Comparing the Effects of Psilocin and Psilocybin in Healthy Adults

June 5, 2025 updated by: Joshua Woolley, MD, PhD, University of California, San Francisco

Comparison of the Effects of PEX20 (Oral Psilocin), PEX30 (Sublingual Psilocin), and PEX10 (Oral Psilocybin) in Healthy Adults

To compare the physiological and psychological effects of psilocin taken orally by pill or sublingually by dissolving a tablet under the tongue to those of psilocybin taken by pill in healthy adults.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Active, not recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

The primary goal of this study is to compare the physiological and psychological effects of psilocin taken orally by pill or sublingually dissolved under the tongue to those of psilocybin taken by pill. Twenty participants, ages 25 to 50, with one previous experience with psychedelics, and who meet all other inclusion and exclusion criteria at screening will be enrolled. After baseline assessments, participants will engage in preparatory visits with trained facilitators, followed by drug administration, supervised by the facilitators and a clinician who will conduct safety monitoring throughout. Participants will then complete assessment and integration sessions with the facilitators in order to help process the experience. The same preparation, procedures, integration, and supervision will be repeated up to three more times with each participant.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
20

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • United States
    • California
      • San Francisco, California, United States, 94143
        • University of California, San Francisco

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

21 years to 46 years (Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Age 25 to 50
  • Comfortable speaking and writing in English
  • Commit to attending all study visits and remote data collection tasks
  • No planned surgeries during the study
  • Had at least one prior experience with a psychedelic substance
  • Generally mentally and physically healthy
  • Agree to abstain from THC, CBD, or nicotine products during study

Exclusion Criteria:

  • Participated in another clinical trial within 30 days of entry to this trial
  • Regular use of medications that may have problematic interactions with psilocybin, including but not limited to dopamine agonists, MAO inhibitors, N-methyl-D-aspartate (NMDAR) antagonists, antipsychotics, and stimulants
  • A health condition that makes study unsafe or unfeasible, determined by study physicians

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: Oral & Sublingual Psilocin, & Oral Psilocybin
Every participant will be administered Oral Psilocin, Sublingual Psilocin, and oral psilocybin in a randomized order.
Drug: Psilocin
17.5mg oral psilocin with psychological support and physiological monitoring
Drug: Psilocybin
25mg oral psilocybin with psychological support and physiological monitoring
Drug: Sublingual Psilocin
2.18mg - 4.36mg sublingual psilocin with psychological support and physiological monitoring
Active Comparator: Sublingual Psilocin
Depending on a number of factors, participants may complete a fourth session where they receive sublingual psilocin for the second time.
Drug: Sublingual Psilocin
2.18mg - 4.36mg sublingual psilocin with psychological support and physiological monitoring

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Physiological Effects
Time Frame: Baseline to 8 hours following drug delivery
blood pressure
Baseline to 8 hours following drug delivery
Physiological Effects
Time Frame: Baseline to 8 hours following drug delivery
heart rate
Baseline to 8 hours following drug delivery
Psychological Effects
Time Frame: Baseline to 4 weeks after drug delivery
- Peak psychedelic intensity ratings will be measured using Likert scale (0-10 rating scale, 0=not intense at all, 10=highest intensity imaginable)
Baseline to 4 weeks after drug delivery
Psychological Effects
Time Frame: Baseline to 4 weeks after drug delivery
- Peak psychological effects will be measured by the Altered States of Consciousness (5D-ASC) questionnaire at the end of each dosing session
Baseline to 4 weeks after drug delivery
Psychological Effects
Time Frame: Baseline to 4 weeks after drug delivery
- Peak psychological effects will be measured by the Challenging Experiences Questionnaire at the end of each dosing session
Baseline to 4 weeks after drug delivery
Psychological Effects
Time Frame: Baseline to 4 weeks after drug delivery
- Persistent changes in attitude, mood, and behavior will be assessed using Persisting Effects Questionnaire, administered 4 weeks after each dosing session
Baseline to 4 weeks after drug delivery
Psychological Effects
Time Frame: Baseline to 4 weeks after drug delivery
- Personality profiles will be measured using the Big Five Inventory at baseline and 4 weeks after each dosing session
Baseline to 4 weeks after drug delivery
Adverse Effects
Time Frame: Baseline to 24 hours after dosing session
  • Acute hypertension, hypotension, tachycardia, or bradycardia will be detected through blood pressure and heart rate monitoring at 10 minutes prior to drug administration and measured frequently up to 360 minutes following administration
  • Other dosing-related side effects including descriptive reports of nausea, headaches, dizziness, weakness, drowsiness, paresthesia, or blurred vision will be assessed during check-ins, after dosing effects have waned, and 24 hours following dosing
Baseline to 24 hours after dosing session

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of California, San Francisco

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Filament Health Corp.

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Joshua Woolley, MD/PhD, University of California, San Francisco

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
May 26, 2022

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
January 16, 2025

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
July 1, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
March 7, 2022

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 30, 2022

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
April 8, 2022

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 10, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 5, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
September 1, 2024

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • IRB#21-33765
  • PR#202143H (Other Identifier: Research Advisory Panel - California)
  • 156917 (Other Identifier: FDA)

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

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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