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Mescaline

A classic psychedelic phenethylamine found in several cacti and central to long-standing ceremonial traditions.

State of the evidence

Synthesized

Synthesized from 10 studies in the library · AI-generated, grounded in the abstracts below

Found by searching the library for Mescaline, peyote, san pedro, huachuma, then ranked by relevance.

Mescaline is a classic serotonergic psychedelic that acts primarily as a 5-HT2A receptor agonist and induces profound alterations in consciousness, emotion, and cognition. Large population studies (n > 130,000) consistently find no association between lifetime mescaline use and mental health problems or suicidal behavior, and long-term religious peyote use shows no psychological or cognitive deficits. However, clinical evidence is weak (no adequate RCTs as of 2026), and mescaline can trigger psychosis in vulnerable individuals, though the magnitude of this risk is not well quantified.

Evidence by study

Direction is which way each study's own result points, not our rating of the study.

What the directions mean
Supports:
the study found the intervention worked, or its hypothesis held.
Opposes:
it found the opposite, no benefit or a harm.
No effect:
no significant difference either way.
Mixed:
effects in both directions within the same study.
Unclear:
the abstract does not report a direction.

Lifetime use of psychedelics (including mescaline) was not associated with increased mental health problems after controlling for confounds.

observational Sample size: 130152

Lifetime use of psychedelics (including mescaline) was not associated with increased serious psychological distress, mental health treatment, suicidal thoughts/plans/attempts, depression, or anxiety.

observational Sample size: 135095

Regular peyote use in a religious setting was not associated with psychological or cognitive deficits compared to minimal substance users.

observational Sample size: 61

Mescaline, like other hallucinogens, involves agonist activity at the serotonin 5-HT2A receptor, which mediates its neuropsychological effects.

theoretical

Potency of hallucinogens (including mescaline) in the mouse head-twitch response assay strongly correlates with human hallucinogenic potency, supporting translational relevance.

preclinical

Psychedelics can exacerbate pre-existing psychotic illness and may trigger psychosis in vulnerable individuals, but the magnitude of risk is inadequately quantified.

review

Lifetime mescaline/peyote use was associated with lower opioid use disorder severity, particularly in those with high mental health impairment.

observational Sample size: 45133

Mescaline produced cerebellar-selective BOLD suppression and global hyperconnectivity, and disrupted sensory processing, distinguishing it from LSD and psilocybin.

preclinical

Unclear

Mescaline is the only phenethylamine classic psychedelic, with the lowest 5-HT2A affinity requiring high doses (hundreds of mg), and clinical evidence is the weakest strand with no adequate RCT as of 2026.

review

Abuse of mescaline and its analogues has shown a gradual increase in recent years, and the paper reviews their pharmacological, toxicological, and detection aspects.

review

Points of agreement

  • Mescaline is a 5-HT2A receptor agonist and a classic psychedelic.
  • Large population studies find no association between lifetime mescaline use and mental health problems.
  • Long-term religious peyote use is not associated with psychological or cognitive deficits.
  • Mescaline can trigger psychosis in vulnerable individuals, but the risk magnitude is not well quantified.

Conflicts

  • One study found mescaline/peyote use associated with lower opioid use disorder severity, while other psychedelics (LSD/psilocybin/MDMA/DMT) were associated with higher severity.
  • Preclinical data show mescaline has distinct neuroimaging effects (cerebellar suppression) compared to LSD and psilocybin, but human comparative data are lacking.

Gaps

  • No adequate randomized controlled trials on mescaline exist as of 2026.
  • The risk of psychosis in vulnerable individuals is not adequately quantified.
  • Durability of effects and long-term outcomes beyond 12 months are not studied.
  • Most studies rely on self-report or observational designs; blinding is difficult.
  • Comparative studies between mescaline and other psychedelics in humans are lacking.
  • Dose-response relationships and optimal therapeutic dosing are not established.
Browse these studies in the library
How we analyze this

This synthesis reads the 15 most-cited and 10 most recent studies whose primary subject is Mescaline, up to 25 in all. The most-cited set anchors the established evidence, and the recent set surfaces work that is too new to have gathered citations yet.

A study qualifies only when Mescaline or a known alias appears in its title or keywords, so broad reviews that mention it only in passing are left out. Each study is read from its abstract, strongest evidence first, and the summary reports the direction of the results along with any conflicts and gaps.

1,033 articles · 162 from the last two years · 4,385,752 participants across 154 studies reporting sample size

Common study designs

review 176 systematic review 33 experimental study 108 historical analysis 60 theoretical or philosophical paper 78

magnetismo del peyote

Revista de Arqueología Americana July 10, 2026 Stacy B. Schaefer

Peyote (Lophophora williamsii) is a psychoactive cactus central to religious beliefs, healing practices, and transformative experiences among Indigenous peoples of Mexico and North America. The Wixárika (Huichol) have the longest known continuous use, while the Native American Church's practices in the US and parts of Canada developed more recently. This article reviews peyote's botany, chemistry, medicinal qualities, ecology, archaeology, history, and religious practices, presenting Indigenous knowledge, rituals, and adaptation to change. It concludes by discussing the alarming scarcity of peyote and conservation efforts to protect the plant's future.

Der gezüchtete psychoaktive Pilz als Fall der Zugangs-Reorganisation — mit dem komparativen Fall des Peyote.** Transdisziplinäre Monografie (Ausbaustufe). Zweisprachig **DE + EN**

Zenodo (CERN European Organization for Nuclear Research) July 1, 2026 Schüller Thomas

A transdisciplinary monograph examines the cultivated psychoactive mushroom as a case of access reorganization, comparing it with peyote. The work argues that the regulation and cultural framing of these substances reshape who can access them and under what conditions, thereby reorganizing social and legal boundaries. The analysis draws on psychoanalysis and social critique to explore themes of closure, the fall of man, and therapeutic applications. The author presents this as a theoretical and philosophical paper, not an empirical study, and offers a bilingual (German and English) account funded privately and licensed under Creative Commons.

Meskalin / Mescaline

Zenodo (CERN European Organization for Nuclear Research) July 1, 2026 Schüller Thomas

Mescaline is the only phenethylamine among the classic psychedelics, with the lowest affinity for the 5-HT2A receptor, requiring the highest doses (hundreds of milligrams) and producing a dose-dependent duration of 6.4 to 14 hours. Clinical research is the weakest strand: as of 2026, no adequate randomized controlled trial exists. In the ecologically bound case of peyote, the logic of dispossession reverses compared to synthetic substances like LSD and psilocybin. The work elevates Discipline 8 (Law/Society) to address peyote conservation (IUCN 'vulnerable') and Indigenous rights (Native American Church, AIRFA 1994) as a standalone discipline.

NOVEL STRUCTURAL HYBRIDS OF MESCALINE WITH PCP-ANALOGS: POTENTIAL ANTAGONISTS FOR CENTRAL PCP-RECEPTORS

Bulletin of Pharmaceutical Sciences. Assiut University May 26, 2026 R. Shafik, N. Eshba, M. El-Semary et al.

Researchers designed new chemical compounds that combine features of mescaline and phencyclidine (PCP) to explore their potential interaction with PCP receptors in rat brains. The proposed molecules are structural hybrids, including variants with an N-(2-chloroethyl) group that could allow them to bind permanently to receptors. However, the actual effects of mescaline and the potential blocking activity of these new compounds at central PCP receptors have not yet been tested.

Mescaline Alters Cerebellar Function, Global Connectivity, and Frequency-Selective Acoustic Gating: A BOLD fMRI Study in Awake Rats.

Neuroscience Bulletin May 21, 2026 Noah Cavallaro, Priya Rai, David Akins et al.

Mescaline, a psychedelic used ceremonially for thousands of years, produces distinct brain effects that differ from LSD and psilocybin. In awake rats, mescaline suppressed BOLD signal in the cerebellum, suggesting it disconnects this region from forebrain areas. However, resting-state scans showed the cerebellum became hyperconnected to the hippocampus, thalamus, somatosensory cortex, and midbrain. Mescaline also eliminated normal brain responses to rewarding smells, indicating disrupted sensory processing. Acoustic startle tests revealed frequency-dependent effects: enhancement at 4 kHz (+27.6%) and 20 kHz (+27.3%), but impairment at 12 kHz (-16.4%). The cerebellum may act as a dysregulated sensory filter, flooding forebrain circuits with unprocessed information, potentially explaining psychedelic-induced perceptual changes.

[Research Progress on Mescaline and Its Analogues].

Fa yi xue za zhi April 25, 2026 Ruidi Shen, Zhenhua Qian

Abuse of mescaline and its analogues, a class of phenethylamine compounds often overlooked, has gradually increased worldwide. This review covers their basic information, pharmacological and toxicological properties, and detection methods, aiming to guide future research and provide references for forensic examination involving these substances.

The Ethnopharmacological Use of Mescaline for Psychiatric Disorders: A Systematic Review

International Journal of Molecular Sciences March 28, 2026 Jonathan Shaw, Aidan Yong, Jacky Lee et al.

Mescaline, the main active compound in Peyote and San Pedro cactus, has a long history in traditional medicine and is gaining renewed clinical interest. A systematic review of 2770 references found only 10 studies suitable for analysis. Reported therapeutic effects included improvements in depression, well-being, nicotine dependence, alcohol use, and obsessions. Bayesian analysis showed frequently reported side effects like hypertension, headache, nausea, and vomiting. The existing literature is limited and highly variable, preventing firm conclusions about mescaline's psychological and somatic effects. More research is needed on its safety. Collaboration between the Native American Church and hospitals is recommended to create a registry for standardized data collection on mescaline's effects in prevalent populations.

Psychedelic Therapy: A Primer for Primary Care Clinicians—Mescaline

February 28, 2026 Burton J. Tabaac, Kenneth Shinozuka, Fadel et al. preprint

Mescaline, a classic serotonergic psychedelic used ceremonially by Indigenous peoples, shows preliminary safety in healthy humans under controlled conditions, producing dose-dependent subjective effects with moderate, transient autonomic stimulation and no serious medical complications. Adverse effects are generally self-limited, and pooled safety analyses and observational data support an overall favorable safety profile in screened populations. However, there is a lack of controlled clinical trials evaluating mescaline in patient populations, so its safety in individuals with cardiovascular, metabolic, or psychiatric comorbidities remains unclear. Controlled clinical trials are needed to establish its safety and therapeutic potential.

Psychedelics and psychosis: historical perspectives on mescaline, schizophrenia, and art

Zenodo (CERN European Organization for Nuclear Research) January 28, 2026 Irina Terekhova

Since the mid-nineteenth century, scientists have considered psychedelics as models for psychosis, with early twentieth-century experiments testing this idea. Debate continues over whether certain drugs specifically induce schizophrenia-like states. Early mescaline research at prominent institutions, inspired by Hans Prinzhorn's work on 'schizophrenic masters,' included 1938 experiments by psychiatrists Eric Guttmann and Walter Maclay, who took the drug and had artists depict their altered perceptions. In the 1950s, mescaline was used to study schizophrenia. Henri Michaux, under clinical supervision, produced writings and drawings from mescaline experiences that resembled but differed significantly from schizophrenic creative outputs. This historical analysis highlights differences in lived experiences and artistic expressions between schizophrenia and mescaline-induced states.

The first applications of mescaline in psychiatry: The case of Madame Louise Françoise R. and its contemporary relevance

Neuropharmacology October 15, 2025 Marion Hendrickx, Antoine Dampierre, Emmanuel Drouin 1 citation

In 1930, four years before their official publication, psychiatrists Henri Claude and Henri Ey treated a patient, Madame Louise Françoise R., with mescaline at Sainte-Anne hospital in Paris. They administered subcutaneous injections of 20-40 mg, doses now considered sub-threshold, far below the later recognized effective range of 250-500 mg. The experiment was exploratory, using mescaline as a functional probe to observe psychopathological mechanisms rather than as a cure. The patient experienced colored visions, depersonalization, and the observation that "mescaline releases but does not create fantasies." A few days later, she received malariotherapy, an archetypal shock therapy, which was followed by clinical improvement.

Clinical trials

All Mescaline trials →