Acute Effects of Intravenous 5-MeO-DMT in Healthy Participants (MEOS)

Acute Subjective Effects, Physiological Effects, and Pharmacokinetics of Intravenous 5-MeO-DMT Infusions in a Double-blind, Placebo-controlled, Single Ascending Dose Study in Healthy Participants

Participation in this study lasts approximately two weeks and includes three on-site study visits: a screening visit (approximately 2 hours), a study drug administration visit (approximately 4 hours), and a follow-up visit approximately one week later (approximately 2 hours).

If participants decide to take part in the study and meet the inclusion and exclusion criteria, they will be randomly assigned to one of two groups: an experimental group or a control group. Participants will not be informed of your group assignment. Participants in the experimental group will receive the investigational substance 5-MeO-DMT at a dose of 0.2, 0.4, 0.6, or 0.8 mg/min for a total infusion duration of 30 min. Participants in the control group will receive a placebo that is indistinguishable in appearance from the investigational substance. Following substance administration, participants will be repeatedly asked to describe their subjective experiences. Blood pressure and heart rate will be monitored regularly, and blood samples will be collected via an intravenous catheter.

Study Overview

• Status: Recruiting
• Conditions: 5-methoxy-dimethyltryptamine (5-MeO-DMT)
• Intervention / Treatment: Drug: 0.2 mg/min 5-MeO-DMT; Drug: Placebo; Drug: 0.4 mg/min 5-MeO-DMT; Drug: 0.6 mg/min 5-MeO-DMT; Drug: 0.8 mg/min 5-MeO-DMT

• Study Type: Interventional
• Enrollment (Estimated): 40
• Phase: Phase 1

Contacts and Locations

• Study Contact: Name: Livio Erne, MSc Drug Sciences; Phone Number: +41613284818; Email: livio.erne@usb.ch
• Study Contact Backup: Name: Severin B Vogt, Dr. med.; Phone Number: +41 61 328 68 66; Email: severinbenjamin.vogt@usb.ch

Study Locations

• Switzerland
  • Canton of Basel-City
    • Basel, Canton of Basel-City, Switzerland, 4056
      • Recruiting
      • University Hospital Basel
      • Contact: Livio Erme, MSc Drug Sciences; Phone Number: +41 61 328 48 18; Email: livio.erne@usb.ch
      • Contact: Severin Vogt, Dr. med.; Phone Number: +41 61 328 68 66; Email: severinbenjamin.vogt@usb.ch

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

1. Age between 25 and 65 years old
2. Sufficient understanding of the German language
3. Understanding of procedures and risks associated with the study
4. Willing to adhere to the protocol and signing of the consent form
5. Willing to refrain from the consumption of illicit psychoactive substances during the study
6. Willing not to operate heavy machinery for 48 hours after the study session.
7. Willing to use effective birth control throughout study participation
8. Body mass index between 18-29 kg/m2

Exclusion Criteria:

1. Chronic or acute medical condition
2. Current or previous major psychiatric disorder
3. Psychotic disorder or bipolar disorder in first-degree relatives
4. Hypertension (SBP>140/90 mmHg) or hypotension (SBP<85 mmHg)
5. Hallucinogenic and/or dissociative substance use (not including cannabis) more than 20 times or any time within the previous two months
6. Pregnancy or current breastfeeding
7. Participation in another clinical trial (currently or within the last 30 days)
8. Use of medication that may interfere with the effects of the study medication
9. Tobacco smoking (>10 cigarettes/day)
10. Consumption of alcoholic beverages (>15 drinks or >180g alcohol per week)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

5

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: 0.2 mg/min 5-MeO-DMT; 0.2 mg/min 5-MeO-DMT will be administered intravenously for a total infusion duration of 30 min.	Drug: 0.2 mg/min 5-MeO-DMT; 0.2 mg/min 5-MeO-DMT will be administered intravenously for a total infusion duration of 30 min.
Placebo Comparator: Placebo; Placebo (saline) will be administered for a total infusion duration of 30 min.	Drug: Placebo; Placebo (saline) is administered for a total infusion duration of 30 min.
Experimental: 0.4 mg/min 5-MeO-DMT; 0.4 mg/min 5-MeO-DMT will be administered intravenously for a total infusion duration of 30 min.	Drug: 0.4 mg/min 5-MeO-DMT; 0.4 mg/min 5-MeO-DMT will be administered intravenously for a total infusion duration of 30 min.
Experimental: 0.6 mg/min 5-MeO-DMT; 0.6 mg/min 5-MeO-DMT will be administered intravenously for a total infusion duration of 30 min.	Drug: 0.6 mg/min 5-MeO-DMT; 0.6 mg/min 5-MeO-DMT will be administered intravenously for a total infusion duration of 30 min.
Experimental: 0.8 mg/min 5-MeO-DMT; 0.8 mg/min 5-MeO-DMT will be administered intravenously for a total infusion duration of 30 min.	Drug: 0.8 mg/min 5-MeO-DMT; 0.8 mg/min 5-MeO-DMT will be administered intravenously for a total infusion duration of 30 min.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in subjective effects over time (assessed with subjective effect scales (SES))	Participants will be asked by the investigator to repeatedly rate their subjective effects verbally on a Likert scale from 0 to 10 for: "any drug effect", "good drug effect", "bad drug effect", and "fear". Ratings will be performed before and repeatedly after substance administration and will take approximately 30 sec to complete.	Up to 245 minutes at the substance administration session (Session 2): 1 hour and 5 minutes before and 5, 10, 15, 20, 30, 35, 40, 50, 60, 75, 90, 120, 150, 180 min after substance administration.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Treatment-emergent adverse events (TEAEs)	A TEAE is an adverse event (AE) that emerges during treatment (having been absent before treatment) or that worsens after treatment. Spontaneously reported AEs, AEs in response to questioning or observed AEs by the investigators will be recorded at the substance administration session (Session 2) and at the end of study visit (EOS, Session 3). Clinically significant abnormalities in the results of a laboratory test, on the ECG or on suicidal ideation (C-SSRS) may also be recorded as TEAE. TEAEs will be summarized and tabulated by treatment (5-MeO-DMT vs. placebo).	Up to one week (from substance administration session (Session 2) to end of study visit (EOS, Session 3))
Change in Safety lab parameters	A routine safety laboratory blood test is performed at the screening (Session 1) and at the end of study visit (Session 3) including creatinine, alanine aminotransferase (ALAT), aspartate transaminase (ASAT), hemoglobin, hematocrit, white blood cell count, red blood cell count, and platelet cell count (total of 7.3 ml blood).	Up to 14 days (from Screening (Session 1) until end-of-study-visit (EOS, Session 3))
Change in Vital Signs	Blood pressure, heart rate, and body temperature will be recorded at baseline and repeatedly throughout the drug administration session (Session 2). Blood pressure (systolic and diastolic) and heart rate will be measured with an automatic oscillometric device. Measurements will be taken in supine position. For blood pressure, duplicate measurements will be performed.	Up to 245 minutes at the substance administration session (Session 2): 1 hour and 5 minutes before and 5, 10, 15, 20, 30, 35, 40, 50, 60, 75, 90, 120, 150, 180 min after substance administration.
Change in Adverse effects list (Beschwerdenliste (BL-R)	The Adverse effects list (= Beschwerdenliste) is a self-reporting tool to assess physical and general discomfort. We will use the 2011 revised version, which consists of a 40-item list to assess physiological complaints throughout the study sessions. The BL-R covers a wide variety of symptoms and complaints that are answered with a four-point Likert scale ranging from "not at all" to "strong". We added several items that have been frequently observed in previous research with psychedelics by the several research groups. The scale will be administered at baseline and at the end of the substance administration session (Session 2).	Up to 4 hours at substance administration session (Session 2) (at baseline and after substance administration)
Swiss Psychedelic Side Effects Inventory (SPSI)	The Swiss Psychedelic Side Effects Inventory (SPSI) has recently been developed and validated by an expert panel, leveraging insights from previous research to enhance the assessment of clinically relevant side effects in studies of psychedelic-assisted therapy. The SPSI assesses 32 potential side effects, along with standardized follow-up questions about their severity, impact, treatment-relatedness, and duration. The scale provides total scores for the number, severity, and impact of side effects, as well as an overall score representing the burden of side effects within a specified timeframe. The scale will be administered at the end of study visit (EOS, Session 3).	One time assessment at End-of-study-visit (EOS, Session 3 = 7 days after substance administration)
Change in Columbia-Suicide-Severity-Rating-Scale (C-SSRS)	The C-SSRS is a suicide risk assessment tool that assesses suicidal ideation and behavior and has repeatedly been shown to accurately predict suicide risks across different populations. The C-SSRS includes the two main domains suicidal ideation and suicidal behaviour. The suicidal ideation domain will be rated based on "Yes"/"No" responses to each of the following types of ideation: 1) wish to be dead, 2) non-specific ideal active suicidal thoughts, 3) active suicidal ideation with any methods (no plan) without intent to act, 4) active suicidal ideation with some intent to act without a specific plan, and 5) active suicidal ideation with a specific plan and intent. The highest numbered item rated "yes" will be scored to assess the suicidal ideation score. If suicidal ideation is present, the intensity of suicidal ideation will be measured (frequency, duration, controllability, deterrents, and reasons for suicidal ideation).	Up to 14 days (from Screening (Session 1) to Substance administration session (Session 2) until End-of-study-visit (EOS, Session 3))
5-Dimensions of Altered States of Consciousness Scale (5D-ASC)	Visual analog scale consisting of 94 items. Constructed of five scales and allows assessing mood, anxiety, derealization, depersonalization, changes in perception, auditory alterations, and reduced vigilance. Scales will be presented as 100 mm long horizontal lines marked with vertical lines by the participant.	One time assessment at substance administration session (Session 2): 3 hours after substance administration
States of Consciousness Questionnaire (SCQ)	The States of Consciousness Questionnaire has been widely used in clinical trials with psychedelics to assess changes in perception, moods, thought, and self-awareness, with a focus on spiritual or mystical-type experiences. The original SCQ comprises 100 items rated on a six-point scale. The SCQ will be analyzed using the psychedelic experience scale (PES48). The PES48 is a revised and psychometrically validated factor structure derived from the SCQ, consisting of 48 of its 100 items. In addition to the four core dimensions measured by the Mystical Experience Questionnaire (MEQ30/MEQ43)--Mystical Experience, Positive Mood, Transcendence of Time and Space, and Ineffability-the PES48 includes four additional subscales: Paradoxicality, Connectedness, Visual Experiences, and Distressing Experience. Data on each domain scale will be expressed as a percentage of the maximum possible score.	One time assessment at substance administration session (Session 2): 3 hours after substance administration
Ego dissolution inventory (EDI)	The Ego Dissolution Inventory (EDI) is an 8-item self-report questionnaire originally developed and validated in English to assess transient alterations in self-experience during psychedelic states. The scale measures the extent of ego dissolution, i.e., the subjective loss of one's sense of self and boundaries between self and environment, which represents a core feature of the psychedelic experience. A German translation and psychometric validated version of the EDI is used.	One time assessment at substance administration session (Session 2): 3 hours after substance administration
Near-death experience content scale (NDE-C)	The Near-Death Experience Content (NDE-C) scale is a modified version of the NDE-scale. It assesses 20 items rated on a 5-point Likert scale. It is a tool to assess dimensions of near-death experience and has been psychometrically validated. We will use a slightly modified, non-validated version translated into German language. Specifically, we added six new items assessing dimensions of fear, non-existence, loneliness, void, and borderline experience in more detail. The scale will be administered once, 3 h after drug administration and subjects.	One time assessment at substance administration session (Session 2): 3 hours after substance administration
Emotional Breakthrough Inventory Plus (EBI+)	The Emotional Breakthrough Inventory Plus (EBI+) contains all six items of the EBI, plus 12 additional items (i.e., 18 items in total) developed by the psychologist and linguist K. Stocker (University Hospital Basel/University Basel and ETH Zurich). The 6-item Emotional Breakthrough Inventory (EBI) is a reliable and validated measure of cathartic release and resolution of difficult emotions or trauma following a psychedelic experience. Completion of the EBI+ will take around 10 to 15 minutes.	One time assessment at substance administration session (Session 2): 3 hours after substance administration
PAE-PS-ext (PAE-PS-ext)	This questionnaire rates psychedelic experiences with a focus on phenomenological, autobiographical, and existential psychedelic experiences. The scale includes 12 main questions to be answered on a total of 78 sub-ordered visual rating scales (sub-ordered visual rating scales mostly only need to be answered when the answer to the main question is "yes"). The last major question with eight sub-ordered visual rating scales of the PAE-PS is on worldview/beliefs.	One time assessment at substance administration session (Session 2): 3 hours after substance administration.
Change in Endocrine lab parameters	Blood samples to assess endocrine effects (prolactin, cortisol, oxytocin) of 5-MeO-DMT will be collected before and after substance administration.	Up to 180 minutes at substance administration session (Session 2): 30 and 180 minutes after substance administration.
Change in Substance plasma concentration	Plasma concentration of 5-MeO-DMT and Metabolites after substance administration. Calculated via blood samples.	Up to 245 minutes at the substance administration session (Session 2): 1 hour and 5 minutes before and 5, 10, 15, 20, 30, 35, 40, 50, 60, 75, 90, 120, 150, 180 min after substance administration.
Freiburger Personality Inventory (FPI)	The FPI is a well-validated psychological personality questionnaire, widely used in psychological research and for diagnostic purposes. It comprises 138 items compiled into 10 scales for the assessment and scoring of the following personality traits: life satisfaction, social orientation, achievement orientation, inhibitedness, excitability, aggressiveness, strain, physical complaints, health concern, frankness, extraversion, emotionality. The FPI will be completed once.	One time assessment at Screening (Session 1 = up to 2 hours)
NEO Five Factor Inventory (NEO-FFI)	The NEO Five-Factor Inventory (NEO-FFI) is a multidimensional personality inventory, comprising 60 items. It evaluates the "BIG 5" personality traits: Neuroticism, Extraversion, Openness, Agreeableness, and Conscientiousness. The NEO-FFI will be completed once.	One time assessment at Screening (Session 1 = up to 2 hours)
Connor-Davidson Resilience Scale (CD-RISC)	Trait resilience will be assessed using the Connor-Davidson Resilience Scale (CD-RISC). A previously validated german version of the CD-RISC-10, containing 10 items, will be used.	One time assessment at Screening (Session 1 = up to 2 hours)
ABC Connectedness to Nature Scale (ABC-CNS)	Trait connection to nature will be explored using the ABC connectedness to nature scale (ABC-CNS). The questionnaire is partly based on a previous scale named the Connectedness to nature scale. We translated the questionnaire into german language.	One time assessment at Screening (Session 1 = up to 2 hours)
Change in Appreciation Scale (AS)	The Appreciation Scale (AS) comprises 57 self-rating items measuring eight aspects of appreciation, i.e. "Have focus", "Awe", "Ritual", "Present Moment", "Self/Social Comparison", "Gratitude", "Loss/Adversity", and "Interpersonal". Subjects are asked to rate the statements on a scale from 1 to 7 in terms of either attitude intensity ('strongly disagree' to 'strongly agree') or frequency ('never' to 'more than once a day'). Scores on the subscales can be summed up to yield a score representing the overall degree of appreciation (or level of appreciativeness), with higher scores indicating higher appreciation levels. The questions will be administered twice.	Up to 14 days (from Screening (Session 1) to End-of-study -visit (EOS, Session 3))
Change in Scale of Positive and Negative Experience (SPANE)	The Scale of Positive and Negative Experience (SPANE) is a 12-item questionnaire to capture the affective component of subjective well-being. It reflects a person's balance between pleasant and unpleasant affect in life. The SPANE includes six items to assess positive feelings and six items to assess negative feelings. The feelings are reported on a 5-point scale ranging from 'very rarely' to 'very often or always'. The SPANE provides an overall affect balance score and may be divided into positive/negative feelings scales. The scale will be administered three times.	Up to 14 days (from Screening (Session 1) to Drug administration session (Session 2) until end-of-study-visit (EOS, Session 3))
Change in Global Life Satisfaction (GLS)	Global life satisfaction is assessed based on a single item life satisfaction measure which is a simple, yet widespread approach. The specific wording of the question is adopted from the Swiss household panel study which is a representative survey of the Swiss population. The question can be answered on a 11-point scale: "In general, how satisfied are you with your life if 0 means 'not at all satisfied' and 10 means 'completely satisfied'?". The question will be administered three times.	Up to 14 days (from Screening (Session 1) to Drug administration session (Session 2) until end-of-study-visit (EOS, Session 3))
Change in Credibility/Expectancy Questionnaire (CEQ)	The CEQ is a validated instrument designed to assess participants' beliefs about the credibility of the treatment and their expectations for improvement. Since the original questionnaire is intended for clinical trials involving patients, it has been adapted for the specific context of this study in healthy participants. Four items will be used to assess expectations regarding the psychoactive effects of 5-MeO-DMT: 1. How strongly do you expect to feel subjective effects? 2. How strongly do you actually believe that you will experience subjective effects? 3. How strongly do you expect the effects of 5-MeO-DMT to be pleasant or positive? 4. How strongly do you expect the effects of 5-MeO-DMT to be unpleasant or distressing? The items are rated on a scale from 1 ("not at all") to 9 ("very").	Up to 14 days (from Screening (Session 1) to Drug administration session (Session 2) until end-of-study-visit (EOS, Session 3))
Urinary excretion of 5-MeO-DMT	Urine samples will be collected throughout the whole time interval up to 3 hours after substance administration to assess the urinary excretion profile of 5-MeO-DMT and its metabolites.	Up to 3 hours at substance administration session (Session 2)

Collaborators and Investigators

• Sponsor: University Hospital, Basel, Switzerland
• Investigators: Principal Investigator: Severin Vogt, Dr. med., University Hospital Basel, Division of Clinical Pharmacology and Toxicology

Study record dates

Study Major Dates

• Study Start (Estimated): March 31, 2026
• Primary Completion (Estimated): March 1, 2028
• Study Completion (Estimated): March 1, 2028

Study Registration Dates

• First Submitted: February 6, 2026
• First Submitted That Met QC Criteria: February 24, 2026
• First Posted (Actual): March 3, 2026

Study Record Updates

• Last Update Posted (Actual): March 3, 2026
• Last Update Submitted That Met QC Criteria: February 24, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Infusion; psychedelic
• Additional Relevant MeSH Terms: Organic Chemicals; Heterocyclic Compounds; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring; Amines; Indoles; Biogenic Monoamines; Biogenic Amines; Tryptamines; N,N-Dimethyltryptamine; Bufotenin; Serotonin; Methoxydimethyltryptamines
• Other Study ID Numbers: 2025-02387;am25Vogt2

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No