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DOPR
2,5-dimethoxy-4-propylamphetamine
DOPR (2,5-dimethoxy-4-propylamphetamine) is a synthetic psychedelic of the phenethylamine class. It is the most potent member of the DOx amphetamine series at serotonin receptors.[1] It activates serotonin receptors in the brain, producing the visual and cognitive shifts characteristic of classical psychedelics.
DOPR (2,5-dimethoxy-4-propylamphetamine) is a synthetic psychedelic of the phenethylamine class. It is the most potent member of the DOx amphetamine series by 5-HT₂A receptor activity.[1] DOPR is a full agonist at 5-HT₂A receptors, producing its effects by disrupting serotonin-mediated sensory gating in the prefrontal cortex.
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Alexander Shulgin first synthesized and documented DOPR around 1970, publishing the only human bioassay data in his 1991 book PiHKAL.[2] The compound remained virtually unknown for over three decades. Research interest revived in 2025 when animal studies found that low doses can enhance motivated effort — and DOPR remains unscheduled internationally.
Subjective effects include geometric visual patterns, closed-eye imagery, time alteration, and altered thinking. The experience is slow-building and extraordinarily persistent — a dream-adjacent, liminal quality between wakefulness and sleep that spans an entire day-night cycle. Insomnia extending well beyond the active period, physical restlessness, and prolonged psychological vulnerability are characteristic unsought effects.
DOPR does not produce physical dependence, and no lethal dose has been established[3] — but its extraordinary duration compounds physiological stress across a full day-night cycle. Class-level evidence links DOx compounds to dangerous agitation, seizures, and muscle breakdown.[4] All human data come from a single researcher's uncontrolled self-experiments; no formal toxicological or pharmacokinetic studies exist.
History[edit]
Discovery
DOPR was first synthesized by Alexander Shulgin around 1970,[5][6] part of his systematic work on 2,5-dimethoxyamphetamines. The first co-authored paper on related propyl analogs appeared in 1977.[7] His 1991 book PiHKAL provided the only published human data — dose, duration, and qualitative effects — as entry #71.[2]
Scientific significance
DOPR remained obscure for decades while DOI, DOB, and DOC attracted broader scientific attention. Modern studies eventually confirmed it as the most potent 4-alkyl DOx compound at serotonin receptors.[1]
Modern research
In 2025, Noback et al. found that sub-psychedelic doses enhance effortful motivation in mice — separating that effect from hallucination by roughly tenfold.[8] No clinical trials have been registered as of 2026.[8]
The name DOPR follows Shulgin's DOx convention: DO for 2,5-dimethoxyamphetamine, PR for the n-propyl substituent. Unlike DOM (known as "STP" in 1960s counterculture) or DOB, DOPR never acquired street names or cultural identity — it remained too rare to reach anyone beyond Shulgin's immediate circle.
Chemistry[edit]
Structural class
DOPR belongs to the DOx series — 2,5-dimethoxy-4-substituted amphetamines — a family of phenethylamine psychedelics. Its molecular formula is C₁₄H₂₃NO₂ (molecular weight 237.34 g/mol), and the hydrochloride salt melts at 182.5–183°C.[2] The alpha-methyl group on the side chain — absent in the related 2C-X phenethylamines — makes the molecule resistant to enzymatic breakdown, contributing to the class's characteristically long duration.[9]
Molecular properties
DOPR's 4-position substituent is an n-propyl chain — the optimal length for psychedelic potency in the DOx series. Activity drops sharply when the chain extends to butyl or longer.[10] Foundational work by Nichols, Shulgin, and Dyer established that the directional lipophilicity of the 4-substituent drives potency,[7] a relationship confirmed in modern binding studies.[11][12]
Pharmacology[edit]
Mechanism of action
DOPR is a potent full agonist at serotonin receptors — the primary targets producing its psychedelic effects.[1][6] DOx amphetamines produce stronger serotonin receptor activation than the related 2C-X phenethylamines, a difference attributed to the alpha-methyl group on the side chain.[9]
Pharmacokinetics
Only oral administration has been documented. Effects begin roughly 90 minutes after ingestion[2] and last 20–30 hours — far longer than LSD (~12 hours) or psilocybin (~6 hours).[2]
Three factors explain this extreme duration: the propyl group keeps the molecule in tissues longer, the alpha-methyl group resists enzymatic breakdown, and DOx agonists occupy serotonin receptors for a prolonged time.[6] DOx compounds are metabolized primarily at the methoxy positions;[3] all other pharmacokinetic parameters remain uncharacterized in humans. citation needed
Neuroscience[edit]
Where it acts
No neuroimaging data exist for DOPR. Based on its mechanism — potent serotonin receptor activation — it disrupts sensory gating in the prefrontal cortex, where these receptors cluster on specific neurons.[13] Studies of related psychedelics show this reduces the brain's default internal network and broadens associative connections.
DOPR also shifts production of BDNF — a molecule involved in brain growth and adaptation — decreasing it in memory circuits while increasing it in cortical areas.[14]
Why it matters
DOPR's 20+ hour duration raises a genuine open question: does sustained serotonin receptor activation over that span produce brain dynamics qualitatively different from shorter-acting psychedelics? Its demonstrated motivational effects at sub-hallucinogenic doses[8] also challenge all-or-nothing models of serotonin function and align with the idea that these compounds promote structural brain changes via growth factor signaling.[13][15]
- Does sustained serotonin receptor activation over 20+ hours produce desensitization patterns distinct from shorter-acting psychedelics?
- What dose threshold separates DOPR's motivational effects from its hallucinogenic effects?
- Does DOPR promote structural brain changes — new dendritic connections — as its neurotrophin profile suggests?
Subjective Effects[edit]
DOPR builds slowly and holds for an entire day-night cycle. At threshold, the experience has a liminal, dream-adjacent character — hovering between wakefulness and sleep.[2] Higher doses bring forceful, unavoidable visual distortion that cannot be set aside.
Within the DOx class, DOPR is more potent weight-for-weight than DOM and runs longer. Its alkyl substituent gives it a qualitative character closer to the methyl and ethyl homologues than to the halogenated compounds DOC and DOB. All experiential data derive from Shulgin's self-bioassays.
First documented by Alexander Shulgin in PiHKAL (1991) as part of his systematic exploration of 4-substituted 2,5-dimethoxyamphetamines,[2] DOPR remained virtually unknown for over three decades. Interest revived in 2025 when animal research demonstrated that sub-psychedelic doses enhance effortful motivation — separating motivational from hallucinogenic effects by roughly tenfold.[3] No clinical trials have been initiated, and DOPR remains unscheduled at the international level.
Subjective effects include geometric visual patterns, closed-eye imagery, time alteration, and thought alteration.[2] The experience builds slowly over roughly ninety minutes and settles into a sustained, dream-adjacent state dominated by visual phenomena that intensify with dose — a liminal quality between wakefulness and sleep characterizes threshold responses. Insomnia extending well beyond the active period, physical restlessness, and prolonged psychological vulnerability are characteristic unsought effects.
No physical dependence has been documented for DOPR or any DOx compound;[4] tolerance develops rapidly via downregulation,[5] and no lethal dose has been established in any species. The primary risk is duration — sustained cardiovascular stimulation, sleep deprivation, and psychological exposure over a full day-night cycle compound cumulative physiological stress, with class-level evidence indicating risk of dangerous agitation, seizures, and muscle breakdown.[6] All human data derive from a single researcher's uncontrolled self-bioassays; formal pharmacokinetic, toxicological, and dose-response data do not exist.
History[edit]
Discovery
DOPR was first documented by Alexander Shulgin, who synthesized it as part of his systematic exploration of 4-substituted 2,5-dimethoxyamphetamines. Secondary sources place the initial characterization around 1970,[7][8] though the earliest verifiable co-authored paper on DOx propyl analogs appeared in 1977.[9] Shulgin's 1991 book PiHKAL: A Chemical Love Story provided the only published human bioassay data — dose range, duration, and qualitative effect descriptions — as entry #71.[2]
Scientific significance
Within the DOx class, DOPR occupied a marginal position for decades. While DOI became a standard radioligand and DOB and DOC gained broader recognition, DOPR remained known primarily to PiHKAL readers and specialist chemists. Its pharmacological significance was established only retrospectively — first by foundational work on directional lipophilicity in 1977,[9] then by modern studies confirming it as the most potent 4-alkyl DOx homolog at 5-HT₂A receptors.[1]
Modern research
DOPR's research revival began in 2025, when Noback et al. demonstrated that sub-psychedelic doses enhance effortful motivation in mice — separating pro-motivational from hallucinogenic effects by approximately tenfold.[3] Luethi et al. (2026) subsequently confirmed its position as the in vitro 5-HT₂A potency leader among DOx 4-alkyl homologues.[1] No clinical trials have been registered as of 2026.[3]
The name DOPR follows Shulgin's systematic DOx naming convention: DO for 2,5-dimethoxy-amphetamine, PR for the n-propyl substituent at the 4-position. Unlike DOM (known as "STP" in 1960s counterculture) or DOB, DOPR never acquired street names or cultural identity — a consequence of its extreme rarity outside Shulgin's immediate circle and the specialist literature.
Chemistry[edit]
Structural class
DOPR belongs to the DOx series — 2,5-dimethoxy-4-substituted amphetamines — a family of phenethylamine psychedelics. The molecule carries methoxy groups at the 2- and 5-positions of the phenyl ring, an n-propyl chain at the 4-position, and an alpha-methyl group on the aminoethyl side chain.
The alpha-methyl group distinguishes DOx amphetamines from their 2C-X phenethylamine counterparts and confers resistance to monoamine oxidase breakdown, contributing to the class's characteristically long durations.[10] DOPR is positioned between DOET (4-ethyl) and the longer-chain homologues in the DOx structural lineage.
Molecular properties
| Molecular formula | C₁₄H₂₃NO₂ |
| Molecular weight | 237.34 g/mol |
The hydrochloride salt has a melting point of 182.5–183°C.[2] No published data on solubility or storage stability have been identified.
Stereochemistry
The alpha-methyl group creates one chirality center, yielding (R)- and (S)-enantiomers. Available DOPR is the racemic mixture.[11] Within the DOx class, the (R)-enantiomer generally shows higher activity at 5-HT₂A receptors,[10] but no DOPR-specific enantioselectivity studies have been published.
Structure-activity relationships
DOPR sits at a critical inflection point in DOx structure-activity work. The n-propyl chain represents the optimal 4-alkyl length for psychedelic potency — activity drops sharply with longer or branched substituents.[12] Foundational work by Nichols, Shulgin, and Dyer (1977) established that directional lipophilicity of the 4-substituent drives potency in the series.[9]
Subsequent research confirmed that lipophilic 4-position substituents generally enhance 5-HT₂A affinity.[13][14] The propyl group achieves the right balance between sufficient lipophilicity for strong receptor binding and appropriate molecular geometry for optimal engagement — a balance lost when the chain extends to butyl or amyl.
Pharmacology[edit]
Mechanism of action
DOPR is a potent full agonist at serotonin 5-HT₂A and 5-HT₂C receptors — the principal targets mediating its psychedelic effects.[1][8] It shows negligible activity at 5-HT₁ receptor subtypes, and its potency at 5-HT₂B receptors is reported as more than 25-fold lower than at 5-HT₂A.[8]
Receptor activation triggers a signaling cascade through Gq/G₁₁ proteins, driving calcium release inside cells. DOx amphetamines produce higher intrinsic activity at 5-HT₂A than their 2C-X phenethylamine counterparts — a distinction attributed to the alpha-methyl group on the side chain.[10]
Downstream of acute activation, DOx-class agonists regulate BDNF (BDNF) expression in a region-specific pattern: decreased in hippocampal circuits and increased in cortical areas. Both effects are blocked by the selective 5-HT₂A antagonist ketanserin, confirming receptor specificity.[15]
Pharmacokinetics
No human pharmacokinetic studies exist for DOPR. All characterization below is inferred from class-level data on structurally related DOx compounds.
Oral administration is the only documented route. Onset is slow, with threshold effects appearing approximately 90 minutes after ingestion.[2] Duration extends to 20–30 hours — exceptionally long for a serotonergic psychedelic and substantially longer than LSD (approximately 12 hours) or psilocybin (approximately 6 hours).[2]
Three pharmacological factors likely explain this extreme duration: high lipophilicity from the propyl substituent favoring sustained tissue distribution; the alpha-methyl group retarding enzymatic breakdown; and prolonged receptor occupancy characteristic of DOx agonists.[8]
Rodent data indicate that DOPR achieves the highest brain-to-plasma ratio among DOx 4-alkyl homologues, suggesting favorable blood-brain barrier penetration.[8] citation needed DOx compounds are metabolized primarily via O-demethylation at the 2- and 5-methoxy positions.[4] Peak plasma concentration, half-life, bioavailability, and metabolite identification remain entirely uncharacterized in humans.
Neuroscience[edit]
Where it acts
No direct neuroimaging or electrophysiology data exist for DOPR. Its mechanism — potent 5-HT₂A full agonism — places it among compounds that disrupt thalamocortical gating in the prefrontal cortex, where 5-HT₂A receptors are concentrated on layer V pyramidal neurons.[16] In studies of related psychedelics, this disruption reduces default mode network integrity and increases global neural connectivity — patterns linked to ego dissolution and expanded associative thinking.
DOPR also modulates BDNF expression in a region-specific pattern: suppression in hippocampal circuits and enhancement in cortical areas.[15] This bidirectional regulation may relate to the dual quality of psychedelic states — disruption of habitual processing alongside novel cognitive openness.
Why it matters
Two features make DOPR theoretically interesting. Its extreme duration raises the question of whether sustained 5-HT₂A activation produces qualitatively different brain dynamics than shorter-acting psychedelics — an untested hypothesis with implications for the REBUS (Relaxed Beliefs Under Psychedelics) model of psychedelic action.
Separately, DOPR's demonstrated pro-motivational effects at sub-psychedelic doses[3] suggest that low-level 5-HT₂A activation can modulate effort-based decision-making without full perceptual disruption. This tenfold dose separation between motivation and hallucination challenges all-or-nothing models of 5-HT₂A function and aligns with the psychoplastogen hypothesis — that these compounds promote structural brain changes via neurotrophin signaling.[16][17]
- Does sustained 5-HT₂A activation over 20+ hours produce receptor desensitization dynamics distinct from shorter-acting agonists?
- What receptor occupancy threshold separates DOPR's motivational effects from its psychedelic effects?
- Does DOPR promote structural neuroplasticity — dendritic branching and spine growth — as its neurotrophin profile suggests?
Subjective Effects[edit]
DOPR produces a slow-building psychedelic experience defined by its extraordinary persistence. At threshold doses, a liminal, dream-adjacent quality dominates — hovering between wakefulness and sleep. As dose increases, visual phenomena intensify from subtle closed-eye imagery to forceful, unavoidable perceptual distortion.[2] Set and setting exert substantial influence across the full dose range, and the multi-day window means environmental planning extends well beyond the immediate session.
Within the DOx class, DOPR is distinguished from DOM by greater weight-for-weight potency and longer duration. Its alkyl (rather than halogen) 4-substituent gives it a qualitative character more closely aligned with the methyl and ethyl homologues than with the halogenated compounds DOC and DOB. All experiential data derive from Shulgin's uncontrolled self-bioassays.
Effect Grid
Prominent visual effects define the experience — visual drifting, geometry, and color enhancement are clearly present. Environmental patterning and visual breathing become noticeable. Internal hallucinations gain complexity. Significant cognitive alteration includes thought connectivity, conceptual thinking, and introspection enhancement.
Emotional enhancement and time alteration are pronounced. Stimulation and wakefulness are sustained. Muscle tension, vasoconstriction, and appetite suppression are common physical accompaniments. Pupil dilation is reliable. Nausea is possible during the come-up.
Insomnia is likely for the full duration of 20–28 hours. This is a full psychedelic experience requiring a complete day-night cycle of commitment. Do not plan obligations for the following day.
Modeled from the effect's dose-dependence curve — not per-substance measurements.
Brightness alteration · Color alteration · Depth perception distortion · Environmental patterning · Music enhancement · Symmetrical texture repetition · Tracers · Visual breathing · After-images · Auditory enhancement · Light sensitivity · Peripheral vision distortion · Perspective distortion · Proprioceptive distortion · Sound sensitivity · Touch enhancement · Visual diffraction · Holotropic state · Visual magnification · Visual melting · Visual haze / noise · Auditory distortion · Auditory misinterpretation · Peripheral misidentification · Spatial disorientation · Vestibular distortion · Visual acuity enhancement · Synesthesia · Visual processing acceleration · Flashbacks · Object transformations · Environmental orbism / cubism · External hallucinations · Object activation · Internal hallucinations · Perspective hallucinations · Visual flipping · Visual recursion · Visual scenery slicing · Auditory hallucinations · Persisting hallucinations
Music enhancement · Symmetrical texture repetition · Tracers · Visual breathing · After-images · Auditory enhancement · Light sensitivity · Peripheral vision distortion · Perspective distortion · Proprioceptive distortion · Sound sensitivity · Touch enhancement · Visual diffraction · Holotropic state · Visual magnification · Visual melting · Visual haze / noise · Auditory distortion · Auditory misinterpretation · Peripheral misidentification · Spatial disorientation · Vestibular distortion · Visual acuity enhancement · Synesthesia · Visual processing acceleration · Flashbacks · Object transformations · Environmental orbism / cubism · External hallucinations · Object activation · Internal hallucinations · Perspective hallucinations · Visual flipping · Visual recursion · Visual scenery slicing · Auditory hallucinations · Persisting hallucinations
Appetite suppression · Body high · Heart rate perception changes · Muscle tension · Physical fatigue · Spontaneous body sensations · Bodily pressures · Dehydration sensation · Dry mouth · Excessive sweating · Nausea · Restlessness · Tingling / electric sensations · Body schema distortion · Bruxism · Dizziness · Tactile euphoria · Vibrations / buzzing · Bodily lightness · Breathing alteration · Headache · Laughter fits · Respiratory stimulation · Sexual arousal enhancement · Trembling · Involuntary body movements · Nystagmus (eye wobbles) · Vomiting · Tactile hallucination
Physical fatigue · Spontaneous body sensations · Bodily pressures · Dehydration sensation · Dry mouth · Excessive sweating · Nausea · Restlessness · Tingling / electric sensations · Body schema distortion · Bruxism · Dizziness · Tactile euphoria · Vibrations / buzzing · Bodily lightness · Breathing alteration · Headache · Laughter fits · Respiratory stimulation · Sexual arousal enhancement · Trembling · Involuntary body movements · Nystagmus (eye wobbles) · Vomiting · Tactile hallucination
Cognitive flexibility · Conceptual thinking · Immersion enhancement · Introspection enhancement · Novelty enhancement · Openness enhancement · Pattern recognition enhancement · Thought acceleration · Thought connectivity · Thought loops · Creativity enhancement · Increased nature relatedness · Multiple thought streams · Analysis enhancement · Cognitive dysphoria · Cognitive impairment · Confusion · Focus enhancement · Information processing enhancement · Memory fragmentation · Motivation enhancement · Synchronicity · Thought disorganization · Humor enhancement · Delusions of sobriety
Introspection enhancement · Novelty enhancement · Openness enhancement · Pattern recognition enhancement · Thought acceleration · Thought connectivity · Thought loops · Creativity enhancement · Increased nature relatedness · Multiple thought streams · Analysis enhancement · Cognitive dysphoria · Cognitive impairment · Confusion · Focus enhancement · Information processing enhancement · Memory fragmentation · Motivation enhancement · Synchronicity · Thought disorganization · Humor enhancement
Simultaneous emotions · Anxiety · Empathy enhancement · Anhedonia · Catharsis · Irritability · Dysphoria
Catharsis · Irritability · Dysphoria
Disinhibition · Social connection · Trust enhancement · Ego inflation · Sociability enhancement · Communication enhancement · Flow state · Boundary dissolution · Identity alteration · Cognitive disconnection · Ego dissolution · Telepathic feelings
Sociability enhancement · Communication enhancement · Flow state · Boundary dissolution · Identity alteration · Cognitive disconnection · Ego dissolution · Telepathic feelings
Time cessation
Entity contact · Non-dual awareness · Death-rebirth sequence
Timeline
Subtle threshold awareness develops very gradually. A faint shift in cognitive texture and mild perceptual sharpening emerge over 60–120 minutes. Physical cues are minimal — slight alertness, possible mild stomach awareness.
Slow, steady build of perceptual and cognitive effects over 2–4 hours. Color enhancement, early geometry, and emerging thought connectivity. Stimulation and wakefulness increase.
Full psychedelic effects — prominent visual drifting, geometry, and color enhancement. Deep cognitive alteration with introspection enhancement and time alteration. Emotional intensity is high.
Gradual reduction in intensity over 6–12 hours, but effects remain clearly present. Visual phenomena diminish before cognitive effects. Stimulation and wakefulness persist.
Residual cognitive shifts, mild perceptual sensitivity, and emotional openness may linger for 12–24 hours. Insomnia may persist beyond the subjective experience. Baseline may not fully return until sleep is achieved.
Safety[edit]
- Acute toxicity
- Moderate
- Chronic toxicity
- Low
- Withdrawal
- None
- Tolerance buildup
- rapid
- Tolerance reset
- 7 days
- Physical
- None
- Psychological
- Negligible
- Compulsive redosing
- Negligible
- Dose escalation
- Negligible
- Cross-tol.
- LSD · psilo · mesc
Toxicity
No lethal dose, controlled toxicity study, or adverse event report specific to DOPR has been published. The toxicological picture comes entirely from class-level evidence on related DOx compounds.
Acute toxicity
Based on class evidence from DOC, DOI, and DOB,[3][4] toxic presentations include agitation, prolonged hallucinations, rapid heart rate, dangerous overheating, seizures, and muscle breakdown. Symptoms may persist for up to 33 hours. safety citation needed
Heart and circulation
DOx compounds activate a receptor associated with heart valve damage under chronic use — a risk established by the fenfluramine precedent. DOPR's activity at this receptor is more than 25-fold lower than at its primary serotonin target,[6][12] reducing but not eliminating this concern for repeated use. safety citation needed
Duration as a risk factor
The 20–30-hour duration is itself a toxicity amplifier. Sustained cardiovascular stimulation, extreme sleep deprivation, and prolonged psychological exposure compound over a full day-night cycle — far exceeding the physiological stress of LSD (~12 hours) or psilocybin (~6 hours).
Psychological risks
No controlled data on DOPR-specific psychological adverse events exist.
Acute distress — anxiety, panic, and paranoid thinking — can occur at any dose. The extended duration increases the period of exposure and removes the reassurance that the experience will end soon.
Prolonged psychotic states have been reported with DOx use, particularly at high doses or with predisposing conditions.[3] Insomnia lasting into the following day — documented by Shulgin[2] — compounds cognitive impairment and psychosis risk. No DOPR-specific data on HPPD (HPPD — lingering visual disturbances after the experience ends) exist.
Tolerance and dependence
Tolerance
Tolerance to serotonergic psychedelics builds rapidly: serotonin receptors decrease in number and responsiveness with repeated activation.[16] Cross-tolerance is expected between DOPR and other serotonin-activating psychedelics — LSD, psilocybin, mescaline, and other DOx compounds.[17] Standard guidance suggests 3–5 days between sessions; DOPR's 20–30-hour duration makes longer intervals appropriate.
Dependence
No physical dependence or withdrawal has been documented for DOPR or any DOx compound.[3] Serotonergic psychedelics do not activate the reward systems that drive classic addiction.[13]
Drug Interactions
No DOPR-specific interaction data exist.
Serotonergic combinations
MAOIs block the enzymatic breakdown of DOx compounds, amplifying both intensity and duration. The combination risks serotonin syndrome — dangerous overheating, muscle rigidity, and cardiovascular collapse.[18] Absolute contraindication.
SSRIs/SNRIs may reduce DOPR's effects through downregulation. Serotonin syndrome risk is theoretically elevated but poorly characterized for DOx compounds specifically.
Other interactions
Stimulants: Combining DOPR with other amphetamines, MDMA, or cocaine compounds cardiovascular load — heart rate, blood pressure, and overheating risk are additive. safety citation needed
Lithium lowers seizure threshold and increases serotonin syndrome risk with serotonergic psychedelics as a class. Contraindicated. safety citation needed
mGlu₂/₃ agonists diminish behavioral responses to serotonin-activating phenethylamines with chronic use.[19]
Contraindications
7 knownNo DOPR-specific contraindication data exist. The following are inferred from the DOx class:
- Psychotic spectrum disorders: Serotonin receptor agonists may trigger or worsen psychotic episodes. Absolute contraindication.
- Bipolar disorder: Risk of manic episode. DOPR's extended duration compounds this through prolonged mood destabilization.
- Heart conditions: Sustained stimulant effects over 20–30 hours present elevated risk for individuals with cardiovascular disease.
- Seizure disorders: DOx-class toxicity includes seizure risk.
- Concurrent MAOI use: Absolute contraindication. Serotonin syndrome risk.
- Concurrent lithium use: Absolute contraindication. Seizure and serotonin syndrome risk.
- Pregnancy: No reproductive toxicity data exist. Serotonergic psychedelics are contraindicated in pregnancy as a class. safety citation needed
Harm Reduction[edit]
Forms & Identification
DOPR is exceptionally rare in unregulated markets. Most circulating material comes from research chemical suppliers selling the hydrochloride salt as an analytical reference standard.[20] This scarcity makes misidentification the primary supply-side risk — material sold as DOPR may contain DOB, DOC, or entirely different substances.
Reagent testing can confirm the presence of a phenethylamine but cannot distinguish individual DOx compounds. Quantitative analysis — GC-MS or FTIR through services like DrugsData or WEDINOS — is the only reliable way to confirm identity and purity. At milligram-level doses, even minor mislabeling can dramatically alter the experience.
Guidelines
- Test material with reagent kits and, if accessible, quantitative analytical services before use.
- Use an analytical balance (±0.1 mg) or volumetric dosing solution. Eyeballing milligram-range doses is not safe.
- Start at the lowest documented threshold (2.5 mg oral) for a first experience. Do not escalate during the same session.
- Prepare the physical space for a 24+ hour experience: food, water, blankets, temperature control, access to a bathroom.
- Arrange a sitter. Plan for sitter rotation — a single sitter cannot maintain attention for the full duration.
- Clear the following day's obligations entirely. Sleep will not come during the active period and may be disrupted afterward.
- Do not redose based on the slow onset. Wait at least three hours before concluding that threshold effects are absent.
Set & Setting
DOPR's 20–30-hour duration demands environmental planning on a different scale than most psychedelics. The session spans an entire day-night cycle; the setting must remain safe, comfortable, and accessible throughout — food, hydration, temperature control, and eventual sleep all need preparation.
An experienced sitter who can rotate is strongly recommended. No single sitter can remain attentive for 24+ hours; planning for handoffs is practical. The slow onset — roughly 90 minutes — can tempt redosing before effects fully manifest, a dangerous pattern given the compound's potency and duration.
Aftercare & integration. The aftermath of a 20–30-hour experience is physically and psychologically demanding. Prioritize sleep — even if full sleep is difficult, rest in a dark, quiet environment. Rehydrate and eat light, easily digestible food.
Emotional processing may take days or weeks. Journaling within the first 48 hours can capture details that fade quickly. Intense or distressing experiences benefit from conversation with a trusted person or a psychedelic integration therapist. Do not make major life decisions in the days immediately following — cognitive and emotional baseline typically takes several days to restore after this duration class.
Recovery & Support
Serotonergic psychedelics like DOPR do not produce physical dependence or withdrawal. Compulsive use patterns are rare but not impossible — particularly when the substance is being used to manage underlying psychological distress. If use feels driven rather than chosen, or if experiences are consistently distressing but use continues, professional support is warranted. Psychedelic harm reduction services, peer support communities, and mental health professionals familiar with psychedelic use can provide appropriate guidance.
Recovery resources, crisis lines, and support pathways → View all
Emergency Response
Recognizing an emergency
Most DOPR experiences involve sustained discomfort that resolves without medical intervention. Seek immediate help if any of the following occur:
- Seizure or loss of consciousness
- Body temperature that feels dangerously hot to the touch
- Chest pain or irregular heartbeat
- Self-harm behavior or complete disconnection from reality
- Severe agitation that cannot be managed with verbal reassurance
Immediate steps
- Call emergency services. Do not wait to see if symptoms resolve — DOPR's duration means they may persist for many hours.
- Place an unconscious person in the recovery position (on their side, airway clear).
- Cool an overheating person with wet cloths, fans, or cool water. Do not use ice baths.
- Do not physically restrain an agitated person unless there is immediate danger of self-harm.
- Do not induce vomiting.
What to tell the dispatcher
State that the person has taken a long-acting psychedelic amphetamine, the approximate dose and 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 DOPR or any serotonergic psychedelic. Medical management is supportive: benzodiazepines for agitation, cooling for overheating, monitoring for cardiac complications.
Legal Status[edit]
DOPR is not scheduled under any United Nations drug convention.[3] National regulation varies — some jurisdictions apply explicit scheduling, others rely on structural analog provisions, and several have no specific classification.
Legal status changes frequently and varies by jurisdiction. The information below is not legal advice. Verify current status with a legal professional before purchase, possession, or use.
| Jurisdiction | Classification | Key provisions |
|---|---|---|
| United States | Not explicitly scheduled | Not named in the Controlled Substances Act. DOM (4-methyl analog) is Schedule I. May fall under the Federal Analogue Act if intended for human consumption. Available from chemical suppliers as an analytical reference standard.[20] |
| Canada | Schedule III (CDSA) | Controlled under broad phenethylamine blanket-ban language.[6] |
| United Kingdom | Covered by Psychoactive Substances Act 2016 | Prohibited under blanket psychoactive substance legislation. Chemical suppliers require a Home Office licence.[6] citation needed Specific Misuse of Drugs Act 1971 classification was not confirmed. |
| European Union | Not scheduled at EU level | Individual member states may apply national analogue laws or blanket bans. |
| Australia | Status unresolved | No specific scheduling identified. State-level analogue provisions may apply. citation needed |
| International (UN) | Not internationally scheduled | Not listed under the 1961, 1971, or 1988 United Nations conventions.[3] |
Analogue act considerations
DOPR's structural similarity to DOM (Schedule I in the United States) is the primary legal vulnerability. The Federal Analogue Act treats structural analogs of Schedule I or II substances as Schedule I when intended for human consumption. DOPR shares the 2,5-dimethoxyamphetamine scaffold with DOM and works through the same receptor mechanism.
Safety[edit]
- Acute toxicity
- Moderate
- Chronic toxicity
- Low
- Withdrawal
- None
- Tolerance buildup
- rapid
- Tolerance reset
- 7 days
- Physical
- None
- Psychological
- Negligible
- Compulsive redosing
- Negligible
- Dose escalation
- Negligible
- Cross-tol.
- LSD · psilo · mesc
Toxicity
No lethal dose, controlled toxicity study, or human adverse event report specific to DOPR has been published. The toxicological profile rests entirely on class-level evidence from structurally related DOx compounds.
Acute toxicity
Based on class evidence from DOC, DOI, and DOB,[4][6] DOx toxicity presentations include:
- Agitation and aggressive behavior
- Prolonged hallucinations
- Rapid heart rate
- Dangerous overheating
- Seizures
- Muscle breakdown (particularly in severe cases with agitation and overheating)
Symptoms may persist for up to 33 hours in DOx poisoning cases. safety citation needed
Heart and circulation
DOx compounds show correlated binding at 5-HT₂A and serotonin₂B receptors.[14] Chronic 5-HT₂B activation is linked to heart valve damage, as established by the fenfluramine precedent. DOPR's 5-HT₂B potency is more than 25-fold lower than its 5-HT₂A potency,[8] reducing but not eliminating this concern for repeated use. safety citation needed
Duration as a risk factor
The 20–30-hour duration is itself a toxicity amplifier. Sustained cardiovascular stimulation, extreme sleep deprivation, dehydration from prolonged sympathomimetic activation, and extended psychological vulnerability compound over a full day-night cycle — far exceeding the physiological stress of LSD (approximately 12 hours) or psilocybin (approximately 6 hours).
Psychological risks
No controlled data on DOPR-specific psychological adverse events exist. Class-level risks include:
- Acute distress: anxiety, panic, and paranoid thinking may occur at any dose, modulated by set, setting, and individual vulnerability. The extended duration increases the period of exposure and undermines the reassurance that "it will end soon."
- Psychotic episodes: Prolonged psychotic states have been reported with DOx compound use, particularly at high doses or in individuals with predisposing conditions.[4]
- Hallucinogen persisting perception disorder (HPPD): No DOPR-specific prevalence data exist. HPPD has been associated with serotonergic psychedelic use broadly.
- Sleep deprivation: insomnia lasting into the following day was documented by Shulgin.[2] Extended sleeplessness compounds cognitive impairment, emotional lability, and psychosis risk.
Tolerance and dependence
Tolerance
No DOPR-specific tolerance data exist. Class-level evidence shows rapid tolerance to serotonergic psychedelics via 5-HT₂A downregulation — chronic treatment in rats produces reduced receptor density and diminished responsiveness in prefrontal and cingulate cortex.[5]
Cross-tolerance is expected between DOPR and other 5-HT₂A agonists (LSD, psilocybin, mescaline, other DOx compounds).[18] Standard guidance suggests 3–5 days between psychedelic doses for tolerance to reset; given DOPR's 20–30-hour duration, longer intervals may be appropriate.
Dependence
No physical dependence or withdrawal has been documented for DOPR or the broader DOx class.[4] Serotonergic psychedelics do not produce classic reward-reinforcement patterns or withdrawal syndromes.[16]
Drug Interactions
No DOPR-specific interaction studies exist. All data below are class-level inferences.
Serotonergic combinations
MAOIs: Contraindicated. Monoamine oxidase inhibition blocks enzymatic breakdown of DOx compounds, potentially increasing both intensity and duration. The combination carries risk of serotonin syndrome — a life-threatening condition involving dangerous overheating, muscle rigidity, and cardiovascular instability.[19]
SSRIs/SNRIs: Chronic SSRI use may reduce DOPR's effects via receptor downregulation. Serotonin syndrome risk is theoretically elevated but poorly characterized for DOx compounds specifically.
Other interactions
Stimulants: DOPR is an amphetamine derivative. Combination with other stimulants (amphetamines, MDMA, cocaine) compounds cardiovascular load — rapid heart rate, high blood pressure, and overheating risk are additive. safety citation needed
Lithium: Contraindicated with serotonergic psychedelics as a class. Lithium lowers seizure threshold and increases serotonin syndrome risk. safety citation needed
mGlu₂/₃ agonists: Chronic treatment with these compounds diminishes behavioral responses to 5-HT₂A agonist phenethylamines.[20]
Contraindications
7 knownNo DOPR-specific contraindication data exist. The following are inferred from the DOx class:
- Psychotic spectrum disorders: 5-HT₂A agonists may trigger or worsen psychotic episodes. Absolute contraindication.
- Bipolar disorder: Risk of manic episode. DOPR's extended duration compounds this risk through prolonged mood destabilization.
- Heart conditions: Sustained sympathomimetic effects over 20–30 hours present risk for individuals with pre-existing cardiovascular disease.
- Seizure disorders: DOx-class toxicity includes seizure risk; individuals with lowered seizure threshold face elevated risk.
- Concurrent MAOI use: Absolute contraindication due to serotonin syndrome risk.
- Concurrent lithium use: Absolute contraindication due to seizure and serotonin syndrome risk.
- Pregnancy: No reproductive toxicity data exist. Serotonergic psychedelics are contraindicated in pregnancy as a class. safety citation needed
Harm Reduction[edit]
Forms & Identification
DOPR is exceptionally rare in unregulated markets — most circulating material originates from research chemical suppliers selling the hydrochloride salt as an analytical reference standard.[21] This scarcity makes misidentification and mislabeling the primary supply-side risk: material sold as DOPR could contain more common DOx compounds (DOB, DOC) or entirely different substances.
Reagent testing can confirm the presence of a phenethylamine but cannot distinguish between individual DOx homologues. Quantitative analysis (GC-MS or FTIR through services like DrugsData or WEDINOS) is the only reliable way to confirm identity and purity. Given the milligram-level active dose range, even small contamination or mislabeling errors can produce dramatically different effects.
Guidelines
- Test material with reagent kits and, if accessible, quantitative analytical services before use.
- Use an analytical balance (±0.1 mg) or volumetric dosing solution. Eyeballing milligram-range doses is not safe.
- Start at the lowest documented threshold (2.5 mg oral) for a first experience. Do not escalate during the same session.
- Prepare the physical space for a 24+ hour experience: food, water, blankets, temperature control, access to a bathroom.
- Arrange a sitter. Plan for sitter rotation — a single sitter cannot maintain attention for the full duration.
- Clear the following day's obligations entirely. Sleep will not come during the active period and may be disrupted afterward.
- Do not redose based on the slow onset. Wait at least three hours before concluding that threshold effects are absent.
Set & Setting
DOPR's 20–30-hour duration demands environmental planning on a different scale than most psychedelics. A session effectively spans an entire day-night cycle, and the setting must remain safe, comfortable, and accessible throughout — including provisions for food, hydration, temperature control, and eventual sleep.
An experienced sitter who can rotate or be relieved is strongly recommended. No sitter can realistically remain attentive for 24+ hours; planning for handoffs is practical, not excessive. The slow onset (approximately 90 minutes) can tempt redosing before effects fully manifest — a dangerous pattern given the compound's potency and duration.
Aftercare & integration. The aftermath of a 20–30-hour psychedelic experience is physically and psychologically demanding. Prioritize sleep — even if full sleep is difficult, rest in a dark, quiet environment. Rehydrate and eat light, easily digestible food.
Emotional processing may take days or weeks. Journaling within the first 48 hours can capture details that fade quickly. Intense or distressing experiences benefit from conversation with a trusted person or a psychedelic integration therapist. Do not make major life decisions in the days immediately following — cognitive and emotional baseline typically takes several days to restore after this duration class.
Recovery & Support
Serotonergic psychedelics like DOPR do not produce physical dependence or withdrawal. Compulsive use patterns are rare but not impossible — particularly if the substance is being used to manage underlying psychological distress. If use feels driven rather than chosen, or if experiences are consistently distressing but use continues, professional support is warranted. Psychedelic harm reduction services, peer support communities, and mental health professionals familiar with psychedelic use can provide appropriate guidance.
Recovery resources, crisis lines, and support pathways → View all
Emergency Response
Recognizing an emergency
Most DOPR experiences involve sustained discomfort that resolves without medical intervention. Seek immediate help if any of the following occur:
- Seizure or loss of consciousness
- Body temperature that feels dangerously hot to the touch
- Chest pain or irregular heartbeat
- Self-harm behavior or complete disconnection from reality
- Severe agitation that cannot be managed with verbal reassurance
Immediate steps
- Call emergency services. Do not wait to see if symptoms resolve — DOPR's duration means they may persist for many hours.
- Place an unconscious person in the recovery position (on their side, airway clear).
- Cool an overheating person with wet cloths, fans, or cool water. Do not use ice baths.
- Do not physically restrain an agitated person unless there is immediate danger of self-harm.
- Do not induce vomiting.
What to tell the dispatcher
State that the person has taken a long-acting psychedelic amphetamine, the approximate dose and 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 DOPR or any serotonergic psychedelic. Medical management is supportive: benzodiazepines for agitation, cooling for overheating, monitoring for cardiac complications.
Legal Status[edit]
DOPR is not scheduled under any United Nations drug convention.[4] National regulation varies, with some jurisdictions applying explicit scheduling, others relying on structural analog provisions, and several maintaining no specific classification.
| Jurisdiction | Classification | Key provisions |
|---|---|---|
| United States | Not explicitly scheduled | Not named in the Controlled Substances Act. DOM (4-methyl analog) is Schedule I. May fall under the Federal Analogue Act if intended for human consumption. Available from chemical suppliers as an analytical reference standard.[21] |
| Canada | Schedule III (CDSA) | Controlled under broad phenethylamine blanket-ban language.[8] |
| United Kingdom | Covered by Psychoactive Substances Act 2016 | Prohibited under blanket psychoactive substance legislation. Chemical suppliers require a Home Office licence.[8] citation needed Specific Misuse of Drugs Act 1971 classification was not confirmed. |
| European Union | Not scheduled at EU level | Individual member states may apply national analogue laws or blanket bans. |
| Australia | Status unresolved | No specific scheduling identified. State-level analogue provisions may apply. citation needed |
| International (UN) | Not internationally scheduled | Not listed under the 1961, 1971, or 1988 United Nations conventions.[4] |
Analogue act considerations
DOPR's structural relationship to DOM (Schedule I in the United States) is the primary legal vulnerability. The Federal Analogue Act treats structural analogs of Schedule I or II substances as Schedule I when intended for human consumption. DOPR shares the 2,5-dimethoxyamphetamine scaffold with DOM and produces psychedelic effects through the same receptor mechanism. Sale as an analytical reference standard or research chemical may fall outside this provision, though enforcement varies.
Frequently asked questions
How long does DOPR last?
Total duration by route of administration — Oral: 20 – 30 hours. Ranges vary with dose and individual factors; see the duration table for onset, peak, and after-effect phases.
Where can I find dosage information for DOPR?
Psychedex publishes a dosage table for DOPR on this page covering these routes of administration: oral. Dose values are presented only in that table, always alongside their route of administration.
What are dangerous combinations with DOPR?
The highest-severity documented interactions for DOPR: MAOIs (Lethal), Buspirone (Dangerous), Dopamine agonists (Dangerous), GHB, Baclofen (Dangerous), GHB, GBL (Dangerous). See the interactions section for the full list with mechanisms and severity levels.
Is DOPR addictive?
Psychedex records tolerance and dependence data rather than a yes/no rating. Recorded tolerance indicators for DOPR: tolerance builds rapid; full reset takes 7 days; cross-tolerance develops with LSD, psilocybin, mescaline, DOM, DOC, DOB, DOI, DOET, 2C-P, 2C-B. See the article's dependence and safety sections for recorded dependence data.
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references
- [1] ^abcLuethi D et al. (2026) The 4-alkyl chain length of 2,5-dimethoxyamphetamines differentially affects in vitro serotonin receptor actions versus in vivo psychedelic-like effects — Molecular Psychiatry doi:10.1038/s41380-025-03325-1
- [2]
- [3]
- [4] ^abHalberstadt AL (2017) Pharmacology and Toxicology of N-Benzylphenethylamine (NBOMe) Hallucinogens — Current Topics in Behavioral Neurosciences doi:10.1007/7854_2016_64
- [5]
- [6]
references
- [1] ^abcdLuethi D et al. (2026) The 4-alkyl chain length of 2,5-dimethoxyamphetamines differentially affects in vitro serotonin receptor actions versus in vivo psychedelic-like effects — Molecular Psychiatry doi:10.1038/s41380-025-03325-1
- [2]
- [3] ^abcdNoback M, Kenton JA, Klein AK, Hughes ZA, Kruegel AC, Schmid Y, Halberstadt AL, Young JW (2025) Low (micro)doses of 2,5-dimethoxy-4-propylamphetamine (DOPR) increase effortful motivation in low-performing mice — Neuropharmacology doi:10.1016/j.neuropharm.2025.110334
- [4]
- [5] ^abGresch PJ, Smith RL, Barrett RJ, Sanders-Bush E (2005) Behavioral tolerance to lysergic acid diethylamide is associated with reduced serotonin-2A receptor signaling in rat cortex — Neuropsychopharmacology doi:10.1038/sj.npp.1300711
- [6] ^abHalberstadt AL (2017) Pharmacology and Toxicology of N-Benzylphenethylamine (NBOMe) Hallucinogens — Current Topics in Behavioral Neurosciences doi:10.1007/7854_2016_64