Kratom PharmacodynamicsNCT06640569
Preliminary Characterization of Commercial Kratom Extract Products
An observational study of Kratom Pharmacodynamics and Kratom Pharmacokinetics, run by Johns Hopkins University at 2 sites in United States.
Trial summary
To understand the acute subjective, physiological, and cognitive effects of commercial kratom extract products among US adults who consume these products regularly, and to understand how these products are metabolized by the human body. Read more about this study
- Who is it for?
- Ages 21 years and olderHealthy volunteers can take part
- Conditions the study is for
- Kratom Pharmacodynamics, Kratom Pharmacokinetics
- Type of treatment
- Pill or oral medicine
- How many people
- 2 participants
- Where
- 2 sitesUnited States
- Study dates
- 11 Nov 2024to 23 Jul 2026
- Phase
- Observational
- 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 21 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Study population: US adults who use kratom extract products on a regular basis
Who may be able to join
- 1) >21 years old;
- 2) Experienced kratom extract product consumer of one of the leading US brands listed in the study protocol;
- 3) Reports a specific kratom extract product brand and specific dose amount (or range of typical dose amount) on the online screener;
- 4) English language proficient;
- 5) Willingness to provide requested samples of the kratom extract product currently being taken.
Who cannot join
- 1) Reports any acute adverse or unexpected or otherwise sudden health event related to their typical kratom product dose that occurred within 30 days of screening;
- 2) Having ever sought medical attention for an acute adverse health event as a result of taking any kratom product;
- 3) Cannot or will not provide their kratom extract product samples in the form of an unopened package that is clearly labeled with at least the product and vendor name;
- 4)The kratom extract product used by the participant has any semi-synthetic or fully synthetic ingredient listed or is known by the study team to have such an ingredient;
- 5) Currently breastfeeding or pregnant;
- 6) history or current diagnosis of psychotic disorder;
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- 7) current untreated bipolar disorder; 8) current untreated major depressive disorder;
- 8) Current physical dependence on alcohol, benzodiazepines, or opioids (self-reported or otherwise evidenced) requiring medical intervention;
- 9) Reports use of fentanyl within the past month and/or has a fentanyl positive drug screen;
- 10) Discordance between self-reported substance use and drug screen results obtained during screening;
- 11)Any physical, psychiatric, environmental, situational, or kratom product-related condition considered by the study team to increase risk or undue burden.
Trial locations and contacts
2 sites in 1 country.
United States2 sites
Johns Hopkins University Behavioral Pharmacology Research Unit
Baltimore, Maryland, 21224
Johns Hopkins University
Baltimore, Maryland, 21224
About this study
To understand the acute subjective, physiological, and cognitive effects of commercial kratom extract products among US adults who consume these products regularly, and to understand how these products are metabolized by the human body.
Read the detailed description
Kratom products, made from the botanical Mitragyna speciosa, have proliferated in the United States since 2006 and now include a variety of brands and formulations. Kratom whole-leaf products and kratom leaf-derived extract products are the two major types of products within the marketplace. To date, most studies have examined kratom whole-leaf products, both in terms of self-report from consumers and in terms of two US-based, small lab-based pharmacokinetic/pharmacodynamic (PK/PD) studies. In order to follow-up on the investigators' prior work examining the acute effects of kratom in adults (age 21 or older) who regularly use whole-leaf kratom products, the investigators propose a pilot study (N=16) that purposefully samples US adults who use popular kratom extract products sold legally in most of US, including the state of Maryland. Despite the widespread use of kratom extract products, particularly among the best-selling brands, the investigators have no independently collected and published data derived from human laboratory studies on the PK/PD associated with these products. The investigators will conduct a within-person, single-dose pilot study wherein 16 adult consumers of kratom extract products will self-administer a single oral dose of the participant's kratom extract. As this is an exploratory pilot study, the investigators are not making a priori hypothesis. Rather, this is a proof-of-concept pilot study needed to first measure the basic PK and PD (physiological, subjective, cognitive) responses to extract product servings taken by adults who consumed the extracts regularly. There is immediate public health need to better understand kratom extract consumer experiences given that these products are unregulated but widely used. Such data have ecological validity and can inform next steps for funding and research.
- Conditions
- Kratom Pharmacodynamics, Kratom Pharmacokinetics
- Keywords
- kratom, kratom extracts, pharmacokinetics, behavioral pharmacology, Mitragyna speciosa
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| US Adult Kratom Extract Consumers | Participants who regularly consume commercial kratom extracts will orally self-administer a single serving of their commercial kratom extract product under direct observation in order to evaluate acute physiological, subjective, and cognitive effects and determine pharmacokinetics. Participants will undergo direct observation and assessment for acute self-administration and for a period following the peak effects (i.e., a period of short abstinence). Physiological, subjective, and cognitive effects will be measured in an inpatient unit where the participant will reside for 2 days and 1 night (consecutive). |
What is being measured
The primary outcome is the main question the study is designed to answer.
Drug Effects Questionnaire
Drug Effects Questionnaire (DEQ) visual analogue scale (0-100) rating for DEQ item "feeling" effects and "liking" effects. 0 is the measure of least impactful 'effect'.
Measured: Administered at 7 timepoints on Study Days 1-2
Cognitive Effects as assessed by the Digit Symbol Substitution Task
The 2-minute computerized Digit Symbol Substitution Task (DSST) outcome of total number of correct responses (accuracy) within the 2-minute test window. This will evaluate cognitive performance and impairment.
Measured: Administered at 7 time points on Study Days 1-2
Pupil size
Pupil diameter in mm under stable light conditions using a pupilometer.
Measured: Measured at 7 timepoints on Study Days 1-2
Resting Heart Rate
Resting heart rate in beats per minute.
Measured: Measured at 7 timepoints on Study Days 1-2
Secondary outcomes (1)
Qualitative Interview
Qualitative interview of participants' experience with kratom products and how use has changed over time. Will take approximately 1.5 - 2 hours to complete.
Measured: Study Day 2
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Oct 2024
- Study start11 Nov 2024
- Primary completion23 Jul 2026
- Study completion23 Jul 2026
Why it stopped: Original PI left study team, ending project funding.
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Kratom PharmacodynamicsStudies of the same condition, open and under way.
- More trials run by Johns Hopkins UniversityThe 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
- Observational
- Observational model
- Other
- Time perspective
- Prospective
- Enrolment
- 2 participants (actual)
Sponsor and investigators
- Lead sponsor
- Johns Hopkins University
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Kirsten E Smith, MSW, PhD, Principal investigator, Johns Hopkins University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06640569
- Sponsor's protocol ID
- IRB00440647
- Status last verified
- Aug 2026
- First submitted
- 9 Oct 2024
- Last updated
- 13 Aug 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Data sharing agreements/materials will be implemented to share biospecimen data and limited datasets with deidentified participant information to collaborators for bioanalytics. No protected health information or personally identifiable information will be shared and all data will be coded with unique participant Identification.
Study at a glance
From the registry record, last updated by the sponsor on 13 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Preliminary Characterization of Commercial Kratom Extract Products
- ClinicalTrials.gov ID
- NCT06640569
- Acronym / sponsor ID
- IRB00440647
- Conditions
- Kratom Pharmacodynamics, Kratom Pharmacokinetics
- Keywords
- kratom, kratom extracts, pharmacokinetics, behavioral pharmacology, Mitragyna speciosa
- Study type
- Observational
- Recruitment status
- TerminatedReason stopped: Original PI left study team, ending project funding.
- Enrolment
- 2 participants (actual)
- Lead sponsor
- Johns Hopkins UniversityUniversity, hospital or other
- Study start
- 11 Nov 2024 (actual)
- Primary completion
- 23 Jul 2026 (actual)
- Study completion
- 23 Jul 2026 (actual)
- First posted
- 15 Oct 2024 (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.
To understand the acute subjective, physiological, and cognitive effects of commercial kratom extract products among US adults who consume these products regularly, and to understand how these products are metabolized by the human body.
Detailed description
Kratom products, made from the botanical Mitragyna speciosa, have proliferated in the United States since 2006 and now include a variety of brands and formulations. Kratom whole-leaf products and kratom leaf-derived extract products are the two major types of products within the marketplace. To date, most studies have examined kratom whole-leaf products, both in terms of self-report from consumers and in terms of two US-based, small lab-based pharmacokinetic/pharmacodynamic (PK/PD) studies. In order to follow-up on the investigators' prior work examining the acute effects of kratom in adults (age 21 or older) who regularly use whole-leaf kratom products, the investigators propose a pilot study (N=16) that purposefully samples US adults who use popular kratom extract products sold legally in most of US, including the state of Maryland. Despite the widespread use of kratom extract products, particularly among the best-selling brands, the investigators have no independently collected and published data derived from human laboratory studies on the PK/PD associated with these products. The investigators will conduct a within-person, single-dose pilot study wherein 16 adult consumers of kratom extract products will self-administer a single oral dose of the participant's kratom extract. As this is an exploratory pilot study, the investigators are not making a priori hypothesis. Rather, this is a proof-of-concept pilot study needed to first measure the basic PK and PD (physiological, subjective, cognitive) responses to extract product servings taken by adults who consumed the extracts regularly. There is immediate public health need to better understand kratom extract consumer experiences given that these products are unregulated but widely used. Such data have ecological validity and can inform next steps for funding and research.
Study design
- Observational model
- Other
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| US Adult Kratom Extract Consumers | – | –Participants who regularly consume commercial kratom extracts will orally self-administer a single serving of their commercial kratom extract product under direct observation in order to evaluate acute physiological, subjective, and cognitive effects and determine pharmacokinetics. Participants will undergo direct observation and assessment for acute self-administration and for a period following the peak effects (i.e., a period of short abstinence). Physiological, subjective, and cognitive effects will be measured in an inpatient unit where the participant will reside for 2 days and 1 night (consecutive). |
Who may qualify
- Ages
- 21 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- US adults who use kratom extract products on a regular basis
Key inclusion criteria (5 listed)
- 1) >21 years old;
- 2) Experienced kratom extract product consumer of one of the leading US brands listed in the study protocol;
- 3) Reports a specific kratom extract product brand and specific dose amount (or range of typical dose amount) on the online screener;
- 4) English language proficient;
- 5) Willingness to provide requested samples of the kratom extract product currently being taken.
Key exclusion criteria (11 listed)
- 1) Reports any acute adverse or unexpected or otherwise sudden health event related to their typical kratom product dose that occurred within 30 days of screening;
- 2) Having ever sought medical attention for an acute adverse health event as a result of taking any kratom product;
- 3) Cannot or will not provide their kratom extract product samples in the form of an unopened package that is clearly labeled with at least the product and vendor name;
- 4)The kratom extract product used by the participant has any semi-synthetic or fully synthetic ingredient listed or is known by the study team to have such an ingredient;
- 5) Currently breastfeeding or pregnant;
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Drug Effects Questionnaire
Time frame: Administered at 7 timepoints on Study Days 1-2
Drug Effects Questionnaire (DEQ) visual analogue scale (0-100) rating for DEQ item "feeling" effects and "liking" effects. 0 is the measure of least impactful 'effect'.
Cognitive Effects as assessed by the Digit Symbol Substitution Task
Time frame: Administered at 7 time points on Study Days 1-2
The 2-minute computerized Digit Symbol Substitution Task (DSST) outcome of total number of correct responses (accuracy) within the 2-minute test window. This will evaluate cognitive performance and impairment.
Pupil size
Time frame: Measured at 7 timepoints on Study Days 1-2
Pupil diameter in mm under stable light conditions using a pupilometer.
Resting Heart Rate
Time frame: Measured at 7 timepoints on Study Days 1-2
Resting heart rate in beats per minute.
1 secondary outcome
Qualitative Interview
Time frame: Study Day 2
Results and safety
The study was stopped early (reason given: Original PI left study team, ending project funding.). Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 13 Aug 2026.
- Individual participant dataSharing planned: Yes. Data sharing agreements/materials will be implemented to share biospecimen data and limited datasets with deidentified participant information to collaborators for bioanalytics. No protected health information or personally identifiable information will be shared and all data will be coded with unique participant Identification.
Related trials for Kratom Pharmacodynamics
RecruitingObservational study
Direct Observation Study of Kratom Product Effects Among Regular Consumers
Kratom Pharmacokinetics, Kratom Pharmacodynamics
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.
Kirsten E Smith, MSW, PhD principal investigator
Johns Hopkins University
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Kratom Pharmacodynamics and Kratom Pharmacokinetics, run by Johns Hopkins University at 2 sites in United States.
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 5 inclusion and 11 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: stopped early, as of the sponsor's last update on 13 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in United States. 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. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study was stopped early (reason given: Original PI left study team, ending project funding.). Results are not available in the source record.
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?
Drug Effects Questionnaire (time frame: Administered at 7 timepoints on Study Days 1-2). The study lists 4 primary outcomes in all. 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 13 Aug 2026; AzTrials last refreshed its copy on 7 Nov 2026.