Fly Agaric

Metadata

Regulatory Status

United States

• DEA Schedule: Amanita muscaria, muscimol, and ibotenic acid are not scheduled under the federal Controlled Substances Act. This is a critical regulatory distinction from psilocybin-containing mushrooms.
• FDA status: Not approved for any therapeutic use. The FDA has deemed A. muscaria and its constituents unapproved for conventional foods and is evaluating their status in dietary supplements. As of 2024-2025, the FDA has issued warning letters to companies marketing A. muscaria products with therapeutic claims.
• Commercial availability: A. muscaria products (dried caps, tinctures, gummies, capsules) are widely sold online and in some retail stores in the US, exploiting the unscheduled status. This has prompted public health concern from the FDA and poison control centers.
• State-level regulation: Louisiana has specifically banned A. muscaria. Some states are considering regulation in response to increasing commercial sales and poisoning reports.

European Union

• Status: Not uniformly regulated across the EU. Legal in most member states for possession but not marketed as a food or dietary supplement. The European Food Safety Authority (EFSA) has flagged A. muscaria as an emerging risk due to increasing availability and consumption.
• Netherlands: Legal for purchase and possession.
• Romania, Hungary, Lithuania: Increasing reports of intentional consumption and associated poisoning cases.

Russia and Former Soviet States

• Status: Long cultural history of use, particularly in Siberia and Kamchatka. Not formally regulated as a controlled substance. Widely available in folk medicine markets.

Japan

• Status: Not specifically controlled. Recognized in Japanese mycological and cultural traditions (tengu mythology).

Australia

• Status: Listed as a poisonous plant/fungus. Not approved for any therapeutic use.

Conditions & Indications

Primary: No Clinically Validated Indications

• Important disclaimer: There are no clinically validated therapeutic indications for Amanita muscaria or its constituents in human medicine. The following sections describe traditional uses, anecdotal claims, and preclinical research, none of which constitute evidence-based medical recommendations.

Traditional/Ethnomycological Uses

• Siberian shamanic practice: The best-documented traditional use is among paleo-Siberian peoples (Chukchi, Koryak, Kamchadal/Itelmen) of eastern Siberia, where A. muscaria served for centuries or millennia as an entheogenic inebriant for shamanic journeys. It was the only intoxicant available before Russian contact brought alcohol. Shamans consumed dried caps to achieve trance states believed to facilitate communication with spirits and out-of-body travel.
• Northern European folk medicine: Historical use as an analgesic (topical application for joint pain), anxiolytic, and sleep aid in Scandinavian and Baltic folk traditions. [UNCERTAIN]
• Insecticide: The common name “fly agaric” derives from the traditional practice of placing caps in milk to attract and kill flies, attributed to ibotenic acid and muscimol content.

Contemporary Anecdotal Uses (Unvalidated)

• Microdosing: Growing trend of consuming sub-perceptual doses (typically 0.5—1 g dried cap) for claimed anxiolytic, mood-enhancing, and sleep-improving effects. No controlled clinical trials support these claims. A small number of uncontrolled observational reports exist.
• Pain management: Anecdotal reports of topical and oral use for musculoskeletal pain. No clinical evidence.
• Alcohol cessation: Folk claims of A. muscaria aiding alcohol cessation, possibly related to its historical role as an alcohol substitute in Siberian cultures. No clinical evidence.

Emerging/Preclinical

• Muscimol as pharmacological tool: Muscimol is widely used in neuroscience research as a selective GABA-A receptor agonist for reversible neuronal inactivation studies. This research use has generated extensive data on GABA-A receptor pharmacology but is not directed at therapeutic development.
• Neuroprotective potential: [NEEDS-RESEARCH] Some preliminary preclinical data suggest muscimol may have neuroprotective properties at low doses through GABA-A receptor activation, but this has not been systematically explored for therapeutic applications.
• Anti-inflammatory compounds: Preliminary in vitro studies suggest A. muscaria extracts contain compounds with anti-inflammatory activity. Mechanisms and specific active compounds are not well characterized.

Mechanism of Action

Primary Mechanisms

1. GABA-A receptor agonism (muscimol): Muscimol is a potent and highly selective agonist at ionotropic GABA-A receptors, binding at the orthosteric GABA binding site on the receptor. GABA-A receptors are the major inhibitory neurotransmitter receptors in the central nervous system, and are ligand-gated chloride ion channels. Muscimol binding opens the chloride channel, hyperpolarizing the postsynaptic neuron and producing neuronal inhibition. This mechanism accounts for the sedative, anxiolytic, muscle-relaxant, and dissociative effects. Muscimol acts on GABA-A receptors in the cerebral cortex, thalamus, hippocampus, and cerebellum, producing a complex pharmacological profile that includes euphoria, dizziness, heightened sensory perception, impaired coordination, and visual disturbances.

2. Glutamate receptor agonism (ibotenic acid): Ibotenic acid is a structural analog of glutamic acid and acts as a non-selective agonist at NMDA and metabotropic glutamate receptors. This excitatory activity produces CNS stimulation and, at high doses, excitotoxic neuronal damage. Ibotenic acid is used in neuroscience as a lesioning agent for selective neuronal ablation. The interplay between the excitatory effects of ibotenic acid and the inhibitory effects of muscimol accounts for the characteristic alternating stimulation/sedation pattern observed in A. muscaria intoxication.

3. In vivo decarboxylation: Ibotenic acid undergoes spontaneous decarboxylation to muscimol both in the mushroom (especially during drying) and in vivo. This conversion is significant because muscimol is approximately 5—10 times more potent than ibotenic acid as a psychoactive agent, while ibotenic acid has greater excitotoxic potential. Traditional preparation methods (drying, heating) promote this conversion, effectively increasing the muscimol:ibotenic acid ratio and potentially improving the safety/efficacy profile.

Secondary Mechanisms

• Muscarinic cholinergic activity: Despite its name, muscarine is present in only trace amounts in A. muscaria (<0.02% dry weight). Muscarine acts as a non-selective agonist at muscarinic acetylcholine receptors, producing parasympathomimetic effects (salivation, lacrimation, gastrointestinal stimulation). At the trace concentrations present, muscarine contributes minimally to the overall pharmacological profile.
• Muscazone: A minor isoxazole derivative formed by UV-mediated rearrangement of ibotenic acid. Weaker CNS activity than muscimol. Pharmacological contribution is considered minor.
• Vanadium accumulation: A. muscaria hyperaccumulates vanadium as the complex amavadin. The biological significance of this vanadium accumulation is unknown, but vanadium compounds have been investigated for insulin-mimetic and potential antidiabetic properties in other contexts. [NEEDS-RESEARCH]

Clinical Evidence Summary

Human Clinical Trials

None. No controlled clinical trials have been conducted with Amanita muscaria, muscimol, or ibotenic acid for any therapeutic indication.

Toxicological Case Series

Pharmacological Research (In Vitro and Animal)

Evidence Limitations

• No clinical trials exist. All human data derives from case reports, poison control databases, and ethnographic accounts. Evidence quality for any therapeutic claim is extremely low.
• Dose-response not characterized in humans. The relationship between A. muscaria dose, muscimol exposure, and clinical outcomes has not been established through systematic pharmacokinetic or pharmacodynamic studies.
• Extreme compositional variability. Muscimol and ibotenic acid concentrations vary enormously between specimens (geography, subspecies, age, season, preparation method), making dosing with whole mushroom material highly unpredictable.
• No standardized preparations. Commercial A. muscaria products (gummies, tinctures, capsules) are not subject to pharmaceutical-grade manufacturing standards and have not been tested for consistency, bioavailability, or safety.
• Publication bias in ethnographic literature. Much of the ethnomycological evidence comes from early ethnographic accounts (18th—19th century) of Siberian shamanic practice, which may reflect observer bias, cultural misinterpretation, or romantic idealization.

Safety Profile

General Assessment

Amanita muscaria is a toxic mushroom that poses significant acute risks, though it is rarely lethal in adults. It is critically important to distinguish A. muscaria (ibotenic acid/muscimol toxidrome) from the deadly amatoxin-containing species A. phalloides (death cap), A. virosa (destroying angel), and A. bisporigera. A. muscaria does not contain amatoxins and does not cause the delayed hepatorenal failure characteristic of those species. The primary toxicity of A. muscaria involves the central nervous system, with a clinical presentation that can include both excitatory and sedative phases.

Contraindications

• CNS depressant medications: Additive sedation with benzodiazepines, barbiturates, opioids, alcohol, and other GABA-ergic agents. Risk of excessive CNS depression, respiratory failure.
• Seizure disorders: Ibotenic acid’s glutamate receptor agonism has excitotoxic and potentially proconvulsant effects at high doses.
• Hepatic/renal impairment: Impaired metabolism and clearance of active compounds.
• Pregnancy and lactation: Ibotenic acid is a known excitotoxin in animal models. Contraindicated due to potential developmental neurotoxicity.
• Children: Higher vulnerability to CNS depression and respiratory compromise due to lower body mass and developing nervous system.
• Psychiatric instability: Dissociative and deliriant effects may exacerbate existing psychiatric conditions.

Drug Interactions

• Benzodiazepines and barbiturates: Both muscimol and benzodiazepines act on GABA-A receptors. Additive or synergistic CNS depression may occur, though they bind at different receptor sites.
• Alcohol: Alcohol potentiates GABA-ergic effects. Combined use increases risk of respiratory depression, aspiration, and injury.
• Opioids: Additive CNS and respiratory depression.
• Anticholinergics: Theoretical additive effects given trace muscarine content, though clinical significance at normal A. muscaria exposure levels is minimal.
• Glutamate receptor modulators: Ibotenic acid’s NMDA agonism could theoretically interact with drugs affecting glutamatergic transmission (e.g., memantine, ketamine).

Side Effects and Toxicity Symptoms

• Onset: 30 minutes to 2 hours after ingestion of fresh or dried fruiting body.
• Phase 1 (stimulation/excitation): Agitation, euphoria, dizziness, heightened sensory perception, visual disturbances, ataxia, myoclonus, hyperkinesis. Duration 1—4 hours.
• Phase 2 (sedation/depression): Deep sedation or sleep, sometimes progressing to obtundation. Duration 2—8 hours.
• Common symptoms: Confusion, disorientation, alternating agitation and somnolence, nausea, vomiting, ataxia, mydriasis, salivation.
• Serious adverse events (rare): Respiratory depression requiring intubation and mechanical ventilation, seizures, severe delirium, aspiration.
• Typical resolution: Most cases resolve within 12—24 hours with supportive care.

Toxicology

• Oral LD50 (mouse): Muscimol: 22 mg/kg; ibotenic acid: 38 mg/kg. Intravenous LD50 of muscimol in rats: 4.5 mg/kg.
• Estimated human lethal dose: Not precisely established. Based on mushroom content and animal data, estimated at approximately 15—20 fresh caps (750 g—1.4 kg fresh weight) for an adult, though individual variation is large. Fatalities in adults are extremely rare and typically involve secondary complications (aspiration, hypothermia, trauma) rather than direct toxicity.
• Pediatric vulnerability: Children are at higher risk due to lower body mass. Fatalities have been reported in children.
• Drying and preparation effects: Traditional drying significantly increases the muscimol:ibotenic acid ratio by promoting decarboxylation. Drying at 60—80 degrees C is reported to be most effective for this conversion. Some traditional preparations involved parboiling (with water discarded) to reduce ibotenic acid content.
• No cumulative organ toxicity has been documented from intermittent use, though long-term safety data from regular consumption are absent.

Clinical Dosage

Important Disclaimer

No evidence-based dosing guidelines exist for Amanita muscaria because no clinical trials have been conducted. The following information is provided for toxicological reference and harm reduction context only, not as therapeutic recommendations.

Ethnographic/Historical Reference Doses

• Traditional Siberian use: 1—3 dried caps consumed by experienced shamans, sometimes with specific preparation (drying, sometimes rehydration in water or reindeer urine, which may further process ibotenic acid to muscimol). Onset 30—60 minutes, effects lasting 4—8 hours.
• Modern self-experimentation (uncontrolled): Reports typically describe 5—10 g dried cap material for psychoactive effects, though extreme variability makes such generalizations unreliable.

Microdosing (Unvalidated)

• Typical claimed dose: 0.5—1.0 g dried cap material, consumed daily or on an alternating schedule.
• Evidence basis: None. No controlled trials, no pharmacokinetic data, no validated dose-response relationship at sub-psychoactive doses.
• Safety concern: Even at low doses, ibotenic acid exposure may carry excitotoxic risk. The muscimol:ibotenic acid ratio varies enormously between specimens, and cumulative effects of chronic low-dose ibotenic acid exposure have not been studied.

Preparation Methods (Toxicological Reference)

• Drying: Reduces ibotenic acid content through decarboxylation to muscimol. Traditional and most common preparation method.
• Boiling/parboiling: Some traditional preparations involve boiling with water discarded to reduce total isoxazole content. Used in some cultures (Japan, parts of Eastern Europe) to prepare A. muscaria as a food after detoxification, though this practice is not recommended.

Sources

• Michelot D, Melendez-Howell LM. Amanita muscaria: chemistry, biology, toxicology, and ethnomycology. Mycol Res. 2003;107(Pt 2):131-146
• Wasson RG. Soma: Divine Mushroom of Immortality. Harcourt, Brace & World; 1968
• Tsujikawa K, Mohri H, Kuwayama K, et al. Analysis of hallucinogenic constituents in Amanita mushrooms circulated in Japan. Forensic Sci Int. 2006;164(2-3):172-178
• Satora L, Pach D, Butryn B, Hydzik P, Balicka-Slusarczyk B. Fly agaric (Amanita muscaria) poisoning, case report and review. Toxicon. 2005;45(7):941-943
• Krogsgaard-Larsen P, Honore T, Hansen JJ, Curtis DR, Lodge D. New class of glutamate agonist structurally related to ibotenic acid. Nature. 1980;284(5751):64-66
• Johnston GA. Muscimol as an ionotropic GABA receptor agonist. Neurochem Res. 2014;39(10):1942-1947
• Ott J. Pharmacotheon: Entheogenic Drugs, Their Plant Sources and History. 2nd ed. Natural Products; 1996
• Feeney K. Revisiting Wasson’s Soma: exploring the effects of preparation on the chemistry of Amanita muscaria. J Psychoactive Drugs. 2010;42(4):499-506
• Rampolli FI, Kamler P, Carnevale Carlino C, Bedussi F. The Deceptive Mushroom: Accidental Amanita muscaria Poisoning. Eur J Case Rep Intern Med. 2021;8(3):002212
• Vendramin A, Brvar M. Amanita muscaria and Amanita pantherina poisoning: Two syndromes. Toxicon. 2014;90:269-272
• Geissler T, Brandt W, Porzel A, et al. Acetylcholine esterase inhibitors — novel facets of the isoxazole class of Amanita muscaria and Amanita pantherina. Fitoterapia. 2010;81(8):1203-1206
• Stebelska K. Fungal hallucinogens psilocin, ibotenic acid, and muscimol: analytical methods and biologic activities. Ther Drug Monit. 2013;35(4):420-442

Connections

• Distinction from serotonergic psychedelics: Amanita muscaria’s pharmacology is fundamentally different from classical psychedelics such as psilocybin (from Psilocybe species). While psilocybin acts primarily as a serotonin 5-HT2A agonist, muscimol is a GABA-A agonist producing sedative-dissociative rather than psychedelic effects. Ibotenic acid adds a glutamatergic excitatory component. The subjective experience — often described as dreamlike, deliriant, and dissociative — differs qualitatively from the perceptual and cognitive alterations of serotonergic psychedelics. This pharmacological distinction is often misunderstood in popular culture, where A. muscaria is erroneously grouped with “magic mushrooms.”
• GABA-ergic mushroom compounds: The GABA-ergic mechanism of muscimol is unique among medicinal mushrooms. While some mushroom species contain compounds that modulate GABAergic neurotransmission indirectly (e.g., Reishi triterpenoids have been reported to potentiate GABA-A receptor activity in vitro), muscimol is a direct and potent GABA-A agonist with a well-characterized binding profile. This makes A. muscaria pharmacologically more comparable to benzodiazepines and barbiturates than to other medicinal mushrooms.
• Neuroprotective vs. neurotoxic compounds: The dual nature of A. muscaria — containing both the potentially neuroprotective muscimol (GABA agonist) and the neurotoxic ibotenic acid (glutamate agonist/excitotoxin) — presents a unique pharmacological challenge. This contrasts with mushrooms like Lion’s Mane, which promotes neuroplasticity through NGF/BDNF stimulation without known neurotoxic components.
• Ethnomycological significance: Among all medicinal and psychoactive mushrooms, A. muscaria holds perhaps the deepest ethnobotanical/ethnomycological history, with documented use spanning millennia in Siberian shamanic traditions and proposed connections to the Vedic soma, Norse berserker rituals, and circumpolar shamanism. This cultural significance is unmatched by other species in this reference, though the historical claims remain contested and difficult to verify.