended. No single person can maintain attentive presence for 20+ hours — multiple sitters or arranged shifts are advisable. Mental preparation should include explicit acceptance that the experience cannot be shortened once begun.
Aftercare & integration. The primary aftercare need after DOI is physical recovery. Sleep comes first — the body has been awake and stimulated for many hours under vasoconstriction and elevated stress hormones. Do not attempt to process the experience intellectually until adequate rest has been obtained.
In the 48 hours following, expect fatigue, emotional sensitivity, and possible low mood as neurotransmitter systems rebalance. Light meals, hydration, gentle movement, and contact with trusted people support recovery. Journaling and integration conversations are best deferred 2–3 days until cognitive baseline returns.
If distressing psychological content persists beyond one week, or if perceptual disturbances do not fully resolve, consult a mental health professional experienced with psychedelic experiences.
Recovery & Support
DOI does not produce physical dependence or withdrawal. Compulsive use is essentially unknown given the aversive duration and body load. If repeated use is occurring despite negative consequences, the underlying motivation is more likely psychological avoidance or compulsive novelty-seeking than pharmacological dependence.
Support resources for problematic psychedelic use include the Fireside Project (62-FIRESIDE / 623-473-7433), the MAPS integration therapist directory, and local harm reduction organizations. Psychedelic integration circles — peer support groups for processing difficult experiences — are available in many cities and online.
Recovery resources, crisis lines, and support pathways → View all
Emergency Response
Recognizing an emergency: Distinguish discomfort from danger. Anxiety, restlessness, and unpleasant body sensations are expected and not emergencies. Seek immediate help for: chest pain or pressure, numbness or discoloration in the extremities (suggesting severe vasoconstriction), seizure activity, complete disconnection from reality with self-harm risk, or expressed suicidal intent.
Immediate steps:
- Move the person to a calm, safe environment
- Speak in short, reassuring sentences — remind them what they took and that it will end
- If chest pain or extremity numbness is present, call emergency services immediately
- Do not physically restrain unless there is immediate danger of self-harm
- Monitor breathing and consciousness
What to tell the dispatcher: Name the substance (DOI or "a DOx amphetamine psychedelic"), the approximate dose if known, the time of ingestion, and current symptoms. Good Samaritan laws in many jurisdictions protect callers from drug-related prosecution when seeking medical help.
Legal Status[edit]
DOI occupies an unusual regulatory position: despite potent psychoactive properties and decades of research use, it remains unscheduled in several major jurisdictions as of May 2026.
| Jurisdiction | Classification | Key provisions |
|---|---|---|
| United States | Currently unscheduled (federal) | DEA proposed Schedule I placement April 2022;[22] ALJ hearing stayed June 2024 pending district court matter.[23] May trigger Federal Analogue Act if intended for human consumption. |
| United Kingdom | Controlled (Class A equivalent) | Scheduled under Misuse of Drugs Act 1971 phenethylamine catch-all clause.[24] Additionally covered by Psychoactive Substances Act 2016. |
| Canada | Schedule III (CDSA) | Controlled as amphetamine analogue under the Controlled Drugs and Substances Actcitation needed |
| Sweden | Schedule I (Förteckning I) | Classified as narcotics effective August 30, 2007citation needed |
| Finland | Banned from consumer market | Classified as psychoactive substance prohibited from consumer salecitation needed |
| Australia | Tentatively unscheduled | Not listed in SUSMP as of available data; requires verification against current schedulecitation needed |
Legal status changes frequently. This information reflects available data as of May 2026 and is not legal advice — verify the current status in any jurisdiction before acting on it.
references
- [1] ^abcdXu Z, Wang H, Yu J et al. (2026) Psychedelics elicit their effects by 5-HT2A receptor-mediated Gi signalling — Nature doi:10.1038/s41586-025-10061-7
- [2] ^abCoutts RT, Malicky JL (1973) The Synthesis of Some Analogs of the Hallucinogen 1-(2,5-Dimethoxy-4-methylphenyl)-2-aminopropane (DOM). — Canadian Journal of Chemistry doi:10.1139/v73-210
- [3]
- [4] ^abMcKenna DJ, Peroutka SJ (1989) Differentiation of 5-hydroxytryptamine2 receptor subtypes using 125I-R-(-)2,5-dimethoxy-4-iodo-phenylisopropylamine and 3H-ketanserin. — Journal of Neuroscience PMID:2795135
- [5] ^abcCanal CE, Morgan D (2012) Head-twitch response in rodents induced by the hallucinogen 2,5-dimethoxy-4-iodoamphetamine: a comprehensive history, a re-evaluation of mechanisms, and its utility as a model — Drug Testing and Analysis doi:10.1002/dta.1333
- [6] ^abcMartins D, Barratt MJ, Pires CV et al. (2017) The detection and prevention of unintentional consumption of DOx and 25x-NBOMe at Portugal's Boom Festival — Human Psychopharmacology doi:10.1002/hup.2608