Healthy Adult ParticipantsEarly Phase 1NCT07893769
Effects of Different Doses of Ayahuasca on Personality in Healthy Volunteers
A Early Phase 1 study testing Ayahuasca in people with Healthy Adult Participants, run by University of Sao Paulo at 1 site in Brazil.
Trial summary
Randomized, double-blind, placebo-controlled clinical trial that included 28 healthy volunteers allocated to four experimental single dose groups (n = 7 per group) (ayahuasca 0.5 mL/kg, 1.0 mL/kg, 1.5 mL/kg, or placebo) Read more about this study
- Who is it for?
- Ages 18 to 50 yearsHealthy volunteers can take part
- Conditions the study is for
- Healthy Adult Participants
- What is being tested?
- Ayahuasca
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 28 participants
- Where
- 1 siteBrazil
- Study dates
- 1 Jan 2024to 1 Sep 2025
- Phase
- Early Phase 1
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 50 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Healthy adults
Who cannot join
- history of cardiovascular, hepatic, or neurological diseases;
- scores >10 on the Patient Health Questionnaire-9 (PHQ-9) or Generalized Anxiety Disorder-7 (GAD-7), and any psychiatric diagnosis assessed by the Mini International Neuropsychiatric Interview (M.I.N.I.);
- pregnancy/lactation; prior experience with ayahuasca (>2 lifetime uses);
- use of psychoactive medications;
- and significant recreational drug use (e.g., cannabis >20 lifetime uses; other psychedelics >5 uses).
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Effects of Different Doses of Ayahuasca on Personality in Healthy Volunteers: a Double-blind, Randomized, Placebo-controlled Study
Randomized, double-blind, placebo-controlled clinical trial that included 28 healthy volunteers allocated to four experimental single dose groups (n = 7 per group) (ayahuasca 0.5 mL/kg, 1.0 mL/kg, 1.5 mL/kg, or placebo)
- Conditions
- Healthy Adult Participants
- Being tested
- Ayahuasca, Placebo
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
AyahuascaDrug
ayahuasca 0.5 mL/kg
AyahuascaDrug
Ayahuasca 0.5 mL/kg
AyahuascaDrug
Ayahuasca 1.0 mL/kg
AyahuascaDrug
Ayahuasca 1.5 mL/kg
PlaceboOther
Placebo
| Study group | Role | What they receive |
|---|---|---|
| ayahuasca 0.5 mL/kg | Experimental | ayahuasca 0.5 mL/kg Receives: Drug: Ayahuasca |
| ayahuasca 1.0 mL/kg | Experimental | ayahuasca 1.0 mL/kg Receives: Drug: Ayahuasca |
| ayahuasca 1.5 mL/kg | Experimental | ayahuasca 1.5 mL/kg Receives: Drug: Ayahuasca |
| Placebo | Placebo comparator | Placebo Receives: Drug: Ayahuasca; Other: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Personality assessments (primary outcome) were conducted at baseline and at a 21-day follow-up using the NEO Five-Factor Inventory-Revised (NEO-FFI-R)
Units on a Scale (NEO-FFI-R)
Measured: baseline and 21-day follow-up
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 Oct 2026
- Study start1 Jan 2024
- Primary completion1 Sep 2025
- Study completion1 Sep 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Healthy Adult ParticipantsStudies of the same condition, open and under way.
- More trials run by University of Sao PauloThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Early Phase 1
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 28 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Sao Paulo
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Rafael Guimarães dos Santos, University of Sao Paulo
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07893769
- Sponsor's protocol ID
- 75526323.6.0000.5440
- Status last verified
- Oct 2026
- First submitted
- 14 Oct 2026
- Last updated
- 26 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 26 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Different Doses of Ayahuasca on Personality in Healthy Volunteers: a Double-blind, Randomized, Placebo-controlled Study
- ClinicalTrials.gov ID
- NCT07893769
- Acronym / sponsor ID
- 75526323.6.0000.5440
- Conditions
- Healthy Adult Participants
- Phase
- Early Phase 1
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 28 participants (actual)
- Lead sponsor
- University of Sao PauloUniversity, hospital or other
- Study start
- 1 Jan 2024 (actual)
- Primary completion
- 1 Sep 2025 (actual)
- Study completion
- 1 Sep 2025 (actual)
- First posted
- 26 Oct 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Randomized, double-blind, placebo-controlled clinical trial that included 28 healthy volunteers allocated to four experimental single dose groups (n = 7 per group) (ayahuasca 0.5 mL/kg, 1.0 mL/kg, 1.5 mL/kg, or placebo)
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 4
| Arm | Type | Receives |
|---|---|---|
| ayahuasca 0.5 mL/kg | Experimental | Drug: Ayahuascaayahuasca 0.5 mL/kg |
| ayahuasca 1.0 mL/kg | Experimental | Drug: Ayahuascaayahuasca 1.0 mL/kg |
| ayahuasca 1.5 mL/kg | Experimental | Drug: Ayahuascaayahuasca 1.5 mL/kg |
| Placebo | Placebo comparator | Drug: Ayahuasca, Other: PlaceboPlacebo |
Who may qualify
- Ages
- 18 to 50 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (1 listed)
- Healthy adults
Key exclusion criteria (5 listed)
- history of cardiovascular, hepatic, or neurological diseases;
- scores >10 on the Patient Health Questionnaire-9 (PHQ-9) or Generalized Anxiety Disorder-7 (GAD-7), and any psychiatric diagnosis assessed by the Mini International Neuropsychiatric Interview (M.I.N.I.);
- pregnancy/lactation; prior experience with ayahuasca (>2 lifetime uses);
- use of psychoactive medications;
- and significant recreational drug use (e.g., cannabis >20 lifetime uses; other psychedelics >5 uses).
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Ayahuascaayahuasca 0.5 mL/kg | Drug | Placebo, ayahuasca 0.5 mL/kg, ayahuasca 1.0 mL/kg, ayahuasca 1.5 mL/kg |
| AyahuascaAyahuasca 0.5 mL/kg | Drug | ayahuasca 0.5 mL/kg, ayahuasca 1.0 mL/kg, ayahuasca 1.5 mL/kg |
| AyahuascaAyahuasca 1.0 mL/kg | Drug | ayahuasca 0.5 mL/kg, ayahuasca 1.0 mL/kg, ayahuasca 1.5 mL/kg |
| AyahuascaAyahuasca 1.5 mL/kg | Drug | ayahuasca 0.5 mL/kg, ayahuasca 1.0 mL/kg, ayahuasca 1.5 mL/kg |
| PlaceboPlacebo | Other | Placebo |
Primary outcome
Personality assessments (primary outcome) were conducted at baseline and at a 21-day follow-up using the NEO Five-Factor Inventory-Revised (NEO-FFI-R)
Time frame: baseline and 21-day follow-up
Units on a Scale (NEO-FFI-R)
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 26 Oct 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Early Phase 1 study testing Ayahuasca in people with Healthy Adult Participants, run by University of Sao Paulo at 1 site in Brazil.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 26 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Brazil. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Early Phase 1 (sometimes called Phase 0) studies give a very small amount of a treatment to a few people, mainly to see how the body handles it.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Personality assessments (primary outcome) were conducted at baseline and at a 21-day follow-up using the NEO Five-Factor Inventory-Revised (NEO-FFI-R) (time frame: baseline and 21-day follow-up). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 26 Oct 2026.