EPT
N-ethyl-N-propyltryptamine
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EPT (N-ethyl-N-propyltryptamine) is a synthetic psychedelic of the tryptamine class. It sits structurally between DET and DPT, sharing the same indole backbone with an asymmetric nitrogen substitution. It activates serotonin receptors in the brain, disrupting the normal filtering of sensory and cognitive input.[1]
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EPT first appeared on research chemical markets around 2016 — no synthesist, lab, or date of first preparation is on record, and the compound is absent from TiHKAL.[2] It was identified in seized products in Japan between 2017 and 2019,[3] which brought it into forensic tryptamine screening. It remains unscheduled in most countries and circulates in small quantities among research chemical users.
Subjective effects include geometric visual patterns, color enhancement, physical euphoria, cognitive clarity, and somatic warmth. The defining quality is an unusual split: vivid visual hallucinogenesis alongside near-sober analytical clarity — lighter and less overwhelming than DPT.[4] Anxiety, disorientation, and psychological overwhelm at higher doses are characteristic unsought effects.[5]
EPT does not produce physical dependence,[6] and its lethal dose is unknown — one postmortem case suspected EPT as a contributing factor, but causation was not established.[7]safety citation needed Psychological risks dominate: preserved clarity makes anxiety register sharply, and combining EPT with monoamine oxidase inhibitors can be life-threatening.[8] Only two scientific papers on EPT exist — everything else is inferred from related tryptamines, and no controlled human research has been done.
History[edit]
Emergence
EPT's origins are unrecorded — no synthesist, lab, or date of first preparation appears in the accessible literature. It is absent from TiHKAL, Alexander and Ann Shulgin's canonical reference for psychedelic tryptamines.[2] It first surfaced on research chemical markets around 2016, with early reports describing insufflation and smoking at 30–50 mg.[9]
Published research
The scientific literature on EPT consists of two papers. Chadeayne and colleagues solved its crystal structure in 2020.[10] Bergh and colleagues followed in 2024, identifying metabolites using human liver tissue and documenting a postmortem case in which EPT or a metabolite was suspected as a contributing substance.[7]
Forensic detection
EPT was identified in six seized products in Japan between 2017 and 2019, alongside related tryptamine analogs including 4-hydroxy-EPT.[3] It has since been incorporated into validated forensic extraction methods for tryptamine analogs in whole blood.[11]
EPT's closest structural analog, DPT, has a substantially longer history. DPT was studied as a psychotherapy aid for cancer patients and alcoholism at Spring Grove State Hospital during the 1970s.[12][6] EPT has inherited no aspect of this clinical lineage — it exists entirely within the novel psychoactive substance landscape.
Chemistry[edit]
Structural class
EPT belongs to the substituted tryptamine family — compounds built around the indole ring system. It carries one ethyl and one propyl group on the terminal nitrogen, making it a mixed N,N-dialkyl tryptamine that sits between DET (both chains two carbons) and DPT (both chains three carbons).
Molecular properties
| Molecular formula | C₁₅H₂₂N₂ |
| Molecular weight | 230.35 g/mol |
EPT has no chirality centers and exists as a single achiral form. Its crystal structure — solved from the hydrofumarate salt by X-ray diffraction — confirmed conformational flexibility in the N-ethyl chain and near-planar indole ring geometry.[10] No published data exist for melting point, solubility, or stability in either free-base or salt form.inferred
Pharmacology[edit]
Mechanism of action
No binding data exist for EPT at any receptor — all mechanistic understanding is inferred from DPT and the broader dialkyl tryptamine class. EPT is presumed to act primarily on serotonin receptors, the target that mediates psychedelic effects across the tryptamine class.[13] DPT fully mimics LSD and psilocybin in animal tests through serotonin receptor activation, an effect blocked entirely by selective serotonin receptor antagonists.[1][14]
DPT also activates a secondary serotonin receptor that modulates the hallucinogenic response,[15][16] and EPT likely shares this dual profile.inferred The size of the nitrogen substituents shifts which receptors a tryptamine favors and how it interacts with serotonin transporters.[17][18][13] EPT's mixed ethyl/propyl substitution falls between DET and DPT in steric size, but no measurements confirm where it lands.
Pharmacokinetics
EPT is broken down primarily by MAO-A (MAO-A), the enzyme that clears short-chain dialkyl tryptamines from the body.[19] In vitro testing using human liver microsomes identified three metabolic pathways: ring hydroxylation (the primary route), N-dealkylation, and carbonylation.[7] Insufflation bypasses the liver's first-pass breakdown, which likely explains why moderate insufflated doses are active without requiring an monoamine oxidase inhibitor.
Neuroscience[edit]
Where it acts
No neuroimaging, electrophysiology, or neuroplasticity data have been published for EPT — all mechanisms here are inferred from the serotonergic psychedelic class.inferred Serotonergic psychedelics disrupt the default mode network, reduce sensory filtering, and increase communication between normally segregated brain regions, producing ego dissolution, visual hallucinogenesis, and expanded associative thinking.
EPT's reported cognitive clarity during strong visuals raises an open question: does its receptor profile preserve analytical thinking while disrupting visual processing? This dissociation is not typically described for DPT or DMT.
Theoretical frameworks
One model proposes that psychedelics loosen the brain's high-level predictions, allowing sensory input to reshape perception from the bottom up. EPT's visual intensity alongside analytical clarity could represent a partial version of this — visual processing disrupted while higher-order thinking stays intact. Whether EPT also promotes structural changes in neurons is unknown, though its similarity to DPT and DMT — both confirmed for this in cell studies — suggests it probably does.inferred
- Does EPT produce neuroplasticity? No data exist. Testing in standard dendritogenesis assays would answer this directly.
- Does the cognitive clarity reflect a distinct neural signature? If EPT preserves prefrontal function while disrupting visual processing, this would represent an unusual dissociation among tryptamines.
- What accounts for EPT's duration? Receptor occupancy time correlates with duration differences among psychedelics — EPT's 2–4 hour window suggests shorter serotonin receptor residence than LSD but comparable to psilocin.
Subjective Effects[edit]
EPT compresses the psychedelic experience into a short window. Its defining quality is an unusual split: vivid closed-eye visuals alongside near-sober analytical clarity.[5] Environmental stimuli and anxious thoughts register with unusual sharpness rather than dissolving into the altered state.
Relative to DPT, its closest structural analog, EPT is described as less potent, less immersive, and less psychologically overwhelming.[4] Where DPT produces deep, enveloping states with significant cognitive disruption, EPT offers a lighter, more transparent experience — though this comparison rests on very few reports.
Effect Grid
At 40–80 mg insufflated, EPT produces its characteristic phenomenological signature: pronounced closed-eye geometry with highly detailed, repeated geometric designs coexisting with notable cognitive clarity. Color enhancement becomes distinct, and visual drifting and diffraction may appear with open eyes. Time alteration is commonly reported.
Body effects include stimulation, vibrations described as pleasurable and almost erotic, and a sense of bodily lightness. Some users report a "narcotic bliss" quality to the body high. Nausea occurs in a minority of experiences. Pupil dilation is expected.
The total experience lasts 2–4 hours. The unusual preservation of analytical capacity during visual hallucinogenesis distinguishes this range from comparable doses of DPT or DMT.
Modeled from the effect's dose-dependence curve — not per-substance measurements.
Geometry · Music enhancement · Tracers · Visual breathing · Visual diffraction · Symmetrical texture repetition · Auditory distortion · After-images · Auditory misinterpretation · Depth perception distortion · Environmental patterning · Light sensitivity · Perspective distortion · Sound sensitivity · Touch enhancement · Visual haze / noise · Visual morphing · Peripheral vision distortion · Proprioceptive distortion · Spatial disorientation · Vestibular distortion · Visual melting · Visual processing acceleration · Synesthesia · Visual acuity suppression · Internal hallucinations · Object transformations · External hallucinations · Object activation · Visual recursion · Auditory hallucinations · Visual flipping · Visual processing suppression
Visual diffraction · Symmetrical texture repetition · Auditory distortion · After-images · Auditory misinterpretation · Depth perception distortion · Environmental patterning · Light sensitivity · Perspective distortion · Sound sensitivity · Touch enhancement · Visual haze / noise · Visual morphing · Peripheral vision distortion · Proprioceptive distortion · Spatial disorientation · Vestibular distortion · Visual melting · Visual processing acceleration · Synesthesia · Visual acuity suppression · Internal hallucinations · Object transformations · External hallucinations · Object activation · Visual recursion · Auditory hallucinations · Visual flipping · Visual processing suppression
Nasal congestion · Nausea · Appetite suppression · Spontaneous body sensations · Wakefulness · Watery eyes · Bodily lightness · Dizziness · Dry mouth · Heart rate perception changes · Muscle tension · Physical fatigue · Tingling / electric sensations · Vibrations / buzzing · Bodily pressures · Body schema distortion · Dehydration sensation · Excessive sweating · Headache · Insomnia · Laughter fits · Restlessness · Trembling · Vasoconstriction · Sexual arousal enhancement · Involuntary body movements · Nystagmus (eye wobbles) · Vomiting
Spontaneous body sensations · Wakefulness · Watery eyes · Bodily lightness · Dizziness · Dry mouth · Heart rate perception changes · Muscle tension · Physical fatigue · Tingling / electric sensations · Vibrations / buzzing · Bodily pressures · Body schema distortion · Dehydration sensation · Excessive sweating · Headache · Insomnia · Laughter fits · Restlessness · Trembling · Sexual arousal enhancement · Involuntary body movements · Nystagmus (eye wobbles) · Vomiting
Introspection enhancement · Openness enhancement · Cognitive euphoria · Conceptual thinking · Immersion enhancement · Increased nature relatedness · Novelty enhancement · Thought connectivity · Creativity enhancement · Memory suppression · Thought acceleration · Cognitive impairment · Confusion · Focus suppression · Multiple thought streams · Thought disorganization · Analysis enhancement · Humor enhancement · Information processing enhancement · Cognitive fatigue · Information processing suppression · Memory fragmentation · Memory replays · Synchronicity · Thought loops
Immersion enhancement · Increased nature relatedness · Novelty enhancement · Thought connectivity · Creativity enhancement · Memory suppression · Thought acceleration · Cognitive impairment · Confusion · Focus suppression · Multiple thought streams · Thought disorganization · Analysis enhancement · Humor enhancement · Information processing enhancement · Cognitive fatigue · Information processing suppression · Memory fragmentation · Memory replays · Synchronicity · Thought loops
Simultaneous emotions · Anxiety · Catharsis
Trust enhancement · Communication enhancement · Sociability enhancement · Depersonalization · Flow state · Boundary dissolution · Identity alteration · Ego dissolution
Flow state · Boundary dissolution · Identity alteration · Ego dissolution
Time cessation
Transpersonal visions · Non-dual awareness
Recursive awareness
Timeline
Initial nasal absorption produces mild stimulation and faint bodily awareness. First alerts may include subtle warmth or tingling at the administration site.
Rapid build of visual and somatic effects. Body vibrations emerge alongside color enhancement and early geometric patterning. Stimulation intensifies.
Full visual hallucinogenesis with detailed geometric patterns and color enhancement. Body high and vibrations reach maximum. Characteristic cognitive clarity persists — analytical capacity maintained alongside pronounced perceptual effects.
Gradual reduction of visual effects and body sensations. Cognitive clarity persists as perceptual intensity diminishes. Mild stimulation and residual body awareness continue.
Residual stimulation and mild mood elevation. Possible physical fatigue as stimulation subsides. Subtle perceptual shifts may linger.
Safety[edit]
- Acute toxicity
- Low
- Chronic toxicity
- Low
- Withdrawal
- None
- Tolerance buildup
- rapid
- Tolerance reset
- 7 days
- Physical
- None
- Psychological
- Low
- Compulsive redosing
- Low
- Dose escalation
- Low
- Cross-tol.
- LSD · psilo · DMT
Toxicity
No controlled toxicology studies exist for EPT. Its lethal dose has not been determined in any species, and the therapeutic index is unknown.safety citation needed One death has been documented in which EPT or a metabolite was suspected as a contributing factor, but causal involvement was not established.[7]
Classical serotonergic psychedelics are generally considered to have low acute physical toxicity.[20][21] Morbidity from novel tryptamines is likely underestimated — polydrug contexts and behavioral risks during intoxication are common pathways to harm.[20] Psychedelic-related deaths are rare but do occur, and cardiovascular effects including vasoconstriction and increased heart rate are documented for the tryptamine class but not measured for EPT.[22]inferred
Psychological risks
The primary risks of EPT are psychological. Higher doses amplify the risk of thought loops, paranoia, ego dissolution, and overwhelming anxiety.[4]
Psychological state strongly shapes the experience — user reports identify set and setting as primary determinants of outcome.[4] No data exist on EPT and persisting perceptual changes, psychosis precipitation, or psychiatric destabilization. By class analogy, individuals with a personal or family history of psychotic spectrum disorders face elevated risk.inferred
Tolerance and dependence
Serotonin downregulation occurs rapidly with repeated use,[23] producing cross-tolerance to other serotonergic psychedelics. Community estimates place tolerance onset immediately after use, with a 3-day half-life and full reset around 7 days[2] — these are class-level estimates, not EPT-specific measurements.
Classical serotonergic psychedelics have low abuse potential and low abuse liability.[6] They do not produce physical dependence or withdrawal syndromes. Tryptamine hallucinogens develop somewhat less tolerance than phenethylamine hallucinogens in animal models.[24]
Drug interactions
No interaction data specific to EPT exist. All assessments below are inferred from tryptamine class pharmacology.
MAO inhibitors
This is the highest-risk interaction. MAO-A is EPT's presumed primary metabolic pathway — blocking it with a monoamine oxidase inhibitor dramatically increases tryptamine concentrations in the brain and body. Fatalities, severe agitation, and muscle breakdown have been documented for MAOI combinations with related tryptamines.[8] Combining EPT with any MAO inhibitor — pharmaceutical (phenelzine, tranylcypromine, moclobemide) or botanical (ayahuasca, Syrian rue) — represents a potentially life-threatening interaction.safety citation needed
SSRIs and SNRIs
Chronic SSRI or SNRI use may blunt EPT's effects through serotonin receptor downregulation.[25] Acute combined use raises theoretical risk of serotonin syndrome — a potentially life-threatening overheating and seizure response — though this risk is generally lower for tryptamines than for phenethylamines.[25]
Lithium
Lithium combined with serotonergic psychedelics has been associated with seizure risk.safety citation needed
Stimulants
Combining EPT with amphetamines or cocaine increases cardiovascular strain through additive activation of the sympathetic nervous system.inferred
Cannabis
Cannabis commonly amplifies and extends psychedelic effects. One report described the EPT-cannabis combination as manageable,[5] but individual responses vary widely.
Contraindications
No substance-specific contraindication data exist for EPT — all contraindications are inferred from serotonergic psychedelic class pharmacology.inferred
Concurrent MAO inhibitor use, personal history of psychotic spectrum disorders, and lithium therapy represent the most serious concerns. Cardiovascular disease, bipolar disorder, severe anxiety disorders, concurrent SSRI/SNRI use, and pregnancy are additional risk factors. No reproductive toxicity data exist, making EPT contraindicated in pregnancy by default.
Harm Reduction[edit]
Forms & Identification
EPT is distributed as a powder through research chemical vendors, typically as a hydrochloride or fumarate salt. All available material originates from unregulated synthesis with no quality guarantees.
Reagent testing cannot positively identify EPT but can exclude some dangerous substitutions. EPT has been found alongside 4-hydroxy-EPT and other tryptamine analogs in seized products,[3] making batch testing essential. Laboratory testing services provide the most reliable identification for novel tryptamines that lack established reagent color profiles.
Guidelines
- Test every batch with reagent kits before use. Novel tryptamines carry substitution and contamination risks.
- Start with a low dose and wait for full onset before considering redosing. Insufflated tryptamines can take 15–30 minutes to reach peak effects.
- Use a milligram-precision scale. Volumetric differences at the 40–80 mg range can meaningfully alter intensity.
- Have a sober, trusted person present — especially for first experiences with this compound.
- Prepare the physical space: comfortable temperature, accessible water, minimal sharp objects or fall hazards.
- Eat lightly beforehand. Avoid use on an empty stomach or immediately after a heavy meal.
Set & Setting
EPT's preserved cognitive clarity makes environmental factors unusually influential — anxiety and discomfort register sharply rather than dissolving into the altered state. A calm, familiar environment with minimal unexpected stimuli reduces the likelihood of difficult psychological responses.
Prior psychedelic experience is a meaningful protective factor. EPT's short duration makes it more manageable than longer-acting psychedelics, but the compressed timeline means intensity escalates quickly after onset.
Aftercare & integration. EPT's short duration means the return to baseline is relatively rapid, but processing the experience still matters — particularly after intense or difficult sessions. Allow several hours of unstructured time after the experience ends.
Write down impressions, images, and emotional responses within the first day while they remain accessible. Discussing the experience with a trusted person or integration-focused therapist can help contextualize unusual perceptions or difficult emotions. If anxiety, depersonalization, or perceptual disturbances persist beyond 48 hours, consult a mental health professional.
Recovery & Support
Classical serotonergic psychedelics carry low abuse liability, and compulsive use patterns are uncommon. If EPT use is becoming frequent, escalating in dose, or is being used to avoid confronting life circumstances, these patterns warrant honest self-assessment.
Peer support organizations such as the Fireside Project (psychedelic peer support line) and MAPS integration resources provide non-judgmental assistance. For patterns of problematic use, a therapist experienced with psychoactive substances is recommended.
Recovery resources, crisis lines, and support pathways → View all
Emergency Response
Recognizing an emergency: Uncomfortable anxiety and transient confusion during an EPT experience are distressing but not emergencies. Seek immediate help if a person shows signs of self-harm intent, complete dissociation from reality (unable to recognize surroundings or respond to their name), severe chest pain, seizure, or loss of consciousness.
Immediate steps:
- Stay with the person. Speak calmly and simply.
- Call emergency services if the person is unresponsive, seizing, experiencing chest pain, or expressing intent to harm themselves or others.
- If the person is unconscious but breathing, place them in the recovery position (on their side, airway clear).
- Do not restrain unless they are in immediate physical danger.
- Do not induce vomiting.
What to tell the dispatcher: Name the substance (EPT, a tryptamine psychedelic), the amount taken if known, the time of ingestion, and current symptoms. Good Samaritan laws in many jurisdictions protect people who call for help during a drug emergency.
No reversal agent exists for tryptamine psychedelics.
Legal Status[edit]
EPT occupies a varied legal position across jurisdictions — absent from international scheduling conventions, its status ranges from explicitly controlled to unscheduled but potentially prosecutable under structural analog laws.[26][2]
| Jurisdiction | Classification | Key provisions |
|---|---|---|
| United States | Unscheduled (federal) | Not specifically listed under the Controlled Substances Act. May be prosecutable under the Federal Analogue Act (21 U.S.C. §813) as a substance substantially similar to DMT (Schedule I) when intended for human consumption[26] |
| United Kingdom | Class A (Misuse of Drugs Act 1971) | Controlled under the tryptamine catch-all clause. Additionally illegal to sell, supply, or trade under the Psychoactive Substances Act 2016[26] |
| Germany | Controlled (NpSG) | Controlled under the Neue-psychoaktive-Stoffe-Gesetz as of July 18, 2019. Production, import, administration to another, and trading are punishable; possession is not separately penalized[26] |
| Canada | Not scheduled | Not listed under the Controlled Drugs and Substances Act as of 2025[26] |
| Japan | Status unconfirmed | EPT identified in seized products (2017–2019).[3] Explicit designated status could not be confirmed in available sources |
| Australia | Status unconfirmed | Specific scheduling status not confirmed. May be covered under TGA scheduling of tryptamine derivatives or state-level legislationcitation needed |
Analog act considerations
In the United States, the Federal Analogue Act extends Schedule I controls to substances structurally similar to listed compounds when intended for human consumption. EPT's structural relationship to DMT — differing only in the nitrogen substituents — establishes a plausible basis for prosecution. Application is determined case-by-case based on judicial interpretation of substantial similarity.
Legal status changes frequently and varies by jurisdiction. This information reflects available sources as of the article's last review and is not legal advice.
references
- [1] ^abFantegrossi WE, Reissig CJ, Katz EB, Yarosh HL, Rice KC, Winter JC (2008) Hallucinogen-like effects of N,N-dipropyltryptamine (DPT): possible mediation by serotonin 5-HT1A and 5-HT2A receptors in rodents. — Pharmacology, biochemistry, and behavior PMID:17905422
- [2]
- [3] ^abcdTanaka R, Kawamura M, Hakamatsuka T, Kikura-Hanajiri R (2020) Identification of six tryptamine derivatives as designer drugs in illegal products — Forensic Toxicology doi:10.1007/s11419-020-00556-5
- [4]
- [5]
- [6] ^abcReiche S, Hermle L, Gutwinski S, Jungaberle H, Gasser P, Majić T (2018) Serotonergic hallucinogens in the treatment of anxiety and depression in patients suffering from a life-threatening disease: A systematic review. — Progress in neuro-psychopharmacology & biological psychiatry doi:10.1016/j.pnpbp.2017.09.012