Zinc and Green Tea Extract for Community Respiratory Viral Infections

February 17, 2025 updated by: Syed Naqvi, University of Missouri-Columbia

Evaluation of Combination Zinc and Green Tea Extract Supplementation on Reduction in Symptom Duration and Severity Associated With Community Respiratory Viral Infections: a Randomized Control Trial (ZiPhenol Study)

Zinc and green tea supplementation have both been independently studied for supporting immune health during cold and flu-like illness in non-hospitalized patients with clinical trials demonstrating promising but inconsistent results. Combination therapy may offer an improved effect as the antioxidant compounds found in green tea have been shown to increase cellular zinc concentrations thereby inhibiting viral replication. This study seeks to evaluate the effect of combination supplementation using established doses of zinc and green tea extract on symptom duration and severity from cold and flu-like illness, including COVID-19, in adult community patients enrolled in a randomized placebo-controlled trial.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Terminated

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.

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 (Actual)

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.
17

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 2

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
    • Missouri
      • Columbia, Missouri, United States, 65212
        • University of Missouri

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

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Provision of signed and dated informed consent form
  2. Stated willingness to comply with all study procedures and availability for the duration of the study
  3. Male or female, aged 18 years and older
  4. Ability to take oral medication and be willing to adhere to the prescribed dosing regimen
  5. Self-reported cold or flu symptoms for < 72 hours

Exclusion Criteria:

  1. Pregnant or actively seeking to become pregnant
  2. Positive for influenza with planned treatment with oseltamivir or baloxavir
  3. Current or planned treatment with an FDA regulated drug (including those under EUA) for COVID-19
  4. Chronic liver disease (i.e. baseline liver function tests (LFTs) > 1.5x the upper limit of normal (ULN) or established cirrhosis
  5. Chronic renal failure stage 4 or greater
  6. History of kidney stones
  7. Acute secondary bacterial infection at the time of enrollment
  8. Requiring hospitalization for any reason at the time of enrollment
  9. History of copper or iron deficiency
  10. Current prescription for quinolone antibiotics, tetracycline antibiotics, or penicillamine at the time of enrollment
  11. Allergy/intolerance to any of the active ingredients under investigation including zinc citrate, green tea, and ascorbic acid (vitamin C)
  12. Patients without decision making capacity
  13. Currently enrolled in another clinical trial for a respiratory viral infection

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: Treatment
  • 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: zinc-green tea extract-ascorbic acid
Randomized patients will take three (3) capsules taken orally two (2) hours following a meal twice daily x5 days and be blinded to study assignment.
Drug: zinc-green tea extract-ascorbic acid
Compounded capsules containing each zinc citrate, green tea extract, and ascorbic acid.
Placebo Comparator: Placebo
Randomized patients will take three (3) capsules taken orally two (2) hours following a meal twice daily x5 days and be blinded to study assignment.
Drug: Placebo
Compounded capsules containing microcrystalline cellulose.

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
Number of Patients Who Recovered From Cold and Flu-like Symptoms
Time Frame: 7 days of follow-up
Recovery is defined as achieving a daily total symptom severity score of 0 or 1 within 7 days using an established 12 symptom scoring system, with a severity score ranging from 0-absent to 3-very severe for each symptom assessed (max of 36 points possible; higher scores indicate a greater severity of symptoms)
7 days of follow-up

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
Number of Patients With Self-reported Adverse Events
Time Frame: 7 days of follow-up
Adverse events collected include: nausea, vomiting, indigestion, worsening of shortness of breath or difficulty breathing, allergic reaction including skin rash, and need to seek medical care (e.g. hospitalization or physician visit) for a suspected study drug related adverse effect
7 days of follow-up
Number of Patients Who Reported Days of Absence and/or Healthcare Visits
Time Frame: 7 days of follow-up
Absence includes missed days from work or school and healthcare visits include hospitalization or physician office visit(s) for respiratory viral illness related complications
7 days of follow-up

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 Missouri-Columbia

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.
September 21, 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.
October 31, 2023

Study Completion (Actual)

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.
December 20, 2023

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).
May 18, 2021

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.
May 18, 2021

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.
May 24, 2021

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.
March 25, 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.
February 17, 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.
February 1, 2025

More Information

Terms related to this study

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.
  • 2035652

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

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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