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1B-LSD
1-butanoyl-d-lysergic acid diethylamide
1B-LSD (1-butanoyl-lysergic acid diethylamide) is a synthetic psychedelic of the lysergamide class. It is a prodrug of LSD — the body converts it to LSD, which is the actual active compound. It activates serotonin receptors in the brain,[1] producing the perceptual and cognitive shifts characteristic of classical psychedelics.
1B-LSD (1-butanoyl-lysergic acid diethylamide) is a semi-synthetic psychedelic of the lysergamide class. It is a prodrug of LSD, distinguished by a four-carbon acyl group at the indole nitrogen. 1B-LSD is a presumed 5-HT₂A receptor agonist,[1] producing its effects by disrupting the brain's default filtering of sensory and cognitive input.
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It appeared on the research chemical market in August 2016, with no prior record in the scientific literature.[2] It was the fourth in a series of chemically modified LSD derivatives, each designed to exploit gaps in controlled substance scheduling law. It remains unscheduled by name in most countries and circulates in small quantities as blotter or pellets.
Subjective effects include geometric visual patterns, color enhancement, time alteration, thought acceleration, and ego dissolution. The experience is widely reported as indistinguishable from LSD — long, analytically sharp, with a buzzing physical stimulation unlike the sedation typical of other psychedelics. Thought loops, anxious fixation, and difficulty sleeping through the extended offset are common unsought effects.
1B-LSD does not produce physical dependence, and the active compound LSD has no established lethal dose in humans.[3] The primary danger is psychological: acute panic and destabilizing ego dissolution scale with dose[4] and pre-existing anxiety.[5] No clinical studies of 1B-LSD have been conducted — all safety conclusions rest on the LSD evidence base and an unconfirmed prodrug hypothesis.
History[edit]
Discovery
1B-LSD appeared on the research chemical market in August 2016, with no prior history in the scientific literature.[2] Its original synthesizer is unknown. The first scientific characterization was published in 2019 by Brandt and colleagues.[2]
The N1-acyl lysergamide series
It belongs to a series of LSD derivatives, each carrying a different carbon chain attached to the same position on the molecule. The lineage runs from ALD-52 (first synthesized in the 1950s)[6][7] through 1P-LSD[8] to 1B-LSD (2016)[2] and on to 1CP-LSD, which provided the first direct evidence of LSD release in human serum.[9] Each new compound was designed to sit just outside the scheduling laws that had caught its predecessor.
Regulatory response
Germany explicitly controlled 1B-LSD under its novel psychoactive substance law in July 2019,[10] and it falls under the United Kingdom's blanket Psychoactive Substances Act 2016. Most other jurisdictions have not named it directly.
Chemistry[edit]
Structural identity
1B-LSD (1-butanoyl-d-lysergic acid diethylamide) is a synthetic lysergamide — a chemical family built on the ergoline ring system, the same core scaffold as LSD. It is distinguished by a four-carbon butanoyl chain at the indole nitrogen, placing it structurally between 1P-LSD (three-carbon chain) and longer-chain relatives in the same series.[2] Its molecular formula is C₂₄H₃₁N₃O₂ (molecular weight 393.5 g/mol).
The butanoyl chain is also the key to how 1B-LSD works. Enzymes in the blood strip it away after ingestion, releasing LSD as the active compound.[2] This makes 1B-LSD a prodrug — a compound that is itself pharmacologically inactive but converts to an active substance in the body.
Pharmacology[edit]
Mechanism of action
1B-LSD is a prodrug of LSD. Enzymes in the blood strip away the butanoyl group after ingestion, releasing LSD as the active compound.[2][1] Related N1-acyl derivatives have been confirmed to release LSD in plasma,[9] but this conversion has not been directly verified for 1B-LSD itself — prodrug status is strongly inferred from structural analogy. inferred
LSD as active moiety
Once converted, the pharmacology is that of LSD. LSD activates serotonin receptors on cortical neurons,[3] disrupting the brain's normal filtering of sensory input and producing the psychedelic state. Structural studies reveal why the effects last so long: the receptor folds over the LSD molecule like a lid, trapping it and prolonging receptor activation.[11][12]
Pharmacokinetics
No human pharmacokinetic data exist for 1B-LSD. LSD itself reaches peak blood levels about 1–1.5 hours after oral ingestion[13] and clears with a half-life of roughly 3–5 hours.[14] People with slow CYP2D6 enzyme activity — a liver enzyme that breaks down LSD — experience roughly 75% higher exposure, with prolonged and intensified effects.[15]
Neuroscience[edit]
Where it acts
No neuroimaging studies of 1B-LSD exist — the following is established for LSD and expected to apply after prodrug conversion. LSD activates serotonin receptors on cortical neurons,[3] opening a broader flow of perceptual and associative signals than the brain normally allows. It also disrupts the brain network tied to the sense of self; stronger disruption tracks with the intensity of ego dissolution.[3]
Why it matters
One leading framework proposes that psychedelics weaken the brain's established predictive patterns while amplifying incoming signals — allowing rigid beliefs and emotional patterns to shift. This may explain both the acute experience and lasting effects seen in clinical trials for depression and addiction. LSD also stimulates growth of new neural connections through signaling pathways involving BDNF,[16] and these changes outlast the experience itself.
Whether 1B-LSD crosses the blood-brain barrier intact or is fully converted to LSD in the bloodstream first remains unknown. Individual differences in the enzymes that cleave the butanoyl chain may produce unpredictable variation in effective dose — a source of variability absent with LSD itself. The gap between mouse potency data (1B-LSD at roughly 14% of LSD's potency) and human reports of near-equivalent effects has not been explained.[1]
Subjective Effects[edit]
The 1B-LSD experience is vivid, analytically sharp, and long-lasting — defined by an unusual clarity of thought alongside perceptual intensification. Set and setting shape the outcome dramatically: the same dose can produce serene contemplation or acute distress depending on the user's emotional state and surroundings.[5]
Most users describe the experience as indistinguishable from LSD. Compared to psilocybin, it runs longer and carries more physical stimulation — the body feels buzzed and alert rather than sedated. The cognitive tone tends toward analytical sharpness rather than the introspective warmth typical of tryptamine psychedelics.
1B-LSD appeared on the research chemical market in August 2016 with no prior record in the scientific literature.[2] It was the fourth in a series of N1-acylated LSD derivatives — following ALD-52, 1P-LSD, and 1CP-LSD — each designed to exploit gaps in controlled substance scheduling. It remains unscheduled by name in most jurisdictions, circulating in small quantities as blotter or pellets among research chemical users.
Subjective effects include geometric visual patterns, color enhancement, time alteration, thought acceleration, and ego dissolution. The experience is reported as indistinguishable from LSD — a slow-building, analytically sharp alteration of perception and cognition accompanied by a buzzing somatic stimulation that distinguishes the lysergamide body feel from tryptamine sedation. Thought loops, anxious fixation, and difficulty sleeping through the extended offset are common unsought effects.
1B-LSD produces no physical dependence, and its active moiety LSD has no established lethal dose in humans[3] — rapid tolerance after a single dose makes compulsive redosing self-limiting.[4] The primary risk is psychological: high-dose experiences can produce acute panic and destabilizing ego dissolution, scaling with dose[5] and pre-existing anxiety.[6] No clinical trials or human pharmacokinetic studies of 1B-LSD have been conducted — all safety inferences rest on the LSD evidence base and an unconfirmed prodrug hypothesis.
History[edit]
Discovery
1B-LSD appeared on the research chemical market in August 2016 with no prior history in the scientific literature.[2] Its original synthesizer is unknown. The first analytical and behavioral characterization was published by Brandt and colleagues in 2019 as Part V of the "Return of the lysergamides" series in Drug Testing and Analysis, using a research sample sourced from Synex Synthetics BV in the Netherlands.[2]
The N1-acyl lysergamide series
1B-LSD belongs to a series of N1-acylated LSD derivatives that appeared sequentially on the research chemical market, each bearing a different acyl chain at the indole nitrogen. The lineage begins with ALD-52 (acetyl, first synthesized in the 1950s),[7][8] continues through 1P-LSD (propanoyl, circa 2013–2015)[9] and 1B-LSD (butanoyl, 2016),[2] and extends to 1CP-LSD (cyclopropanoyl), which provided the first direct evidence of LSD release from an N1-acyl derivative in human serum.[10] The use of N1-alkylated lysergamide derivatives to circumvent scheduling was anticipated as early as 1988 in a Drug Enforcement Administration report.[11]
Regulatory response
Germany explicitly controlled 1B-LSD under the Neue-psychoaktive-Stoffe-Gesetz (NpSG) in July 2019,[11] and it falls under the United Kingdom's blanket Psychoactive Substances Act 2016. Each new N1-acyl variant appeared in jurisdictions where its predecessor had been controlled — a pattern of iterative circumvention and legislative response that defines this compound series.
Chemistry[edit]
Structural identity
1B-LSD (1-butanoyl-d-lysergic acid diethylamide) belongs to the ergoline lysergamide family — compounds built on a tetracyclic ergoline core with a diethylamide group at the C-9 position. Its defining feature is a butanoyl (four-carbon acyl) group at the indole nitrogen (N1), placing it between 1P-LSD (propanoyl, three carbons) and longer-chain analogs in the N1-acylated LSD series.[2]
The systematic lengthening of the acyl chain across this series — from the two-carbon acetyl group of ALD-52 through propanoyl, butanoyl, hexanoyl,[12] and dodecanoyl[7] — has provided a framework for studying how substituent size affects hydrolysis rate and in vivo potency. 1B-LSD is a constitutional isomer of 1P-ETH-LAD, sharing the molecular formula C₂₄H₃₁N₃O₂ but differing in the location of its structural modifications.[2]
Molecular properties
| Molecular formula | C₂₄H₃₁N₃O₂ |
| Molecular weight | 393.5 g/mol |
Stereochemistry
1B-LSD retains the two chirality centers of the ergoline scaffold at positions C-5 and C-8, in the (6aR,9R) configuration required for serotonin receptor binding. The mirror-image l-isomer is pharmacologically inactive. The butanoyl group at N1 introduces no additional stereocenters.
Physical properties
No published data exist for the melting point, solubility, or crystal structure of 1B-LSD in any salt or free-base form. The compound is distributed on blotter paper or as pellets.[13] As with all lysergamides, it is expected to be sensitive to light, heat, and oxidation, requiring cool, dark, anhydrous storage.
Pharmacology[edit]
Mechanism of action
1B-LSD functions as a prodrug of LSD. The butanoyl group at the indole nitrogen is cleaved by enzymes in the blood and tissues, releasing LSD as the active compound.[2][1] This deacylation has been directly demonstrated for close structural relatives: high LSD plasma levels appear in rats after administration of ALD-52 and 1P-LSD,[1] and 1CP-LSD releases LSD when incubated with human serum.[10] ALD-52, the prototype of the series, is confirmed as a prodrug with hydrolysis to LSD responsible for its activity.[7]
Direct deacylation data specific to 1B-LSD have not been published — prodrug status is strongly inferred from structural analogy and pharmacological profile but remains formally unconfirmed. inferred In its intact form, 1B-LSD shows substantially reduced receptor binding, weak or absent activity at serotonin receptors in functional assays, yet induces head twitches in mice with relatively high potency — a dissociation consistent with in vivo conversion to LSD as the active species.[1]
LSD as active moiety
After conversion, the pharmacology is that of LSD. LSD acts primarily as a partial agonist at the serotonin 5-HT₂A receptor on cortical pyramidal neurons.[3] It also engages a broad range of serotonin, dopamine, adrenergic, and histamine receptor subtypes.[8] The psychedelic effects are 5-HT₂A-mediated: the selective antagonist ketanserin completely blocks all subjective effects of LSD in controlled human studies.[5]
Structural studies have revealed why LSD's effects last so long: the receptor's extracellular loop folds over the binding pocket like a lid, trapping the molecule and prolonging its occupancy.[14][15]
Pharmacokinetics
No human pharmacokinetic study exists for 1B-LSD. The compound is presumed to undergo oral absorption followed by enzymatic conversion to LSD, but the rate and efficiency of this conversion in humans are unknown.
LSD itself shows dose-proportional pharmacokinetics, reaching peak blood levels approximately 1–1.5 hours after oral administration.[16][17] Its half-life ranges from roughly 3 to 5 hours.[16][18]
LSD is broken down primarily by the liver enzyme CYP2D6.[19][20] People who metabolize drugs slowly through this enzyme (CYP2D6 poor metabolizers) experience roughly 75% higher LSD exposure, with prolonged and intensified effects.[19] The CYP2D6 inhibitor paroxetine increases LSD blood levels by approximately 1.4- to 1.5-fold.[20]
Neuroscience[edit]
Where it acts
No neuroimaging studies of 1B-LSD have been conducted. The following mechanisms are established for LSD and expected to apply via the prodrug conversion.
The cellular trigger is 5-HT₂A receptor activation on layer V pyramidal neurons in the cortex.[3] This increases excitatory signaling and disrupts the thalamic gate that normally filters sensory input before it reaches conscious awareness. The result is a broadening of information flow — perceptual, emotional, and associative streams that are ordinarily separated become simultaneously accessible, producing the distortions, novel associations, and emotional intensification characteristic of the psychedelic state. LSD also reduces the coherence of the default mode network (DMN), a set of brain regions tied to the sense of self. The degree of DMN disruption tracks with the intensity of ego dissolution.[3]
Why it matters
The leading explanatory framework — Relaxed Beliefs Under Psychedelics (REBUS) — proposes that psychedelics weaken the brain's established predictive models while amplifying incoming sensory signals. This flattening of the brain's inference hierarchy is thought to allow rigid beliefs to be revised, potentially explaining both the acute experience and lasting therapeutic effects observed in depression and addiction trials.
LSD and related psychedelics also promote structural brain changes — growth of new dendritic branches and synaptic connections — through signaling pathways involving BDNF and mTOR.[21] These changes outlast the acute drug experience and may underlie the persistent psychological effects reported after a single dose.
Whether 1B-LSD crosses the blood–brain barrier intact or is fully converted to LSD in the bloodstream remains unknown. If some central conversion occurs, it could produce different spatial and temporal patterns of receptor activation compared to LSD taken directly.
Subjective Effects[edit]
The 1B-LSD experience unfolds gradually, reflecting the time required for prodrug conversion to LSD. Set and setting powerfully modulate the outcome across the entire dose range — the same amount can produce serene contemplation or acute distress depending on the user's psychological state and environment.[6] At lower doses, effects center on perceptual enhancement and mild cognitive shifts; at higher doses, the experience deepens into full perceptual restructuring and ego dissolution.
Most users report the qualitative character as indistinguishable from LSD. Compared to psilocybin, the experience runs longer, carries more physical stimulation, and tends toward a sharper, more analytical cognitive tone rather than the introspective warmth often attributed to tryptamine psychedelics.
Effect Grid
At common doses (75–150 µg oral), the full psychedelic experience emerges: pronounced open- and closed-eye visuals including geometric patterns overlaying surfaces, colour shifting, drifting and morphing of objects, and tracers behind moving objects. Time distortion becomes significant — hours may feel like minutes or vice versa. Thought connectivity increases dramatically, often producing novel associations, personal insights, and a sense of conceptual depth. Emotional intensification is marked; music, art, and interpersonal interactions can feel profoundly meaningful.
Physically, pupil dilation is prominent. Stimulation, jaw tension (trismus), temperature dysregulation, and peripheral vasoconstriction (cold extremities) are common. Nausea is less frequent than with tryptamine psychedelics but may occur during the come-up.
Functional impairment is substantial. The experience demands 8–12 hours of commitment. Sleep is impossible during the active phase and may remain difficult for several hours after resolution.
Modeled from the effect's dose-dependence curve — not per-substance measurements.
Auditory enhancement · Depth perception distortion · Tracers · Geometry · Visual breathing · Symmetrical texture repetition · Touch enhancement · Perspective distortion · After-images · Brightness alteration · Environmental patterning · Light sensitivity · Sound sensitivity · Visual morphing · Ganzfeld effect · Sleep-transition hallucinations · Auditory distortion · Visual melting · Auditory misinterpretation · Dreaming suppression · Peripheral vision distortion · Proprioceptive distortion · Spatial disorientation · Visual diffraction · Visual haze / noise · Synesthesia · Visual acuity enhancement · Peripheral misidentification · Vestibular distortion · Visual magnification · Visual processing acceleration · Olfactory enhancement · Taste enhancement · Flashbacks · Object transformations · Visual recursion · Internal hallucinations · Object activation · Visual scenery slicing · External hallucinations · Environmental orbism / cubism · Perspective hallucinations · Auditory hallucinations · Visual flipping · Shadow people · Persisting hallucinations
Visual breathing · Symmetrical texture repetition · Touch enhancement · Perspective distortion · After-images · Brightness alteration · Environmental patterning · Light sensitivity · Sound sensitivity · Visual morphing · Ganzfeld effect · Sleep-transition hallucinations · Auditory distortion · Visual melting · Auditory misinterpretation · Dreaming suppression · Peripheral vision distortion · Proprioceptive distortion · Spatial disorientation · Visual diffraction · Visual haze / noise · Synesthesia · Visual acuity enhancement · Peripheral misidentification · Vestibular distortion · Visual magnification · Visual processing acceleration · Olfactory enhancement · Taste enhancement · Flashbacks · Object transformations · Visual recursion · Internal hallucinations · Object activation · Visual scenery slicing · External hallucinations · Environmental orbism / cubism · Perspective hallucinations · Auditory hallucinations · Visual flipping · Shadow people · Persisting hallucinations
Stimulation · Spontaneous body sensations · Appetite suppression · Insomnia · Body high · Heart rate perception changes · Physical fatigue · Muscle tension · Bodily lightness · Body schema distortion · Breathing alteration · Laughter fits · Restlessness · Tactile euphoria · Temperature dysregulation · Tingling / electric sensations · Vibrations / buzzing · Nausea · Abnormal heartbeat · Excessive sweating · Sexual arousal enhancement · Bodily heaviness · Bodily pressures · Dehydration sensation · Dizziness · Dry mouth · Kundalini-like energy · Nystagmus (eye wobbles) · Increased urination · Involuntary body movements · Bruxism · Headache · Pain enhancement · Respiratory stimulation · Trembling · Salivation · Diarrhea · Sexual arousal suppression · Watery eyes · Motor control enhancement · Yawning · Vomiting · Seizure threshold reduction · Bodily dissociation · Tactile hallucination · Phantom limb sensations
Insomnia · Body high · Heart rate perception changes · Physical fatigue · Muscle tension · Bodily lightness · Body schema distortion · Breathing alteration · Laughter fits · Restlessness · Tactile euphoria · Tingling / electric sensations · Vibrations / buzzing · Nausea · Abnormal heartbeat · Excessive sweating · Sexual arousal enhancement · Bodily heaviness · Bodily pressures · Dehydration sensation · Dizziness · Dry mouth · Kundalini-like energy · Nystagmus (eye wobbles) · Increased urination · Involuntary body movements · Bruxism · Headache · Pain enhancement · Respiratory stimulation · Trembling · Salivation · Diarrhea · Sexual arousal suppression · Watery eyes · Motor control enhancement · Yawning · Vomiting · Seizure threshold reduction · Bodily dissociation · Tactile hallucination · Phantom limb sensations
Aesthetic enhancement · Introspection enhancement · Openness enhancement · Thought connectivity · Multiple thought streams · Immersion enhancement · Cognitive euphoria · Thought acceleration · Cognitive flexibility · Increased nature relatedness · Creativity enhancement · Memory suppression · Thought disorganization · Thought loops · Cognitive fatigue · Cognitive impairment · Confusion · Synchronicity · Humor enhancement · Analysis enhancement · Cognitive dysphoria · Focus suppression · Information processing enhancement · Information processing suppression · Memory fragmentation · Memory replays · Focus enhancement · Language enhancement · Motivation enhancement · Language suppression · Motivation suppression · Memory enhancement · Delusions of sobriety · Delusions · Amnesia · Delirium
Thought connectivity · Multiple thought streams · Immersion enhancement · Cognitive euphoria · Thought acceleration · Cognitive flexibility · Increased nature relatedness · Creativity enhancement · Memory suppression · Thought disorganization · Thought loops · Cognitive fatigue · Cognitive impairment · Confusion · Synchronicity · Humor enhancement · Analysis enhancement · Cognitive dysphoria · Focus suppression · Information processing enhancement · Information processing suppression · Memory fragmentation · Memory replays · Focus enhancement · Language enhancement · Motivation enhancement · Language suppression · Motivation suppression · Memory enhancement · Delusions · Amnesia · Delirium
Euphoria · Simultaneous emotions · Anxiety · Catharsis · Dysphoria · Irritability
Dysphoria · Irritability
Social connection · Trust enhancement · Ego inflation · Automaticity · Flow state · Sociability enhancement · Communication enhancement · Communication suppression · Compulsive behavior reduction · Sociability suppression · Social disconnection · Identity alteration · Boundary dissolution · Cognitive disconnection · Ego dissolution · Telepathic feelings
Flow state · Sociability enhancement · Communication enhancement · Communication suppression · Compulsive behavior reduction · Sociability suppression · Social disconnection · Identity alteration · Boundary dissolution · Cognitive disconnection · Ego dissolution · Telepathic feelings
Time cessation
Non-dual awareness · Transpersonal memory access · Voidness · Death-rebirth sequence · Entity contact · Cessation · Near-death experience
Entity contact · Cessation · Near-death experience
Lucid dreaming enhancement · Lucidity enhancement · Mindfulness enhancement · Recursive awareness
Timeline
First alerts emerge as subtle mood shifts, mild stimulation, and a faint sense of perceptual sharpening. The prodrug deacylation step may contribute to variability in onset timing.
Effects build progressively: colours brighten, surfaces begin to drift, and thought patterns become more fluid. Mild nausea and body load may accompany the ascent. Anxiety about the intensifying experience is common.
Maximum intensity: pronounced visual distortions, geometric patterning, time distortion, thought connectivity, and emotional amplification. Ego dissolution may occur at higher doses. The dominant perceptual shift is a sense of fluid, interconnected awareness.
Effects gradually recede in waves rather than linearly. Visual intensity diminishes, cognitive clarity returns, and emotional tone often shifts toward reflective warmth. Residual stimulation and mild visual activity may persist.
Residual mood elevation, enhanced pattern recognition, and mild perceptual sensitivity may persist for hours to a full day. Sleep quality may be reduced on the night following use.
⚠ Do not drive or operate heavy machinery until after a full night of sleep following the experience.
Safety[edit]
- Acute toxicity
- Low
- Chronic toxicity
- Low
- Withdrawal
- None
- Tolerance buildup
- rapid
- Tolerance reset
- 14 days
- Physical
- None
- Psychological
- Negligible
- Compulsive redosing
- Negligible
- Dose escalation
- Negligible
- Cross-tol.
- LSD · psilo · mesc
Toxicity
Acute toxicity
No human fatalities from 1B-LSD have been reported. Computational modeling has estimated a rat oral lethal dose, with predictions suggesting blood toxicity risk among the highest in the N1-acyl series — but these are unvalidated computer predictions only.[17] safety citation needed The active compound LSD has no established lethal dose in humans.[3]
Cardiovascular effects
LSD produces mild-to-moderate increases in heart rate and blood pressure with no abnormal heart rhythm signal identified in controlled studies.[18] No 1B-LSD-specific cardiovascular data exist.
Poisoning and overdose
A documented cluster of poisonings occurred when users accidentally inhaled white powder sold as cocaine — symptoms included perceptual disturbances, rapid heart rate, and agitation, with no fatalities.[19] This illustrates contamination risk rather than the danger of intentional lysergamide use.
Psychological risks
At doses equivalent to 200 µg LSD and above, acute panic and ego dissolution become the primary limiting effects.[4] Pre-existing anxiety and emotional state at the time of use are strong predictors of a difficult experience.[5]
Persistent visual disturbances after the experience ends — geometry, after-images, halos, and trailing effects — are documented with LSD-class substances.[20] This condition, known as Hallucinogen Persisting Perception Disorder (HPPD), can last months to years; adolescent onset has been documented.[21] No 1B-LSD-specific cases have been reported.
Tolerance and dependence
Tolerance develops almost immediately after a single dose. Serotonin receptors in the frontal cortex reduce in number within 24 hours,[22] and this cross-tolerance extends to all serotonergic psychedelics.[22] Community data point to a tolerance half-life of about 6 days, with full reset in roughly 14 days.[23]
Psychedelics do not produce physical dependence or addiction.[3] Rapid tolerance limits compulsive redosing — the same dose taken the next day produces markedly diminished effects. Substance use disorder reports linked to LSD have appeared in pharmacovigilance databases, though their interpretation is methodologically limited.[24]
Drug Interactions
Serotonergic combinations
Combining 1B-LSD with tramadol — which both blocks serotonin reuptake and acts on opioid receptors — creates a dangerous risk of serotonin syndrome.[25][26] safety citation needed Serotonin toxicity means muscle rigidity, high fever, rapid heart rate, and seizures — a potentially life-threatening state that requires emergency care.
CYP2D6 inhibitors
Several common drugs — including fluoxetine, paroxetine, bupropion, and haloperidol — block CYP2D6, the liver enzyme that breaks down LSD.[15] This raises LSD blood levels by roughly 1.4–1.5 times,[27] producing a stronger and longer experience than expected.
SSRIs and antidepressants
Paroxetine increased LSD blood levels while simultaneously reducing anxiety and nausea — higher drug exposure, lower distress.[27] Long-term SSRI use may separately reduce psychedelic effects by lowering serotonin receptor density over time.
Lithium
Lithium combined with LSD-class psychedelics is associated with increased seizure risk in anecdotal reports. safety citation needed No controlled study has confirmed this, but the consistency of reports warrants treating it as a potentially dangerous combination.
Cannabis
Cannabis is anecdotally reported to intensify psychedelic effects, particularly during the offset phase. No controlled study exists. citation needed
Contraindications
8 knownPersonal or family history of psychotic disorders and concurrent lithium use are absolute contraindications. Relative contraindications include bipolar disorder, seizure disorders, pregnancy, tramadol use, and CYP2D6 poor metabolizer status — which substantially increases LSD exposure and may cause unexpectedly prolonged and intense effects.[15] No 1B-LSD-specific contraindication data exist; all are inferred from the LSD evidence base.
Harm Reduction[edit]
Forms & Identification
1B-LSD is distributed exclusively on blotter paper or as small pellets.[23] Visual inspection cannot confirm identity or dose — all N1-acylated LSD derivatives look identical to each other and to LSD itself.
Reagent testing narrows the field but cannot distinguish between members of this series. Quantitative analysis through a drug-checking service is the only reliable method to confirm identity and dose.
Guidelines
- Test every sample with a reagent kit before use. Send samples to a drug-checking service when available.
- Start with a low dose and wait at least 2–3 hours before considering the experience has fully developed — prodrug conversion may slow onset.
- Eat lightly several hours beforehand. Stay hydrated throughout.
- Clear all obligations for the day and the following morning. Residual effects can impair sleep.
- Keep the environment calm. Have water, blankets, familiar music, and a quiet space available.
- Avoid redosing. Tolerance develops almost immediately — a second dose within 24 hours produces markedly reduced effects and extends the experience without proportional benefit.
- Wait a minimum of 14 days between experiences to allow full tolerance reset.
Set & Setting
The psychological environment matters as much as the dose. Pre-existing anxiety, unresolved emotional distress, and unfamiliar or chaotic surroundings are the strongest predictors of difficult experiences.[5]
Choose a safe, comfortable, and familiar location. Begin only when in a stable emotional state. A trusted, sober companion — a sitter — substantially reduces the risk of panic-driven behavior during the extended experience window.
Aftercare & integration. The days following a psychedelic experience often bring lingering emotional sensitivity, altered perspective, and disrupted sleep. These aftereffects are normal and typically resolve within a week.
Journaling or discussing the experience with a trusted person can help process unusual or difficult material. If distressing thoughts, visual disturbances, or depersonalization persist beyond two weeks, consult a mental health professional experienced with psychedelic integration. Allow insights to settle naturally rather than forcing interpretation.
Recovery & Support
Psychedelics do not produce physical dependence, but patterns of repeated use to escape distress or avoid processing difficult emotions warrant attention. If psychedelic use is interfering with daily functioning, relationships, or mental health stability, professional support is appropriate.
Resources include the Fireside Project (62-FIRESIDE / 623-473-7433), MAPS integration therapist directory, and local psychedelic harm reduction organizations. For general substance use support, SAMHSA's helpline (1-800-662-4357) provides free, confidential referrals.
Recovery resources, crisis lines, and support pathways → View all
Emergency Response
Recognizing an emergency
Most difficult psychedelic experiences are distressing but not medically dangerous. Seek immediate help if the person expresses intent to harm themselves or others, loses all contact with reality and cannot be verbally redirected, experiences chest pain or seizure, or shows signs of serotonin syndrome (rigid muscles, high fever, tachycardia) after combining with other serotonergic drugs.
Immediate steps
- 1. Call emergency services if any red flag above is present.
- 2. Move the person to a quiet, low-stimulation environment.
- 3. Speak in calm, simple sentences. Reassure them that the effects are temporary and time-limited.
- 4. Do not physically restrain unless there is immediate danger of self-harm.
- 5. Do not leave them alone.
What to tell the dispatcher
State the substance name (1B-LSD), estimated dose, time of ingestion, and current symptoms. Good Samaritan laws in many jurisdictions protect callers who report a drug-related emergency from prosecution.
Legal Status[edit]
1B-LSD is not scheduled by name under most national controlled substance laws. Its structural relationship to LSD — universally controlled — places it within structural analog or blanket psychoactive substance frameworks in many countries. Germany has explicitly controlled it under novel psychoactive substance legislation since 2019.[10]
| Jurisdiction | Classification | Key provisions |
|---|---|---|
| Germany | Controlled (NpSG) | Prohibited under Neue-psychoaktive-Stoffe-Gesetz since July 18, 2019; production, import to market, trading, and administration prohibited; possession not penalized under NpSG[10] |
| United Kingdom | Illegal (Psychoactive Substances Act 2016) | All psychoactive substances prohibited unless specifically exempted (alcohol, nicotine, caffeine, medicines); no medical exemption for 1B-LSD |
| United States | Unscheduled; Federal Analogue Act applies | Not listed in CSA schedules; as an LSD analog intended for human consumption, treated as Schedule I under the Federal Analogue Act |
| Canada | Unscheduled; analog provisions may apply | Not specifically named in CDSA; structural relationship to LSD (Schedule III) invokes potential analog classification |
| Australia | Prohibited | Lysergamides broadly covered under TGA Standard for the Uniform Scheduling of Medicines and Poisons |
citation needed
Legal status changes frequently. This information is based on web-retrieved sources and general legislative interpretation. Confirm current scheduling against official statutory documents before relying on this information.
Safety[edit]
- Acute toxicity
- Low
- Chronic toxicity
- Low
- Withdrawal
- None
- Tolerance buildup
- rapid
- Tolerance reset
- 14 days
- Physical
- None
- Psychological
- Negligible
- Compulsive redosing
- Negligible
- Dose escalation
- Negligible
- Cross-tol.
- LSD · psilo · mesc
Toxicity
Acute toxicity
No human fatalities from 1B-LSD have been reported, and no animal toxicity data exist. Computational modeling has estimated a rat oral LD₅₀ of 49–85 mg/kg for 1B-LSD, with a 75% predicted probability of blood toxicity — among the highest in the N1-acyl series — though these are unvalidated computational predictions only.[22] safety citation needed
LSD, the active moiety, is generally considered physiologically safe with no established lethal dose in humans.[3]
Cardiovascular effects
LSD produces mild-to-moderate increases in heart rate and blood pressure with no abnormal heart rhythm signal identified in controlled studies.[23] No 1B-LSD-specific cardiovascular data exist.
Poisoning and overdose
A reported cluster of LSD poisonings occurred when users accidentally snorted white powder sold as cocaine — symptoms included perceptual disturbances, agitation, rapid heart rate, and anxiety, with no fatalities.[24] This case highlights the risk of accidental exposure through contamination or mislabeling rather than intentional lysergamide overdose.
Psychological risks
At doses equivalent to 200 µg LSD and above, significant anxiety and ego dissolution emerge as the primary dose-limiting psychological effects.[5] Pre-existing anxiety and mental state at the time of ingestion are significant predictors of adverse outcomes.[6]
Hallucinogen persisting perception disorder (HPPD) — persistent visual disturbances such as geometry, after-images, halos, and trailing phenomena without impaired reality testing — is documented with LSD-class substances. LSD is the most commonly reported cause in published HPPD case series.[25] HPPD can persist for months to years; adolescent onset has been documented.[26] No 1B-LSD-specific HPPD cases have been reported.
Tolerance and dependence
Tolerance develops almost immediately after a single dose through reduction in 5-HT₂A receptor density in the frontal cortex, detectable within 24 hours.[4] Cross-tolerance occurs between serotonergic psychedelics via this shared mechanism.[4] Community data indicate a tolerance half-life of approximately 6 days, with full reset in about 14 days.[13]
Psychedelics are generally considered not to produce physical dependence or addiction.[3] Rapid tolerance itself limits compulsive redosing — the same dose taken the following day produces markedly diminished effects. Substance use disorder reports associated with LSD have appeared in pharmacovigilance databases, though methodological limitations constrain their interpretation.[27]
Drug Interactions
Serotonergic combinations
The primary interaction risk is serotonin syndrome when 1B-LSD is combined with drugs that boost serotonin through complementary mechanisms. Tramadol — which inhibits serotonin reuptake in addition to acting on opioid receptors — poses a dangerous interaction risk.[28] The combination of reuptake inhibitor with direct 5-HT₂A activation creates the multi-mechanism serotonergic load associated with life-threatening serotonin toxicity.[29] safety citation needed
CYP2D6 inhibitors
Strong CYP2D6 inhibitors (fluoxetine, paroxetine, bupropion, haloperidol) increase LSD exposure by 1.4–1.5-fold.[20] CYP2D6 poor metabolizers experience approximately 75% higher LSD exposure with prolonged and intensified effects.[19]
SSRIs and antidepressants
Paroxetine reduced negative subjective effects (anxiety, nausea) while increasing LSD blood levels — a dissociation between higher drug exposure and lower distress.[20] Chronic SSRI use may separately blunt psychedelic effects through long-term 5-HT₂A downregulation.
Lithium
Lithium combined with LSD-class psychedelics is associated with increased seizure risk in anecdotal reports. No controlled study has confirmed this interaction, but the consistency of reports warrants classification as a potentially dangerous combination. safety citation needed
Cannabis
Cannabis is anecdotally reported to intensify psychedelic effects, particularly during the offset phase. No controlled study of this combination exists. citation needed
Contraindications
8 knownAbsolute contraindications include personal or family history of psychotic disorders and concurrent lithium use. Relative contraindications include bipolar disorder, conditions that lower seizure threshold, pregnancy, concurrent use of tramadol or other drugs with serotonin toxicity potential, and CYP2D6 poor metabolizer status — which substantially increases LSD exposure and may cause unexpectedly prolonged and intensified effects.[19] No 1B-LSD-specific contraindication data exist; all are inferred from the LSD evidence base.
Harm Reduction[edit]
Forms & Identification
1B-LSD is distributed exclusively on blotter paper or as small pellets — forms where visual inspection alone cannot confirm identity or dose. All N1-acylated LSD derivatives are visually indistinguishable from each other and from LSD itself, so reagent testing narrows the field but cannot differentiate between members of this series. Quantitative analysis through an energy-control or drug-checking service is the only reliable method to confirm that a sample is 1B-LSD specifically and to verify its dose.
Guidelines
- Test every sample with a reagent kit before use. Send samples to a drug-checking service when available.
- Start with a low dose and wait at least 2–3 hours before considering the experience has fully developed — prodrug conversion may slow onset.
- Eat lightly several hours beforehand. Stay hydrated throughout.
- Clear all obligations for the day and the following morning. Residual effects can impair sleep.
- Keep the environment calm. Have water, blankets, familiar music, and a quiet space available.
- Avoid redosing. Tolerance develops almost immediately — a second dose within 24 hours produces markedly reduced effects and extends the experience without proportional benefit.
- Wait a minimum of 14 days between experiences to allow full tolerance reset.
Set & Setting
The psychological environment matters as much as the dose. Pre-existing anxiety, unresolved emotional distress, and unfamiliar or chaotic surroundings are the strongest predictors of difficult experiences.[6] Choose a safe, comfortable, and familiar location. Begin only when in a stable emotional state. A trusted, sober companion — a "sitter" — substantially reduces the risk of panic-driven behavior during the extended experience window.
Aftercare & integration. The days following a psychedelic experience often carry lingering emotional sensitivity, altered perspective, and disrupted sleep. These aftereffects are normal and typically resolve within a week.
Journaling or discussing the experience with a trusted person can help process unusual or difficult material. If distressing thoughts, visual disturbances, or depersonalization persist beyond two weeks, consult a mental health professional experienced with psychedelic integration. Allow insights to settle naturally rather than forcing interpretation.
Recovery & Support
Psychedelics do not produce physical dependence, but patterns of repeated use to escape distress or avoid processing difficult emotions warrant attention. If psychedelic use is interfering with daily functioning, relationships, or mental health stability, professional support is appropriate.
Resources include the Fireside Project (62-FIRESIDE / 623-473-7433), MAPS integration therapist directory, and local psychedelic harm reduction organizations. For general substance use support, SAMHSA's helpline (1-800-662-4357) provides free, confidential referrals.
Recovery resources, crisis lines, and support pathways → View all
Emergency Response
Recognizing an emergency
Most difficult psychedelic experiences are distressing but not medically dangerous. Seek immediate help if the person expresses intent to harm themselves or others, loses all contact with reality and cannot be verbally redirected, experiences chest pain or seizure, or shows signs of serotonin syndrome (rigid muscles, high fever, tachycardia) after combining with other serotonergic drugs.
Immediate steps
- 1. Call emergency services if any red flag above is present.
- 2. Move the person to a quiet, low-stimulation environment.
- 3. Speak in calm, simple sentences. Reassure them that the effects are temporary and time-limited.
- 4. Do not physically restrain unless there is immediate danger of self-harm.
- 5. Do not leave them alone.
What to tell the dispatcher
State the substance name (1B-LSD), estimated dose, time of ingestion, and current symptoms. Good Samaritan laws in many jurisdictions protect callers who report a drug-related emergency from prosecution.
Legal Status[edit]
1B-LSD occupies an ambiguous international legal position. It is not scheduled by name under most national controlled substances legislation, but its structural relationship to LSD — a universally controlled substance — brings it within the scope of structural analog or blanket psychoactive substance laws in many jurisdictions. As of April 2026, no jurisdiction has scheduled 1B-LSD under traditional controlled substance schedules, though Germany has explicitly controlled it under novel psychoactive substance legislation since 2019.
| Jurisdiction | Classification | Key provisions |
|---|---|---|
| Germany | Controlled (NpSG) | Prohibited under Neue-psychoaktive-Stoffe-Gesetz since July 18, 2019; production, import to market, trading, and administration prohibited; possession not penalized under NpSG[11] |
| United Kingdom | Illegal (Psychoactive Substances Act 2016) | All psychoactive substances prohibited unless specifically exempted (alcohol, nicotine, caffeine, medicines); no medical exemption for 1B-LSD |
| United States | Unscheduled; Federal Analogue Act applies | Not listed in CSA schedules; as an LSD analog intended for human consumption, treated as Schedule I under the Federal Analogue Act |
| Canada | Unscheduled; analog provisions may apply | Not specifically named in CDSA; structural relationship to LSD (Schedule III) invokes potential analog classification |
| Australia | Prohibited | Lysergamides broadly covered under TGA Standard for the Uniform Scheduling of Medicines and Poisons |
citation needed
Legal status is based on web-retrieved sources and general legislative interpretation. Confirm current scheduling against official statutory documents before relying on this information.
Frequently asked questions
How long does 1B-LSD last?
Total duration by route of administration — Oral: 8 – 12 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 1B-LSD?
Psychedex publishes a dosage table for 1B-LSD 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 1B-LSD?
The highest-severity documented interactions for 1B-LSD: MAOIs (Lethal), Buspirone (Dangerous), DXM (Dangerous), GHB, Baclofen (Dangerous), GHB, GBL (Dangerous). See the interactions section for the full list with mechanisms and severity levels.
Is 1B-LSD addictive?
Psychedex records tolerance and dependence data rather than a yes/no rating. Recorded tolerance indicators for 1B-LSD: tolerance builds rapid; full reset takes 14 days; cross-tolerance develops with LSD, psilocybin, mescaline, DMT, DOI, 1P-LSD, ALD-52, 1CP-LSD. See the article's dependence and safety sections for recorded dependence data.
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references
- [1] ^abcHalberstadt AL, Chatha M, Klein AK, McCorvy JD, Meyer MR, Wagmann L, Stratford A, Brandt SD (2020) Pharmacological and biotransformation studies of 1-acyl-substituted derivatives of d-lysergic acid diethylamide (LSD) — Neuropharmacology doi:10.1016/j.neuropharm.2019.107856
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- [4] ^abHolze F, Vizeli P, Müller F, Ley L, Duerig R, Varghese N, Zizzari P, Liechti ME (2021) Acute dose-dependent effects of lysergic acid diethylamide in a double-blind placebo-controlled study in healthy subjects — Neuropsychopharmacology doi:10.1038/s41386-020-00883-6
- [5] ^abcdVizeli P, Studerus E, Holze F, Schmid Y, Dolder PC, Ley L, Straumann I, Becker AM, Müller F, Arikci D, Liechti ME (2024) Pharmacological and non-pharmacological predictors of the LSD experience in healthy participants — Translational Psychiatry doi:10.1038/s41398-024-03074-9
- [6] ^Kavanagh PV, Westphal F, Pulver B, Elliott S, Stratford A (2024) Analytical and behavioral characterization of 1-dodecanoyl-LSD (1DD-LSD) — Drug Testing and Analysis doi:10.1002/dta.3691
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- [4] ^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
- [5] ^abcHolze F, Vizeli P, Müller F, Ley L, Duerig R, Varghese N, Zizzari P, Liechti ME (2021) Acute dose-dependent effects of lysergic acid diethylamide in a double-blind placebo-controlled study in healthy subjects — Neuropsychopharmacology doi:10.1038/s41386-020-00883-6
- [6] ^abcdVizeli P, Studerus E, Holze F, Schmid Y, Dolder PC, Ley L, Straumann I, Becker AM, Müller F, Arikci D, Liechti ME (2024) Pharmacological and non-pharmacological predictors of the LSD experience in healthy participants — Translational Psychiatry doi:10.1038/s41398-024-03074-9