Proscaline
3,5-dimethoxy-4-propoxyphenethylamine
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Proscaline (3,5-dimethoxy-4-propoxyphenethylamine) is a synthetic psychedelic of the phenethylamine class. It is a close structural relative of mescaline, but substantially more potent per milligram.[1] It activates serotonin receptors in the brain, producing the altered perception and emotional shifts characteristic of classical psychedelics.[2]
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Czechoslovakian researchers first tested proscaline at doses up to 80 mg, noting effects lasting beyond 12 hours.[3] Alexander Shulgin independently synthesized it and published detailed self-experiments as entry #140 in PiHKAL (1991).[4] Today it circulates in small quantities among research chemical users and remains unscheduled by name in most countries.
Subjective effects include physical warmth, deep bodily relaxation, euphoria, and emotional contentment. The experience is defined by its somatic quality — sustained bodily ease and emotional equanimity with little visual activity at common doses.[3] At higher doses, warmth can shift into irritability, and residual dream disturbances are reported.
Proscaline does not cause physical dependence; tolerance builds rapidly through serotonin downregulation, making compulsive use self-limiting.[5] The primary risks are psychological — panic, anxiety, and psychosis-like states — amplified by high doses and by combining with monoamine oxidase inhibitors, which can trigger dangerous serotonin overload.[6] Evidence comes almost entirely from one mouse study and Shulgin's self-experiments — human safety data are essentially absent.[1]
History[edit]
Discovery
Czechoslovakian researchers first tested proscaline at doses up to 80 mg, observing effects lasting beyond 12 hours and residual dream disturbances.[3] Their identities remain unrecorded in indexed literature. Alexander Shulgin independently synthesized it and documented it as compound #140 in PiHKAL (1991), describing somatic warmth, euphoria, and minimal visual effects at 30–60 mg.[4][3]
Clinical and cultural significance
The only peer-reviewed study — Halberstadt et al. (2019) — confirmed proscaline is more potent than mescaline and escaline in a mouse behavioral assay.[1] No clinical trials have been conducted and the compound has not entered pharmaceutical development.
Prohibition and modern use
The United Kingdom classified proscaline as a Class A substance under the Misuse of Drugs Act 1971, using a broad clause covering ring-alkoxy phenethylamine derivatives.[7] No other jurisdiction has individually scheduled it by name. Proscaline appeared on research chemical markets during the 2000s–2010s expansion of novel psychoactive substances, though no forensic seizure case reports have been published.
Proscaline takes its name from its position in the "scaline" series — a family of mescaline homologues named by extending the parent compound's suffix. The series is defined by progressive lengthening of mescaline's 4-methoxy group into longer alkoxy chains: Escaline (ethoxy), proscaline (n-propoxy), and isoproscaline (isopropoxy). The naming convention reflects systematic chemical relationship rather than any cultural or traditional identity.
Chemistry[edit]
Structural class
Proscaline belongs to the "scaline" series — a family of mescaline homologues defined by progressively longer alkoxy chains at the 4-position of the ring.
Where escaline carries 4-ethoxy, proscaline carries 4-n-propoxy. The related compound 3C-P shares the same ring substitution but adds a methyl group to the side chain, making it more potent.[8]
Molecular structure
| Molecular formula | C₁₃H₂₁NO₃ |
| Molecular weight | 239.31 g/mol |
Proscaline hydrochloride is a white solid with a melting point of 170–172 °C.[4][3]
Pharmacology[edit]
Mechanism of action
Proscaline activates serotonin receptors in the cortex.[1][9] This is established behaviorally: proscaline reliably produces the mouse head-twitch response, a behavior driven exclusively by serotonin receptor activation and blocked by selective antagonists. Activation of these receptors on deep-layer cortical neurons is the established mechanism for psychedelic effects across this compound class.[2]
No receptor binding data have been published for proscaline — no affinities, potency values, or selectivity profiles. The mechanism is inferred from structural class membership and behavioral assay results.[1]
Pharmacokinetics
No human pharmacokinetic data exist for proscaline. Based on mescaline, the closest well-studied relative, oral absorption peaks around 2 hours, plasma half-life is approximately 3.5 hours, and subjective effects last 6–14 hours depending on dose.[6]inferred The body is expected to break proscaline down through pathways similar to mescaline — including one mediated by the enzyme MAO-A, which is blocked by MAOI drugs, and which would sharply raise proscaline's levels if inhibited.[10][11]inferred
Neuroscience[edit]
Where it acts
Proscaline is expected to engage the same brain circuits as mescaline, psilocybin, and LSD — serotonin receptors concentrated on deep-layer neurons of the prefrontal cortex.[2]inferred Activating these neurons disrupts normal sensory filtering and raises overall brain activity, producing the characteristic altered state.
Why proscaline skews more somatic and less visual than mescaline at standard doses is not known. It may reflect dosing below the visual activation threshold, or a subtly different pattern of brain engagement — no data exists to settle the question.
Why it matters
The leading framework for psychedelic action — REBUS — proposes that these drugs relax the brain's top-down predictions, allowing suppressed sensory and emotional content to surface. Serotonergic psychedelics also promote new connections between brain cells through growth factor signaling. Both ideas are built primarily from LSD and psilocybin data; whether they explain proscaline's somatic-emotional profile is plausible but untested — no direct neuroplasticity data exist for proscaline.
- Does proscaline's somatic, visual-sparse phenomenology reflect a distinctive receptor activation profile, or does it simply reflect insufficient dose relative to the visual threshold?
- Does the 4-propoxy group confer different signaling bias relative to mescaline's 4-methoxy?
- Does proscaline promote structural neuroplasticity, and at what concentrations relative to mescaline?
Subjective Effects[edit]
Proscaline's experience is defined by the body, not the eye. Sustained physical warmth, deep muscle relaxation, and emotional contentment settle in and hold — visual activity is minimal at common doses. Set and setting shape the emotional tone strongly; that warmth can shift toward irritability as dose increases.
Within the scaline family, proscaline sits at roughly 5–10× mescaline's potency by weight but with a qualitatively different character. Where mescaline produces broad visual psychedelia across its active range, proscaline skews toward the somatic and emotional — visuals emerge only at the upper dose boundary.
Effect Grid
At common doses (30–40 mg oral), proscaline's characteristic profile fully manifests: deep contentment, emotional warmth, euphoria, and a somatic quality that distinguishes it from more visually oriented psychedelics. Shulgin described 40 mg as producing "deep feeling of peace and contentment" lasting throughout the day. Cognitive effects include enhanced novelty perception and conceptual thinking, while visual phenomena remain notably mild or absent at this range.
Physically, spontaneous body sensations become more pronounced — warmth, tingling, and a sense of physical well-being. Pupil dilation is expected. Nausea is not prominently reported.
Duration is 8–12 hours. Sleep is unlikely during the active phase. Plan for a full day commitment.
Modeled from the effect's dose-dependence curve — not per-substance measurements.
Symmetrical texture repetition · Brightness alteration · Visual breathing · Music enhancement · Environmental patterning · Depth perception distortion · Perspective distortion · Tracers · After-images · Light sensitivity · Sound sensitivity · Visual morphing · Auditory enhancement · Visual acuity enhancement · Holotropic state · Visual diffraction · Peripheral vision distortion · Proprioceptive distortion · Spatial disorientation · Touch enhancement · Vestibular distortion · Visual haze / noise · Auditory distortion · Auditory misinterpretation · Peripheral misidentification · Synesthesia · Visual melting · Object transformations · Environmental orbism / cubism · Object activation · Visual recursion · Internal hallucinations · External hallucinations · Auditory hallucinations
Environmental patterning · Depth perception distortion · Perspective distortion · Tracers · After-images · Light sensitivity · Sound sensitivity · Visual morphing · Auditory enhancement · Visual acuity enhancement · Holotropic state · Visual diffraction · Peripheral vision distortion · Proprioceptive distortion · Spatial disorientation · Touch enhancement · Vestibular distortion · Visual haze / noise · Auditory distortion · Auditory misinterpretation · Peripheral misidentification · Synesthesia · Visual melting · Object transformations · Environmental orbism / cubism · Object activation · Visual recursion · Internal hallucinations · External hallucinations · Auditory hallucinations
Spontaneous body sensations · Nausea · Dizziness · Insomnia · Stimulation · Tingling / electric sensations · Restlessness · Appetite suppression · Bodily pressures · Dry mouth · Laughter fits · Tactile euphoria · Vibrations / buzzing · Muscle tension · Bodily heaviness · Bodily lightness · Body schema distortion · Breathing alteration · Excessive sweating · Headache · Heart rate perception changes · Vasoconstriction · Nystagmus (eye wobbles) · Abnormal heartbeat · Trembling · Vomiting · Bruxism · Bodily dissociation
Insomnia · Stimulation · Tingling / electric sensations · Restlessness · Appetite suppression · Bodily pressures · Dry mouth · Laughter fits · Tactile euphoria · Vibrations / buzzing · Muscle tension · Bodily heaviness · Bodily lightness · Body schema distortion · Breathing alteration · Excessive sweating · Headache · Heart rate perception changes · Nystagmus (eye wobbles) · Abnormal heartbeat · Trembling · Vomiting · Bruxism · Bodily dissociation
Aesthetic enhancement · Introspection enhancement · Openness enhancement · Thought connectivity · Cognitive euphoria · Immersion enhancement · Cognitive flexibility · Increased nature relatedness · Multiple thought streams · Thought acceleration · Creativity enhancement · Memory suppression · Thought loops · Cognitive impairment · Focus suppression · Analysis enhancement · Humor enhancement · Confusion · Information processing suppression · Memory fragmentation · Synchronicity · Thought disorganization · Delusions
Thought connectivity · Cognitive euphoria · Immersion enhancement · Cognitive flexibility · Increased nature relatedness · Multiple thought streams · Thought acceleration · Creativity enhancement · Memory suppression · Thought loops · Cognitive impairment · Focus suppression · Analysis enhancement · Humor enhancement · Confusion · Information processing suppression · Memory fragmentation · Synchronicity · Thought disorganization
Anxiety · Empathy enhancement · Catharsis · Dysphoria
Derealization · Sociability enhancement · Trust enhancement · Flow state · Boundary dissolution · Identity alteration · Ego dissolution
Boundary dissolution · Identity alteration · Ego dissolution
Recursive awareness
Timeline
First alerts appear as subtle shifts in bodily awareness — a faint tingling, mild sensory sharpening, or gentle warmth. Effects are easily overlooked at lower doses.
Physical and emotional effects build steadily. Somatic warmth deepens, mood elevation becomes distinct, and a growing sense of relaxation or restlessness (variable by individual) develops.
Maximum intensity of somatic and emotional effects. Deep contentment, euphoria, and physical well-being dominate. Visual phenomena remain subdued relative to other phenethylamine psychedelics at common doses.
Effects sustain at a diminished but still present intensity. Emotional warmth and physical relaxation persist. Cognitive clarity typically returns before somatic effects fully resolve.
Gradual return toward baseline. Residual warmth, mild mood elevation, and gentle fatigue are common. Physical effects dissipate before emotional tone fully normalizes.
Residual calm, mild reflectiveness, and possible sleep difficulty persist for several hours after subjective effects resolve. At higher doses (80 mg), dream disturbances may extend into the following night.
⚠ Do not drive or operate heavy machinery for the remainder of the day following ingestion.
Safety[edit]
- Acute toxicity
- Low
- Chronic toxicity
- Negligible
- Withdrawal
- None
- Tolerance buildup
- rapid
- Tolerance reset
- 7 days
- Physical
- None
- Psychological
- Negligible
- Compulsive redosing
- Negligible
- Dose escalation
- Negligible
- Cross-tol.
- LSD · psilo · mesc
Toxicity
No toxicity studies of any kind have been published for proscaline in any species.safety citation needed The mescaline class has a wide safety margin in animal models, but this cannot be applied directly to proscaline, which differs in potency and how it moves through the body. The absence of adverse event reports reflects a data gap, not a demonstrated safety record.
Heart and circulation
Serotonin receptor activation raises heart rate and blood pressure — confirmed for mescaline in controlled human studies.[6] Proscaline is expected to share this cardiovascular profile. No proscaline-specific data exist.
Nausea
Nausea and vomiting are common dose-dependent effects with mescaline.[6] Shulgin's proscaline accounts do not prominently mention nausea,[3] but the sample is far too small to estimate how common it is.
Psychological risks
Anxiety, panic, paranoia, and brief psychosis-like states can occur with any serotonin receptor agonist psychedelic — especially at high doses, in psychologically vulnerable individuals, or in unfavorable settings. Persistent visual disturbances after the experience — HPPD, where visual artifacts outlast the drug — are documented for this compound class;[12] the specific risk for proscaline is unknown.
Tolerance and dependence
Proscaline does not produce physical dependence or a withdrawal. Tolerance develops rapidly through serotonin downregulation, apparent within 24 hours of a single dose.[5]
Full cross-tolerance exists with other serotonergic psychedelics: LSD, psilocybin, Mescaline, and DMT.[5][9] No cross-tolerance occurs with ketamine, MDMA, or cannabinoids.
Drug interactions
All interaction data are inferred from mescaline class pharmacology. MAO inhibitors carry the highest risk — MAO-A normally breaks down phenethylamines, so blocking it with pharmaceutical MAOIs (phenelzine, tranylcypromine, moclobemide) or botanical sources (harmine and harmaline in ayahuasca or Peganum harmala) would sharply increase proscaline's levels and risk dangerous serotonin overload.[10][11]safety citation needed
Lithium combined with serotonergic psychedelics carries seizure risk — this combination is contraindicated.safety citation needed Cannabis intensifies and unpredictably alters the experience, raising anxiety risk. Stimulants (amphetamines, cocaine) add cardiovascular stress on top of proscaline's own effects. 5-HT₂A antagonists (ketanserin, risperidone, clozapine) reduce or block the psychedelic effect.[6]
Contraindications
Personal or family history of psychotic disorders, schizophrenia spectrum conditions, or bipolar I disorder is an absolute contraindication — serotonin receptor activation can trigger or worsen psychotic episodes. Concurrent MAOI use is contraindicated due to serotonin overload risk.safety citation needed Lithium is contraindicated due to seizure risk.safety citation needed
Significant cardiovascular disease — uncontrolled high blood pressure, recent heart attack, serious irregular heartbeat — is a relative contraindication given expected effects on heart rate and blood pressure.[6] Pregnancy is a contraindication; no reproductive safety data exist for proscaline or mescaline.
Harm Reduction[edit]
Forms & Identification
Proscaline circulates primarily as a white crystalline powder (hydrochloride salt), though pressed pills and capsules may appear on research chemical markets. It is visually indistinguishable from dozens of other white-powder phenethylamines, including far more potent compounds from the NBOMe or DOx series.
Reagent testing narrows the field but cannot confirm identity with certainty; laboratory analysis is the only definitive method. Given proscaline's rarity, the risk of receiving a mislabeled substitute is substantial.
Guidelines
- Test every batch with at least two reagent kits before use; do not rely on vendor labeling alone.
- Start at the low end of the reported active range and wait at least 3 hours before considering redosing — onset can be slow and plateau effects may build gradually.
- Eat a light meal 2–3 hours before dosing to reduce nausea risk without slowing absorption excessively.
- Have a sober, trusted companion present for the full duration, particularly for first experiences or unfamiliar batches.
- Prepare the physical environment in advance: comfortable temperature, accessible water and light snacks, minimal stimulation, and a quiet space to retreat to if the experience becomes overwhelming.
- Keep a written note of substance name, dose, and time of ingestion visible — useful for the sitter and essential if emergency services are needed.
Set & Setting
Proscaline's 8–12 hour duration demands deliberate preparation. The full day should be free of obligations — fatigue or time pressure during the extended tail increases the likelihood of anxiety and irritability.
Emotional state before dosing shapes the experience. Proscaline's somatic-emotional character amplifies both positive and negative states: warmth and contentment in favorable conditions, irritability and distress in unfavorable ones. A calm, familiar, private environment with a trusted sober companion is strongly recommended, especially given the compound's limited human data.
Aftercare & integration. The extended duration of proscaline means residual effects — emotional sensitivity, mild fatigue, altered dream patterns — may persist into the following day. Plan for a low-demand recovery day. Sleep may be disrupted the first night; this is expected and typically resolves without intervention.
Journaling or discussing the experience with a trusted person within the first few days helps consolidate insights and process difficult material. If distressing psychological content surfaces during the experience, integration-oriented therapy with a practitioner experienced in psychedelic contexts can be valuable. Persistent anxiety, depersonalization, or visual disturbances beyond a few days warrant professional consultation.
Recovery & Support
Proscaline does not produce physical dependence or withdrawal. However, repeated use of any psychedelic can become a pattern of avoidance or self-medication for underlying psychological distress. If psychedelic use is becoming compulsive, escalating, or interfering with daily functioning, support is available.
Peer support communities, harm reduction organizations, and therapists specializing in psychedelic integration can help. The Fireside Project (62-FIRESIDE / 623-473-7433) offers free peer support for people during or after psychedelic experiences.
Recovery resources, crisis lines, and support pathways → View all
Emergency Response
Recognizing an emergency: Uncomfortable anxiety and transient confusion during a psychedelic experience are distressing but not emergencies. Seek immediate help if any of the following occur: chest pain or pounding heartbeat that does not subside, seizure activity, loss of consciousness, sustained panic with self-harm risk, or complete disconnection from reality with inability to recognize surroundings or people.
Immediate steps:
- Stay with the person. Speak calmly and simply.
- Move them to a quiet, low-stimulation environment if possible.
- If unconscious, place in the recovery position (on their side, airway clear).
- Call emergency services if symptoms are severe, worsening, or involve chest pain, seizure, or loss of consciousness.
- Do not restrain the person unless they are in immediate physical danger.
- Do not induce vomiting.
What to tell the dispatcher: Name the substance (proscaline, a psychedelic phenethylamine), the dose if known, the time of ingestion, and current symptoms. Good Samaritan laws in many jurisdictions protect people who call for help during a drug emergency.
Legal Status[edit]
Proscaline is not individually scheduled by name in most national drug control frameworks, but may be captured by structural analog provisions or generic phenethylamine clauses. Legal status should be verified independently for any specific jurisdiction.
Legal status changes frequently and varies by jurisdiction. This article does not constitute legal advice.
| Jurisdiction | Classification | Key provisions |
|---|---|---|
| United Kingdom | Class A (Schedule 1) | Misuse of Drugs Act 1971, Schedule 2, Part I, paragraph 1(c): generic clause covering phenethylamine derivatives with ring alkoxy substitution[7] |
| United States | Not specifically scheduled (federal) | Mescaline is Schedule I (CSA). Proscaline is not individually listed. The Federal Analogue Act (21 U.S.C. §813) may apply if intended for human consumption, given structural similarity to mescaline |
| Canada | Not specifically scheduled | Mescaline is Schedule III (CDSA). Proscaline is not individually listed in the Controlled Drugs and Substances Act schedules |
| Australia | Uncertain | Mescaline is Schedule 9 (Prohibited Substance) under the Poisons Standard. Proscaline may be covered by analogue provisions but is not explicitly listed |
| Germany | Likely controlled | The Neue-psychoaktive-Stoffe-Gesetz (NpSG, 2016) uses structural analogue definitions that may cover proscaline[13] |
| Switzerland / Austria | Likely controlled | Phenethylamine analog scheduling provisions may capture proscaline under structural definitions[13] |
Analogue act considerations
In the United States, prosecution under the Federal Analogue Act requires demonstrating that proscaline is "substantially similar" in chemical structure and pharmacological effect to a Schedule I or II substance. Proscaline's direct structural derivation from mescaline and its confirmed serotonin receptor activity[1] would likely satisfy both criteria. No published case law specifically addresses proscaline.
references
- [1]
- [2] ^abcNichols DE (2018) Chemistry and Structure-Activity Relationships of Psychedelics. — Current Topics in Behavioral Neurosciences doi:10.1007/7854_2017_475
- [3]
- [4]
- [5] ^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
- [6]