Bioavailability and Acute Effects of Mescaline in Healthy Individuals

Summary description of the study

We investigate the properties and acute consciousness changes of mescaline in healthy subjects. Mescaline occurs naturally in various species of cacti and, like lysergic acid diethylamide (LSD) or psilocybin, belongs to the so-called 'classic psychedelics.' In the current study, we primarily aim to determine what percentage (%) of orally ingested mescaline enters the body. Additionally, we are interested in the general pharmacology (absorption, distribution in the body, excretion via urine), the acute effects triggered by the substance, and the overall tolerability. For this purpose, we will administer mescaline in capsule form for oral intake and as an infusion via the vein on two study days. After administering the substances, you will be repeatedly asked to describe the experienced effects using questionnaires. Blood pressure, pulse, and body temperature will be measured regularly, and blood will be drawn through a venous catheter. The study days will take place at the outpatient research center of the University Hospital Basel and will include an overnight stay (duration of 25 hours each). You will be continuously monitored during the acute effects, and a caregiver will be in the adjacent room at night. The entire study participation lasts 4-8 weeks and includes a screening visit (2 hours), the aforementioned two study days (25 hours), and a final visit (1 hour).

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Intervention under investigation

On the two study days, the following substance combinations will be administered: • A) 500 mg mescaline orally (as capsules for ingestion), as well as a placebo infusion. • B) 200 mg mescaline as an infusion, as well as an oral placebo. All subjects will receive both conditions once, with the order being randomly determined and unknown to both the subject and the supervising person. There must be a minimum interval of 10 days between the study days.

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Disease under investigation

This is not a therapeutic study. This means that no potential healing effects of mescaline are being investigated. The study only includes healthy volunteers.

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Sponsor

Sponsor-Investigator: Dr. med. Lorenz Mueller, MD Division of Clinical Pharmacology and Toxicology University Hospital Basel Schanzenstrasse 55 CH-4031 Basel

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Name of the authorising ethics committee (for multicentre studies, only the lead committee)

Ethics Committee northwest/central Switzerland EKNZ

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Date of authorisation

20.05.2025

(BASEC)

Results of the trial