Psychedex is in open beta. We are still fine-tuning the generation and review process. Please double-check sources.
+1 more
Serotonin receptor ligandpsilocybin, psilocin, LSD +5 morepsilocybin, psilocin, LSD, mescaline, DMT, 4-AcO-DMT, 4-HO-MET, 4-AcO-DET show less
4-HO-DET
4-hydroxy-N,N-diethyltryptamine
4-HO-DET (4-hydroxy-N,N-diethyltryptamine) — also known as CZ-74 — is a synthetic psychedelic of the tryptamine class. It is the diethyl counterpart of psilocin, the active compound in psilocybin mushrooms. It activates serotonin receptors in the brain, producing the visual and cognitive shifts characteristic of classical psychedelics.
4-HO-DET (4-hydroxy-N,N-diethyltryptamine) — also known as CZ-74 — is a synthetic psychedelic of the tryptamine class. It is the N,N-diethyl homolog of psilocin, with comparable potency and a moderately shorter duration. 4-HO-DET is a presumed 5-HT₂A receptor agonist, producing its effects by disrupting serotonergic filtering of sensory and cognitive input.[1]
Psychedex is in open beta. We are still fine-tuning the generation and review process. Please double-check sources.
+1 more
Serotonin receptor ligandpsilocybin, psilocin, LSD +5 morepsilocybin, psilocin, LSD, mescaline, DMT, 4-AcO-DMT, 4-HO-MET, 4-AcO-DET show less
Albert Hofmann and Franz Troxler synthesized it at Sandoz Pharmaceuticals in the late 1950s.[1] Hanscarl Leuner conducted over 160 psycholytic therapy sessions with it in 1960s Germany, valuing its shorter duration compared to LSD.[2] Clinical use ended with prohibition in the early 1970s; it now circulates in small quantities on research chemical markets.
Subjective effects include geometric visual patterns, emotional intensification, time alteration, and shifts in thought.[3] The experience is close to psilocin — warm, moderately paced, and emotionally saturating — with reports of a slightly lighter physical sensation.[4] Nausea, body tremors, and jaw tension are common unwanted effects.[5]
4-HO-DET does not produce physical dependence, and rapid tolerance limits compulsive use.[6][7] The primary risks are psychological — panic, paranoia, and psychosis in predisposed individuals — and combining it with MAOIs or tramadol risks dangerous overheating and seizures. No controlled safety data exist; what is known comes from Shulgin's personal bioassays and Leuner's unpublished clinical observations.[5]
History[edit]
Discovery
4-HO-DET was synthesized by Albert Hofmann and Franz Troxler at Sandoz Pharmaceuticals in Basel in the late 1950s, designated internally as CZ-74.[1] It emerged from Sandoz's systematic exploration of psychoactive tryptamines following Hofmann's isolation of psilocybin in 1958.[8] A phosphate ester prodrug — ethocybin (CEY-19) — was developed alongside it, mirroring the psilocybin-to-psilocin relationship.
Clinical significance
Hanscarl Leuner conducted more than 160 psycholytic therapy sessions using CZ-74 in 1960s Germany.[2][5] He valued it over LSD primarily for its shorter duration, which fit within a standard clinical workday. His unpublished German-language records remain the largest body of human clinical data for the compound.
Prohibition and modern use
International prohibition ended clinical use in the early 1970s. Alexander Shulgin documented the compound as entry #16 in his 1997 book TiHKAL, providing synthesis procedures, personal bioassays at 10–25 mg, and historical context that continues to inform community knowledge.[5] 4-HO-DET has appeared on research chemical markets since the 2000s, but no clinical trials have been initiated.
The laboratory designation CZ-74 originated from Sandoz's internal compound numbering system. The name ethocybin for the phosphate ester prodrug (CEY-19) was coined by analogy with psilocybin, reflecting the ethyl-for-methyl substitution pattern. Shulgin's TiHKAL entry established the reference dosage and subjective effect profile that circulates in online psychedelic communities, making it one of the earliest tryptamines documented outside institutional research.
Chemistry[edit]
Structural class
4-HO-DET belongs to the 4-substituted tryptamine family — the same structural group as psilocin and 4-HO-MET.[7] It differs from psilocin only at the nitrogen: two ethyl groups replace psilocin's two methyl groups. Its molecular formula is C₁₄H₂₀N₂O (232.32 g/mol), and it has no chirality centers.[9]
A related prodrug, ethocybin (CEY-19), carries a phosphate ester at the 4-position that must be stripped by enzymes before the compound becomes active — the same conversion pathway as psilocybin to psilocin.[7]
Pharmacology[edit]
Mechanism of action
4-HO-DET activates serotonin receptors — the same mechanism as psilocin and other classical psychedelics.[7][9] In animal studies, it fully substitutes for a known hallucinogen, confirming this activity in living systems.[4] At higher doses, additional serotonin pathways add sedation and temperature changes to the perceptual effects.[3][10] No binding measurements specific to 4-HO-DET exist; its pharmacology is inferred from structural analogy to psilocin.
Pharmacokinetics
No human pharmacokinetic data exist for 4-HO-DET. Psilocin — the closest studied structural analog — reaches peak blood levels within 2–4 hours after oral use and clears within 1.5–4 hours.[11][12] Because 4-HO-DET does not require prodrug conversion, it may act faster than psilocybin at equivalent doses, though this is unconfirmed.
Neuroscience[edit]
Where it acts
No neuroimaging studies have been conducted with 4-HO-DET. Based on its confirmed serotonin receptor activity,[4] it is expected to act on neurons in the prefrontal cortex that regulate perception and self-referential thought.[13][14] Disrupting these neurons — as seen with psilocybin and LSD — loosens ego boundaries and dissolves ordinary perceptual filters.[13]
Why it matters
One influential model proposes that serotonin agonists loosen entrenched mental patterns, letting the brain process information with fewer habitual constraints.[13] Psilocin also promotes new neural connections downstream of serotonin receptor activation.[14] Whether 4-HO-DET produces the same neuroplastic effects has not been measured.
Key unknowns include whether 4-HO-DET produces neuroplastic effects comparable to psilocin, whether its receptor residence time differs meaningfully from psilocin (potentially explaining subtle duration or qualitative differences), and whether the reported experiential differences between the two compounds reflect genuine pharmacological distinctions or artifacts of expectation and dose variability in uncontrolled settings.
Subjective Effects[edit]
4-HO-DET produces a warm, moderately paced psychedelic experience that responds strongly to context. Emotional tone, visual intensity, and depth of introspection all shift with psychological state and environment[3] — a calm space can anchor the experience, while an anxious one amplifies it. Material quality also matters: degraded compound produces attenuated, inconsistent effects.[5]
Within the 4-hydroxytryptamine series, 4-HO-DET sits closest to psilocin — similar potency, similar duration, similar emotional warmth.[4] Uncontrolled reports describe a marginally lighter body load and subtle differences in emotional coloring. Shulgin noted distinct textures between the free compound and its prodrug ethocybin, though this has not been confirmed in controlled studies.[5]
Synthesized by Albert Hofmann and Franz Troxler at Sandoz Pharmaceuticals in the late 1950s,[2] 4-HO-DET was among the earliest synthetic psychedelic tryptamines produced. Hanscarl Leuner conducted more than 160 psycholytic therapy sessions with CZ-74 in 1960s Germany, valuing its shorter duration relative to LSD for completing sessions within a standard workday.[3][4] No modern clinical trials have been registered, and the compound circulates in small quantities on research chemical markets.
Subjective effects include geometric visual patterns, emotional intensification, time alteration, and conceptual thought shifts.[5] The experience is reported as qualitatively close to psilocin — a warm, moderately paced tryptamine psychedelic — though uncontrolled reports suggest a marginally lighter body load.[6] Gastrointestinal discomfort, body tremors, and jaw tension are characteristic unsought effects.[4]
4-HO-DET produces no physical dependence; rapid tolerance through 5-HT₂A downregulation makes compulsive redosing self-limiting.[7][1] The primary risk is psychological — acute panic, paranoid ideation, and potential psychotic episodes in predisposed individuals — scaling with dose and vulnerability. No controlled toxicity data, pharmacokinetic parameters, or long-term safety studies exist; the current understanding rests entirely on Shulgin's bioassays and Leuner's unpublished clinical observations.[4]
History[edit]
Discovery
4-HO-DET was synthesized by Albert Hofmann and Franz Troxler at Sandoz Pharmaceuticals in Basel, Switzerland, during the late 1950s.[2] Designated CZ-74 internally, it was part of Sandoz's systematic exploration of psychoactive tryptamine scaffolds following Hofmann's isolation of psilocybin from Psilocybe mexicana in 1958.[8] A phosphate ester prodrug — ethocybin (CEY-19) — was developed in parallel, mirroring the psilocybin-to-psilocin relationship.
Clinical significance
Hanscarl Leuner, the leading proponent of psycholytic psychotherapy in Europe, conducted more than 160 clinical sessions using CZ-74 at his clinic in Germany during the 1960s.[3][4] He valued the compound's shorter duration compared to LSD, which permitted psycholytic sessions to be completed within a standard clinical workday. Leuner's unpublished German-language observations remain the largest body of human clinical data for the compound.
Prohibition and modern use
International prohibition of psychedelic research substances in the late 1960s and early 1970s terminated clinical use of 4-HO-DET. Alexander Shulgin documented the compound as entry #16 in his 1997 book TiHKAL, providing synthesis procedures, personal bioassay reports at 10–25 mg, and historical context that continues to inform community knowledge.[4] 4-HO-DET has appeared on research chemical markets since the 2000s, but no formal clinical trials have been initiated.
The laboratory designation CZ-74 originated from Sandoz's internal compound numbering system. The name ethocybin for the phosphate ester prodrug (CEY-19) was coined by analogy with psilocybin, reflecting the ethyl-for-methyl substitution pattern. Shulgin's TiHKAL entry established the reference dosage and subjective effect profile that circulates in online psychedelic communities, making it one of the earliest tryptamines documented outside institutional research.
Chemistry[edit]
Structural class
4-HO-DET belongs to the 4-substituted tryptamine family. It shares the 4-hydroxyindole pharmacophore — the structural feature responsible for psychedelic activity — with psilocin (4-HO-DMT), 4-HO-MET, and other members of the 4-HO-xT series.[1]
The molecule differs from psilocin only at the amine terminus: two ethyl groups replace psilocin's two methyl groups on the terminal nitrogen. This increases lipophilicity and steric bulk. The compound's prodrug ethocybin (CEY-19) bears a phosphate ester at the 4-position, requiring enzymatic removal to yield the active 4-hydroxy form — the same conversion pathway that links psilocybin to psilocin.[1]
Molecular properties
| Molecular formula | C₁₄H₂₀N₂O |
| Molecular weight | 232.32 g/mol |
The molecule consists of an indole ring system with a hydroxyl group at the 4-position and a 2-(diethylamino)ethyl side chain at the 3-position. 4-HO-DET possesses no chirality centers and exists as a single achiral species.[9]
Physical properties and stability
The free base is a crystalline solid with a melting point of 103–104 °C.[4] The 4-hydroxyl group renders the compound air-sensitive — exposure to oxygen causes visible discoloration and loss of potency through oxidative degradation. Sealed, dark, inert-atmosphere storage at low temperature (−30 °C recommended) is required for stability. No published data on water solubility or partition coefficient were identified.
Structure–activity relationships
Within the 4-hydroxytryptamine series, the N,N-dialkyl substitution pattern modulates potency, duration, and subjective character. The ethyl-for-methyl swap from psilocin to 4-HO-DET increases lipophilicity, which may influence blood-brain barrier penetration and receptor binding kinetics. Conformationally constrained analogs — such as pyrrolidine-containing 4-hydroxytryptamines — introduce chirality, but the flexible diethylamine chain of 4-HO-DET does not.[9]
Pharmacology[edit]
Mechanism of action
4-HO-DET acts primarily at the 5-HT₂A serotonin receptor, the principal target for classical psychedelic effects. The 4-hydroxyindole pharmacophore it shares with psilocin and other psychedelic tryptamines is the structural determinant of this activity.[1][9] Unlike its prodrug ethocybin, the free phenol form is directly active without requiring enzymatic conversion.[1]
The most direct evidence comes from drug-discrimination studies in rats, where 4-HO-DET fully substitutes for the selective 5-HT₂A agonist DOM — confirming hallucinogen-like activity in vivo.[6] In this paradigm, 4-hydroxy tryptamines were uniformly more potent than their 4-acetoxy counterparts, consistent with the free phenol being the active pharmacophore.
By structural analogy to psilocin, 4-HO-DET likely engages additional serotonin receptor subtypes. In mice, psilocin activates 5-HT₁A and 5-HT₂C alongside 5-HT₂A, with each receptor contributing distinct behavioral effects: 5-HT₂A drives the hallmark hallucinogenic response, 5-HT₁A produces sedation, and 5-HT₂C modulates locomotor patterns.[5] At higher doses, 5-HT₁A-mediated effects such as sedation and temperature reduction may become more prominent.[10]
No binding affinity values or potency measurements specific to 4-HO-DET have been published at any receptor. All quantitative pharmacological claims are inferred from structural analogy to psilocin and class-level data.
Pharmacokinetics
No human pharmacokinetic data exist for 4-HO-DET. The closest characterized structural analog is psilocin, which shows oral bioavailability of approximately 53%, reaches peak plasma concentration within 2–4 hours (after psilocybin administration), and has an half-life of 1.5–4 hours.[11][12]
Because 4-HO-DET carries a free hydroxyl group rather than a phosphate ester, it does not require prodrug conversion and may reach the brain faster than psilocybin at equivalent doses — though this has not been confirmed in controlled studies.
The N,N-diethyl groups may alter how the compound is metabolized compared to psilocin's smaller N,N-dimethyl groups, potentially affecting clearance rate and duration. Indole tryptamines are generally processed by liver enzymes and broken down by MAO-A,[13] but the specific metabolic pathway for 4-HO-DET remains uncharacterized.
Neuroscience[edit]
Where it acts
No neuroimaging or electrophysiological studies have been conducted with 4-HO-DET specifically. Based on its confirmed 5-HT₂A-mediated activity,[6] the compound is expected to act on deep-layer pyramidal neurons in the prefrontal cortex.[14][15] In studies with psilocybin and LSD, activation of these neurons disrupts the default mode network — the brain circuitry underlying habitual self-referential thought — producing the characteristic dissolution of ego boundaries, altered emotional processing, and breakdown of ordinary perceptual filtering.[14]
The 5-HT₁A component of 4-HO-DET's presumed receptor profile adds a modulatory layer: 5-HT₁A activation functionally opposes the 5-HT₂A hallucinogenic response,[16] which may explain why higher doses of tryptamine psychedelics shift the experience from perceptual intensity toward sedation and introspection.[10]
Why it matters
The REBUS model (Relaxed Beliefs Under Psychedelics) proposes that 5-HT₂A agonists loosen the grip of entrenched mental patterns, temporarily allowing the brain to process information with fewer top-down constraints.[14] Separately, classical psychedelics including psilocin promote structural neuroplasticity — new dendritic growth and synaptic connections — through pathways downstream of 5-HT₂A activation.[15] Together, these frameworks suggest that compounds like 4-HO-DET may produce both an acute window of cognitive flexibility and longer-lasting neural circuit remodeling, though neither effect has been directly measured for this compound.
Key unknowns include whether 4-HO-DET produces neuroplastic effects comparable to psilocin, whether its receptor residence time differs meaningfully from psilocin (potentially explaining subtle duration or qualitative differences), and whether the reported experiential differences between the two compounds reflect genuine pharmacological distinctions or artifacts of expectation and dose variability in uncontrolled settings.
Subjective Effects[edit]
4-HO-DET's experiential character is strongly shaped by set, setting, and material quality — the free phenol form is air-sensitive, and degraded material (visible as discoloration) may produce attenuated or altered effects.[4] At lower doses, perceptual shifts and emotional warmth predominate; at higher doses, introspection deepens and ego boundaries soften. The experience is reported as notably context-dependent, consistent with the set-and-setting sensitivity characteristic of serotonergic psychedelics.[5]
Within the 4-hydroxytryptamine series, 4-HO-DET is described as qualitatively close to psilocin — similar potency, similar duration, similar emotional tone — with uncontrolled reports suggesting a marginally lighter body load and subtly different emotional coloring.[6] Shulgin noted distinct subjective textures between the free phenol and the phosphate ester (ethocybin) at equivalent doses, though these observations lack controlled confirmation.[4]
Effect Grid
At common doses (15–25 mg oral), the full psychedelic experience manifests: pronounced visual drifting and morphing of surfaces, geometric patterning in peripheral vision and with eyes closed, color enhancement, and depth perception alterations. Thought loops and heightened pattern recognition emerge. Emotional responses intensify significantly — personal insight and meaningful ideation are characteristic. Time distortion is prominent.
Physically, nausea or stomach discomfort may occur during onset. Jaw tension, body tremors, and temperature dysregulation become possible. Increased urination is reported. Pupil dilation is marked.
Functional impairment is significant at this range. The experience demands 5–6 hours of committed time, and residual effects may persist for several additional hours.
Modeled from the effect's dose-dependence curve — not per-substance measurements.
Visual breathing · Holotropic state · Depth perception distortion · Perspective distortion · Symmetrical texture repetition · Music enhancement · Tracers · Brightness alteration · Touch enhancement · After-images · Auditory enhancement · Environmental patterning · Light sensitivity · Sound sensitivity · Visual haze / noise · Visual morphing · Proprioceptive distortion · Auditory distortion · Auditory misinterpretation · Peripheral vision distortion · Spatial disorientation · Visual diffraction · Visual melting · Visual acuity enhancement · Dreaming enhancement · Peripheral misidentification · Vestibular distortion · Visual processing acceleration · Synesthesia · Visual magnification · Olfactory enhancement · Tinnitus · Flashbacks · Object transformations · Internal hallucinations · External hallucinations · Object activation · Visual recursion · Perspective hallucinations · Environmental orbism / cubism · Auditory hallucinations · Olfactory hallucination
Symmetrical texture repetition · Music enhancement · Tracers · Brightness alteration · Touch enhancement · After-images · Auditory enhancement · Environmental patterning · Light sensitivity · Sound sensitivity · Visual haze / noise · Visual morphing · Proprioceptive distortion · Auditory distortion · Auditory misinterpretation · Peripheral vision distortion · Spatial disorientation · Visual diffraction · Visual melting · Visual acuity enhancement · Dreaming enhancement · Peripheral misidentification · Vestibular distortion · Visual processing acceleration · Synesthesia · Visual magnification · Olfactory enhancement · Tinnitus · Flashbacks · Object transformations · Internal hallucinations · External hallucinations · Object activation · Visual recursion · Perspective hallucinations · Environmental orbism / cubism · Auditory hallucinations · Olfactory hallucination
Body high · Stimulation · Appetite suppression · Laughter fits · Tingling / electric sensations · Muscle tension · Wakefulness · Body schema distortion · Dizziness · Heart rate perception changes · Nausea · Tactile euphoria · Vibrations / buzzing · Bodily heaviness · Bodily lightness · Breathing alteration · Dry mouth · Physical fatigue · Restlessness · Yawning · Watery eyes · Excessive sweating · Headache · Insomnia · Muscle relaxation · Sedation · Sexual arousal enhancement · Trembling · Increased urination · Nasal congestion · Involuntary body movements · Kundalini-like energy · Nystagmus (eye wobbles) · Vasoconstriction · Vomiting · Motor control enhancement · Bodily dissociation · Tactile hallucination
Laughter fits · Tingling / electric sensations · Muscle tension · Wakefulness · Body schema distortion · Dizziness · Heart rate perception changes · Nausea · Tactile euphoria · Vibrations / buzzing · Bodily heaviness · Bodily lightness · Breathing alteration · Dry mouth · Physical fatigue · Restlessness · Yawning · Watery eyes · Excessive sweating · Headache · Insomnia · Muscle relaxation · Sedation · Sexual arousal enhancement · Trembling · Increased urination · Nasal congestion · Involuntary body movements · Kundalini-like energy · Nystagmus (eye wobbles) · Vomiting · Motor control enhancement · Bodily dissociation · Tactile hallucination
Immersion enhancement · Novelty enhancement · Thought connectivity · Aesthetic enhancement · Cognitive euphoria · Cognitive flexibility · Openness enhancement · Thought acceleration · Increased nature relatedness · Multiple thought streams · Creativity enhancement · Memory suppression · Thought loops · Cognitive impairment · Focus suppression · Humor enhancement · Cognitive fatigue · Confusion · Information processing suppression · Memory fragmentation · Synchronicity · Thought disorganization · Analysis enhancement · Cognitive dysphoria · Memory replays
Cognitive euphoria · Cognitive flexibility · Openness enhancement · Thought acceleration · Increased nature relatedness · Multiple thought streams · Creativity enhancement · Memory suppression · Thought loops · Cognitive impairment · Focus suppression · Humor enhancement · Cognitive fatigue · Confusion · Information processing suppression · Memory fragmentation · Synchronicity · Thought disorganization · Analysis enhancement · Cognitive dysphoria · Memory replays
Anxiety · Catharsis · Empathy enhancement · Dysphoria
Social connection · Trust enhancement · Communication enhancement · Flow state · Sociability enhancement · Boundary dissolution · Identity alteration · Ego dissolution
Sociability enhancement · Boundary dissolution · Identity alteration · Ego dissolution
Transpersonal visions · Entity contact · Death-rebirth sequence
Recursive awareness
Timeline
First alerts emerge as subtle mood shift, mild restlessness, and faint visual brightening. The free phenol form may produce slightly faster onset than psilocybin's phosphate ester prodrug.
Perceptual changes accelerate: colors intensify, surfaces begin to breathe, and body sensations emerge. Nausea or stomach discomfort is most likely during this phase. Anxiety may accompany the rising intensity.
Maximum perceptual, cognitive, and emotional intensity. Visual distortions, geometric patterning, thought connectivity, and emotional amplification reach their fullest expression. Time distortion is most pronounced.
Effects sustain at reduced intensity. Visual phenomena persist but are less immersive. Cognitive effects remain — thought connectivity and personal insight continue.
Gradual return toward baseline perception. Visual effects fade to subtle shimmering or color enhancement. Cognitive clarity returns progressively.
Residual mood elevation, heightened aesthetic appreciation, and mild cognitive openness may persist for several hours to a day. Some individuals report lingering visual sensitivity.
⚠ Do not drive or operate heavy machinery for the remainder of the day following ingestion.
Safety[edit]
- Acute toxicity
- Low
- Chronic toxicity
- Low
- Withdrawal
- None
- Tolerance buildup
- rapid
- Tolerance reset
- 7 days
- Physical
- None
- Psychological
- Negligible
- Compulsive redosing
- Negligible
- Dose escalation
- Negligible
- Cross-tol.
- psilo · psilocin · LSD
Toxicity
No lethal dose or controlled toxicity data exist for 4-HO-DET in any species.[5] The toxic dose is genuinely unknown.safety citation needed At 20–25 mg, Shulgin reported nausea, tremors, jaw tension, appetite suppression, and increased urination; Leuner observed minimal aftereffects at therapeutic doses.
By class analogy, classical psychedelics have wide margins between active and dangerous doses — no confirmed human deaths from psilocybin toxicity alone have been documented.safety citation needed 4-HO-DET is expected to share this profile, but this has not been confirmed.
Heart and circulation
Serotonin receptor activation raises heart rate, blood pressure, and dilates pupils — expected for 4-HO-DET by class analogy.safety citation needed In healthy individuals at standard doses, clinical significance is likely minimal. Individuals with pre-existing heart conditions may face elevated risk.
Psychological Risks
Acute panic, paranoia, confusion, and deep dysphoria are the most common serious adverse events during psychedelic use, scaling with dose, mindset, and environment.[2] Persistent visual disturbances after the experience ends — a condition called HPPD — are an established risk with this drug class.[15][16] Psychotic episodes may be triggered in individuals with personal or family history of psychosis or bipolar disorder.
Tolerance & Dependence
Tolerance develops rapidly — a single dose can meaningfully reduce sensitivity within 24 hours,[17][6] and it is shared across all classical psychedelics including LSD, psilocybin, mescaline, and DMT.[6][17] Full sensitivity returns over roughly 7 days.
Classical psychedelics do not activate the brain's reward circuitry in the way associated with addiction, and no physical dependence or withdrawal has been documented.[7] Rapid tolerance itself limits compulsive redosing.
Drug Interactions
Serotonin syndrome risk
Tramadol blocks serotonin reuptake.[18] Combining it with 4-HO-DET loads the serotonin system from two directions at once, creating serious risk of dangerous overheating, muscle rigidity, agitation, and cardiovascular instability.[18][19]
MAOIs block the enzyme that breaks down serotonin and tryptamines.[20] Combining them with 4-HO-DET dramatically amplifies effects and creates significant risk of the same dangerous overheating response.
Effect attenuation
SSRIs and SNRIs taken chronically may blunt psychedelic effects through long-term changes to serotonin receptor sensitivity.[21] A theoretical serotonin syndrome risk also exists with acute co-administration.
Seizure risk
Lithium combined with classical psychedelics has been associated with seizures and erratic behavior.citation needed
Contraindications
7 knownThe following contraindications are based on class-level evidence for serotonin agonist psychedelics. No substance-specific data exist for 4-HO-DET.
Absolute:
- Personal or family history of psychotic disorders
- Concurrent MAOI use — serotonin syndrome risk
- Concurrent tramadol use — serotonin syndrome risk[18]
- Concurrent lithium use — seizure riskcitation needed
Relative:
- Heart conditions — sympathomimetic effects may pose risksafety citation needed
- Bipolar disorder — risk of manic or psychotic episode
- Pregnancy — no safety data exist
- Concurrent SSRI/SNRI use — unpredictable effect modification and theoretical serotonin risk[21]
Harm Reduction[edit]
Forms & Identification
4-HO-DET degrades visibly when exposed to air. Any discoloration — darkening or browning — indicates oxidative breakdown and reduced potency.[5] Material that has changed color since purchase should be treated as partially degraded and inconsistent in strength.
Reagent testing confirms the presence of a 4-hydroxytryptamine but cannot distinguish between members of the series or assess purity. Quantitative analysis requires more advanced methods.
Guidelines
- Test all material with appropriate reagent kits before use
- Start with a low dose to assess individual sensitivity, particularly with material of unknown provenance
- Weigh doses with a milligram-precision scale — volumetric dosing is unreliable with air-sensitive compounds
- Allow at least 7 days between sessions for full tolerance reset
- Prepare the environment in advance: comfortable temperature, access to water, minimal obligations for the duration
- Eat lightly several hours beforehand to reduce nausea
- Keep a trusted, sober companion present — especially at unfamiliar doses
- Avoid redosing during the experience; rapid tolerance means additional material is unlikely to deepen effects and may extend duration unpredictably
Set & Setting
As a serotonergic psychedelic, 4-HO-DET's effects are substantially shaped by psychological state and physical environment. A calm, familiar setting with trusted companions reduces the likelihood of acute distress.
Avoid use during periods of emotional lability, unresolved anxiety, or significant life stress. First experiences benefit from a sober companion familiar with the psychedelic state.
Aftercare & integration. The hours and days following a psychedelic experience are a sensitive period. Allow time for rest and reflection — avoid demanding obligations on the day of use and ideally the following day. Journaling or drawing during the afterglow can help capture insights before they fade.
Difficult or confusing experiences benefit from processing with a trusted person or a therapist experienced with psychedelic integration. Persistent anxiety, depersonalization, or visual disturbances lasting more than a few days warrant professional consultation.
Recovery & Support
Classical psychedelics carry low addiction liability, and compulsive use patterns are rare. If use is becoming a way to avoid difficult emotions rather than explore them, or if frequency is increasing despite diminishing returns, reassessment is warranted. Support resources include psychedelic-informed therapists, peer support organizations such as the Fireside Project, and general mental health services. Psychological dependence on any substance — even one with no physical withdrawal — deserves the same attention as any other pattern of avoidance.
Recovery resources, crisis lines, and support pathways → View all
Emergency Response
Recognizing an emergency: Most difficult psychedelic experiences are uncomfortable but not medically dangerous. Seek immediate help if the person shows signs of self-harm intent, complete disconnection from reality with dangerous behavior, seizures, sustained chest pain, or loss of consciousness.
Immediate steps:
- Call emergency services if the person is at risk of harming themselves or others, is unresponsive, or is experiencing seizures
- Move the person to a quiet, safe space away from hazards
- Speak calmly and reassuringly — remind them where they are, that they took a substance, and that the effects will end
- Do not physically restrain unless there is immediate danger of self-harm or harm to others
- Do not administer other substances to "counteract" the experience
- If the person is unconscious, place them in the recovery position and monitor breathing
What to tell the dispatcher: Name the substance (4-HO-DET, a psychedelic tryptamine), estimated dose, time of ingestion, and current symptoms. Good Samaritan laws in many jurisdictions protect people who call for help during drug-related emergencies.
Legal Status[edit]
4-HO-DET is rarely scheduled by name; it falls under generic tryptamine provisions, structural analog statutes, or blanket novel psychoactive substance legislation in most jurisdictions.
| Jurisdiction | Classification | Key provisions |
|---|---|---|
| United States | Not specifically scheduled | Not listed under the Controlled Substances Act. Subject to prosecution under the Federal Analogue Act (21 U.S.C. § 813) as a structural and pharmacological analog of psilocin (Schedule I) if intended for human consumption[1] |
| United Kingdom | Class A | Controlled under the Misuse of Drugs Act 1971 via the generic tryptamine catch-all clause. Additionally covered by the Psychoactive Substances Act 2016[1] |
| Canada | Not explicitly controlled | Not listed under the Controlled Drugs and Substances Act as of 2025citation needed |
| Germany | Likely controlled under NpSG | The Neue-psychoaktive-Stoffe-Gesetz (NpSG) covers structural classes of tryptamines with psychoactive properties. Specific verification for 4-HO-DET not confirmedcitation needed |
| Australia | Likely Schedule 9 | Probable classification under broad tryptamine provisions. Not directly verifiedcitation needed |
Analog and prodrug considerations
In jurisdictions with analog legislation — notably the United States — 4-HO-DET's close structural similarity to psilocin makes prosecution under analog statutes plausible.[1] The prodrug ethocybin (CEY-19) may face the same scrutiny. The 4-acetoxy analog (4-AcO-DET) functions as a prodrug for 4-HO-DET and may be treated identically under analog statutes.
Legal status varies by jurisdiction and changes without notice. This information is not legal advice.
Safety[edit]
- Acute toxicity
- Low
- Chronic toxicity
- Low
- Withdrawal
- None
- Tolerance buildup
- rapid
- Tolerance reset
- 7 days
- Physical
- None
- Psychological
- Negligible
- Compulsive redosing
- Negligible
- Dose escalation
- Negligible
- Cross-tol.
- psilo · psilocin · LSD
Toxicity
No lethal dose, therapeutic index, or controlled toxicity data exist for 4-HO-DET in any species.[4] No case reports of acute poisoning or fatal overdose have been published. The toxic dose is genuinely unknown.safety citation needed
At doses of 20–25 mg, Shulgin reported gastrointestinal discomfort, body tremors, jaw tension, loss of appetite, and increased urination. Leuner noted a favorable safety profile with minimal aftereffects at therapeutic doses. These observations derive from a small number of exposures and do not substitute for formal toxicological assessment.
By class analogy, classical serotonergic psychedelics exhibit wide therapeutic indices — psilocybin's estimated lethal dose in rats far exceeds the human psychoactive range, and no confirmed human fatalities from psilocybin toxicity alone have been documented.safety citation needed 4-HO-DET is expected to share this favorable acute toxicity profile, though this remains unconfirmed.
Heart and circulation
Serotonin receptor agonism produces increased heart rate, blood pressure elevation, and pupil dilation — effects documented across the psychedelic tryptamine class and expected for 4-HO-DET. In healthy individuals at standard doses, clinical significance is minimal based on psilocybin safety data, but individuals with pre-existing heart conditions may face elevated risk.safety citation needed
Psychological Risks
Acute psychological distress ("challenging experiences") is the most common serious adverse event during psychedelic use, characterized by intense anxiety, paranoia, confusion, and dysphoria. Incidence scales with dose, set, and setting.[3]
Hallucinogen persisting perception disorder (HPPD) is an established risk for serotonin 2A receptor agonists. The majority of documented cases involve drugs with 5-HT₂A agonist activity,[17] and at least one case has been confirmed following use of a 4-hydroxylated tryptamine specifically.[18] No HPPD cases specific to 4-HO-DET have been reported.
Psychotic episodes may be precipitated in individuals with personal or family history of psychotic disorders or bipolar disorder. No substance-specific data exist for 4-HO-DET.
Tolerance & Dependence
Classical psychedelics develop rapid tolerance through downregulation of 5-HT₂A receptors in the brain.[19][7] In mice, tolerance to the hallucinogenic response develops within 24 hours of a single dose and progresses over 4 days of repeated use.[7] Full sensitivity returns over approximately 7 days.
Cross-tolerance occurs with all 5-HT₂A agonist psychedelics: LSD, psilocybin, mescaline, DMT, and other 4-substituted tryptamines.[7][19]
No physical dependence or withdrawal has been documented for 4-HO-DET or for classical psychedelics as a class. The rapid development of tolerance itself limits compulsive redosing. Classical psychedelics do not activate the brain's reward circuitry in a manner associated with addiction.[1]
Drug Interactions
Serotonin syndrome risk
Tramadol blocks serotonin reuptake.[20] Combined with a 5-HT₂A agonist like 4-HO-DET, the dual serotonergic load creates risk of serotonin syndrome — a potentially life-threatening condition involving dangerously elevated body temperature, muscle rigidity, agitation, and cardiovascular instability.[20][21]
MAOIs (monoamine oxidase inhibitors) are expected to potentiate 4-HO-DET by blocking its metabolic breakdown and elevating serotonin levels. Harmine, a natural MAO-A inhibitor, has been shown to inhibit tryptamine metabolism in laboratory studies.[13] Serotonin syndrome risk is significant.
Effect attenuation
SSRIs and SNRIs taken chronically may blunt or attenuate psychedelic effects through long-term changes to serotonin receptor sensitivity.[22] A theoretical serotonin syndrome risk exists with acute co-administration, though controlled psilocybin studies have not identified serious adverse events from this combination.
Seizure risk
Lithium combined with classical psychedelics has been associated with increased seizure risk and erratic behavior.citation needed
Cannabis
No published data exist on the interaction between 4-HO-DET and cannabis. The interaction profile is genuinely unknown.[22]
Contraindications
7 knownThe following contraindications are derived from class-level evidence for 5-HT₂A agonist psychedelics. No substance-specific contraindication data exist for 4-HO-DET.
Absolute:
- Personal or family history of psychotic disorders
- Concurrent MAOI use — serotonin syndrome risk
- Concurrent tramadol use — serotonin syndrome risk[20]
- Concurrent lithium use — seizure riskcitation needed
Relative:
- Heart conditions — sympathomimetic effects may pose risksafety citation needed
- Bipolar disorder — risk of manic or psychotic episode
- Pregnancy — no safety data exist
- Concurrent SSRI/SNRI use — unpredictable effect modification and theoretical serotonin risk[22]
Harm Reduction[edit]
Forms & Identification
4-HO-DET's air sensitivity is the primary identification concern. The free base degrades visibly when exposed to oxygen — any discoloration (darkening, browning) indicates oxidative breakdown and reduced potency. Material that has changed color since purchase should be treated as partially degraded and potentially inconsistent in strength. Reagent testing confirms the presence of a 4-hydroxytryptamine but cannot distinguish between members of the series or assess purity; quantitative analysis requires more advanced methods.
Guidelines
- Test all material with appropriate reagent kits before use
- Start with a low dose to assess individual sensitivity, particularly with material of unknown provenance
- Weigh doses with a milligram-precision scale — volumetric dosing is unreliable with air-sensitive compounds
- Allow at least 7 days between sessions for full tolerance reset
- Prepare the environment in advance: comfortable temperature, access to water, minimal obligations for the duration
- Eat lightly several hours beforehand to reduce nausea
- Keep a trusted, sober companion present — especially at unfamiliar doses
- Avoid redosing during the experience; rapid tolerance means additional material is unlikely to deepen effects and may extend duration unpredictably
Set & Setting
As a serotonergic psychedelic with strong context sensitivity, 4-HO-DET's effects are substantially shaped by psychological state and physical environment. A calm, familiar setting with trusted companions reduces the likelihood of acute distress. Avoid use during periods of emotional lability, unresolved anxiety, or significant life stress. First experiences benefit from a sober companion familiar with the psychedelic state.
Aftercare & integration. The hours and days following a psychedelic experience are a sensitive period. Allow time for rest and reflection — avoid demanding obligations on the day of use and ideally the following day. Journaling or drawing during the afterglow period can help capture insights before they fade.
Difficult or confusing experiences benefit from processing with a trusted person or a therapist experienced with psychedelic integration. Persistent anxiety, depersonalization, or visual disturbances lasting more than a few days after use warrant professional consultation.
Recovery & Support
Classical psychedelics carry low addiction liability, and compulsive use patterns are rare. If use is becoming a way to avoid difficult emotions rather than explore them, or if frequency is increasing despite diminishing returns, reassessment is warranted. Support resources include psychedelic-informed therapists, peer support organizations such as the Fireside Project, and general mental health services. Psychological dependence on any substance — even one with no physical withdrawal — deserves the same attention as any other pattern of avoidance.
Recovery resources, crisis lines, and support pathways → View all
Emergency Response
Recognizing an emergency: Most difficult psychedelic experiences are uncomfortable but not medically dangerous. Seek immediate help if the person shows signs of self-harm intent, complete disconnection from reality with dangerous behavior, seizures, sustained chest pain, or loss of consciousness.
Immediate steps:
- Call emergency services if the person is at risk of harming themselves or others, is unresponsive, or is experiencing seizures
- Move the person to a quiet, safe space away from hazards
- Speak calmly and reassuringly — remind them where they are, that they took a substance, and that the effects will end
- Do not physically restrain unless there is immediate danger of self-harm or harm to others
- Do not administer other substances to "counteract" the experience
- If the person is unconscious, place them in the recovery position and monitor breathing
What to tell the dispatcher: Name the substance (4-HO-DET, a psychedelic tryptamine), estimated dose, time of ingestion, and current symptoms. Good Samaritan laws in many jurisdictions protect people who call for help during drug-related emergencies.
Legal Status[edit]
4-HO-DET occupies an ambiguous legal position in most jurisdictions. It is rarely scheduled by name; instead, it falls under generic tryptamine catch-all provisions, structural analog statutes, or blanket novel psychoactive substance (NPS) legislation where such frameworks exist. Legal status varies significantly by jurisdiction and is subject to change without notice.
| Jurisdiction | Classification | Key provisions |
|---|---|---|
| United States | Not specifically scheduled | Not listed under the Controlled Substances Act. Subject to prosecution under the Federal Analogue Act (21 U.S.C. § 813) as a structural and pharmacological analog of psilocin (Schedule I) if intended for human consumption[2] |
| United Kingdom | Class A | Controlled under the Misuse of Drugs Act 1971 via the generic tryptamine catch-all clause. Additionally covered by the Psychoactive Substances Act 2016[2] |
| Canada | Not explicitly controlled | Not listed under the Controlled Drugs and Substances Act as of 2025citation needed |
| Germany | Likely controlled under NpSG | The Neue-psychoaktive-Stoffe-Gesetz (NpSG) covers structural classes of tryptamines with psychoactive properties. Specific verification for 4-HO-DET not confirmedcitation needed |
| Australia | Likely Schedule 9 | Probable classification under broad tryptamine provisions. Not directly verifiedcitation needed |
Analog and prodrug considerations
In jurisdictions with structural analog legislation (notably the United States), 4-HO-DET's close structural relationship to psilocin — differing only in the N,N-diethyl versus N,N-dimethyl substitution — makes prosecution under analog provisions plausible.[2] The prodrug ethocybin (CEY-19) may face similar scrutiny, as the phosphate ester relationship mirrors that of psilocybin to psilocin.
The 4-acetoxy analog (4-AcO-DET) is sometimes marketed as legally distinct due to the additional ester modification, but it functions as a prodrug for 4-HO-DET and may be treated identically under analog statutes.
Frequently asked questions
How long does 4-HO-DET last?
Total duration by route of administration — Oral: 4 – 6 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 4-HO-DET?
Psychedex publishes a dosage table for 4-HO-DET 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 4-HO-DET?
The highest-severity documented interactions for 4-HO-DET: MAOIs (Lethal), Dopamine agonists (Dangerous), GHB, Baclofen (Dangerous), GHB, GBL (Dangerous), Ibogaine (Dangerous). See the interactions section for the full list with mechanisms and severity levels.
Is 4-HO-DET addictive?
Psychedex records tolerance and dependence data rather than a yes/no rating. Recorded tolerance indicators for 4-HO-DET: tolerance builds rapid; full reset takes 7 days; cross-tolerance develops with psilocybin, psilocin, LSD, mescaline, DMT, 4-AcO-DMT, 4-HO-MET, 4-AcO-DET. See the article's dependence and safety sections for recorded dependence data.
experience reports
No experience reports yet. Be the first to contribute.
First-person accounts of subjective effects, timing, and outcomes — submitted for harm reduction.
references
- [1]
- [2] ^abcPassie T, Guss J, Krähenmann R (2022) Lower-Dose Psycholytic Therapy - A Neglected Approach — Frontiers in Psychiatry doi:10.3389/fpsyt.2022.1020505
- [3] ^abcHalberstadt AL, Koedood L, Powell SB, Geyer MA (2011) Differential contributions of serotonin receptors to the behavioral effects of indoleamine hallucinogens in mice — Journal of Psychopharmacology doi:10.1177/0269881110388326
- [4] ^abcdGatch MB, Hoch A, Carbonaro TM (2021) Discriminative Stimulus Effects of Substituted Tryptamines in Rats — ACS Pharmacology & Translational Science doi:10.1021/acsptsci.0c00173
- [5]
- [6] ^abcde la Fuente Revenga M, Jaster AM, McGinn J, Silva G, Saha S, Gonzalez-Maeso J (2022) Tolerance and Cross-Tolerance among Psychedelic and Nonpsychedelic 5-HT2A Receptor Agonists in Mice — ACS Chemical Neuroscience doi:10.1021/acschemneuro.2c00170
references
- [1]
- [2]
- [3] ^abcPassie T, Guss J, Krähenmann R (2022) Lower-Dose Psycholytic Therapy - A Neglected Approach — Frontiers in Psychiatry doi:10.3389/fpsyt.2022.1020505
- [4]
- [5] ^abcHalberstadt AL, Koedood L, Powell SB, Geyer MA (2011) Differential contributions of serotonin receptors to the behavioral effects of indoleamine hallucinogens in mice — Journal of Psychopharmacology doi:10.1177/0269881110388326
- [6] ^abcdGatch MB, Hoch A, Carbonaro TM (2021) Discriminative Stimulus Effects of Substituted Tryptamines in Rats — ACS Pharmacology & Translational Science doi:10.1021/acsptsci.0c00173