Radicle GI Health™ RFY: A Study Assessing the Impact of DAO Supplementation on Gastrointestinal and Other Histamine Intolerance Symptoms

September 17, 2026 updated by: Radicle Science

Radicle GI Health™ RFY: A Randomized, Double-Blind, Placebo-Controlled Study Assessing the Impact of DAO Supplementation on Gastrointestinal and Other Histamine Intolerance Symptoms

Radicle GI Health™ RFY: A Randomized, Double-Blind, Placebo-Controlled Study Assessing the Impact of DAO Supplementation on Gastrointestinal and other Histamine Intolerance Symptoms.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet 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

This is a randomized, double-blind, placebo-controlled study conducted with adult participants, residing in the United States.

Eligible participants will (1) have histamine intolerance symptoms affecting GI health and at least one other organ/system, (2) have the opportunity for meaningful improvement (at least 30%) in their primary health outcome, and (3) express acceptance in taking a product and not knowing its formulation until the end of the study.

Participants that report a known contraindication or with well established, significant safety concerns due to illness will be excluded. Heavy drinkers and those who report they are pregnant, trying to become pregnant, or breastfeeding will be excluded. Participants that report taking medications with a known contraindication or with well-established, significant safety concerns will be excluded.

Self-reported data are collected electronically from eligible participants for 7 weeks. Participant reports of health indicators will be collected at enrollment and throughout the active period of study product usage. All study assessments will be electronic; there are no in-person visits or assessments for this real-world evidence study.

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.
550

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.
  • Not Applicable

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 Contact Backup

Study Locations

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 105 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion

Participants must meet all the following criteria:

  • Adults, at least 21 years of age at the time of electronic consent, inclusive of all ethnicities, races, and gender identities

    • Assigned sex at birth will determine sex-specific recruitment and PROs (male vs female) employed, when needed

  • Resides in the United States

  • Report histamine intolerance symptoms affecting GI health and at least one other organ/system, determined from the Histamine Intolerance Checklist

  • Has the opportunity for at least 30% improvement in their primary health outcome

  • Expresses a willingness to take a study product and not know the product identity (active or placebo) until the end of the study

Exclusion

Individuals who report any of the following during screening may be excluded from participation.

  • Report being pregnant, trying to become pregnant, or breastfeeding

  • Unable to provide a valid US shipping address and mobile phone number

  • Reports current enrollment in another clinical trial

  • Reports being a heavy drinker (defined as drinking 3 or more alcoholic beverages per day)

  • Unable to read and understand English at a 7th grade level

  • Reports a current and/or recent (up to 3 months ago) major illness and/or surgery that poses a known, significant safety risk.

  • Reports a diagnosis of cardiac dysfunction, liver or kidney disease that presents a known contraindication and/or a significant safety risk with any of the study product ingredients. This may include:

    • NYHA Class III or IV congestive heart failure, atrial fibrillation, uncontrolled arrhythmias, cirrhosis, end-stage liver disease, stage 3b or 4 chronic kidney disease, or kidney failure

  • Reports taking medications that have a well-established moderate or severe interaction, posing a substantial safety risk with any of the study product ingredients. This may include:

    • Anticoagulants, antihypertensives, anxiolytics, antidepressants, chemotherapy, immunotherapy, sedative hypnotics, seizure medications, medications that warn against grapefruit consumption, corticosteroids at doses greater than 5 mg per day, diabetic medications, oral anti-infectives (antibiotics, antifungals, antivirals) to treat an acute infection, antipsychotics, MAOIs, or thyroid products

  • Reports current use of the primary ingredient(s) and/or similar product(s) to the active study product(s) that may limit the effects of the study products and/or pose a safety risk

  • Lack of reliable daily access to the internet

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: Parallel Assignment
  • Masking: Double

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.
Experimental: Active GI Health Product 1

Active GI Health Product 1
Dietary supplement: Active GI Health Product 1

Participants will use their Active GI Health Product 1 as directed for a period of 6 weeks
Placebo Comparator: Placebo GI Health Control

Placebo GI Health Control
Dietary supplement: Placebo GI Health Control

Participants will use their Placebo GI Health Control as directed for a period of 6 weeks

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
Change in the severity of gastrointestinal symptoms
Time Frame: 7 weeks

Change in the severity of gastrointestinal symptoms: Difference between rates of change over time in gastrointestinal symptoms score as assessed by GSRS (scale 15-105; with higher scores equaling greater severity)
7 weeks

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Change in GI-related Quality of Life (QOL)
Time Frame: 7 weeks

Change in GI-related Quality of Life (QOL): Difference between rates of change over time in GI-related QOL as assessed by Digestion-associated Quality of Life Questionnaire (scale 0-9; where the higher scores correspond to worse GI-related quality of life)
7 weeks
Change in rhinitis symptom control
Time Frame: 7 weeks

Change in rhinitis symptom control: Change in control of rhinitis symptoms as assessed by the Rhinitis Control Assessment Test (RCAT) (Scores range from 6 to 30, with higher scores indicating better rhinitis symptom control.)
7 weeks
Change in itch severity
Time Frame: 7 weeks

Change in the severity of itching: Difference between rates of change over time in itch severity as assessed by the Itch Severity Scale (ISS; scale 0-21; with higher scores equaling greater severity)
7 weeks

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Minimal clinically important difference (MCID) in the severity of gastrointestinal symptoms
Time Frame: 7 weeks

Minimal clinically important difference (MCID) in the severity of gastrointestinal symptoms: Likelihood of experiencing minimal clinically important difference in gastrointestinal symptoms score as assessed by GSRS (scale 15-105; with higher scores equaling greater severity)
7 weeks
Minimal clinically important difference (MCID) in GI-related Quality of Life (QOL)
Time Frame: 7 weeks

Minimal clinically important difference (MCID) in GI-related Quality of Life (QOL): Likelihood of experiencing minimal clinically important difference in GI-related QOL as assessed by Digestion-associated Quality of Life Questionnaire (scale 0-9; where the higher scores correspond to worse GI-related quality of life)
7 weeks
Minimal clinically important difference in rhinitis symptom control
Time Frame: 7 weeks

Minimal clinically important difference in rhinitis symptom control: Likelihood of experiencing minimal clinically important difference in control of rhinitis symptoms as assessed by the Rhinitis Control Assessment Test (RCAT) (Scores range from 6 to 30, with higher scores indicating better rhinitis symptom control.)
7 weeks
Minimal clinically important difference (MCID) in the severity of itching
Time Frame: 7 weeks

Minimal clinically important difference (MCID) in the severity of itching: Likelihood of experiencing minimal clinically important difference in itch severity as assessed by ISS (scale 0-21; with higher scores equaling greater severity)
7 weeks

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.
Radicle Science

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: Susan Hewlings, Radicle Science

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.

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 (Estimated)

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.
October 8, 2026

Primary Completion (Estimated)

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.
October 8, 2027

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.
October 8, 2027

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).
September 17, 2026

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.
September 17, 2026

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.
September 23, 2026

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.
September 23, 2026

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.
September 17, 2026

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, 2026

More Information

Terms related to this study

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.
  • RADX_P_2610_RFY

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Data will not be shared with researchers outside of Radicle Collaborators on this study.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

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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