A Phase 2 interventional study of zinc-green tea extract-ascorbic acid and Placebo in Respiratory Viral Infection, sponsored by University of Missouri-Columbia. Terminated at 1 site in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2025-03-07.
Sponsored by University of Missouri-Columbia · Phase 2, Interventional, and Treatment
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.
6,687 studies on the registry are indexed under Infections; 807 are open to participants now.
This study's enrollment of 17 is below the median of 120 across 4,200 interventional studies indexed under Infections.
Browse Infections studies →University of Missouri-Columbia is the lead sponsor of 357 studies on the registry; 70 are open to participants now.
Of its 42 completed or terminated interventional studies of FDA-regulated products, 28 (67%) have results posted.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
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
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 each zinc citrate, green tea extract, and ascorbic acid.
Compounded capsules containing microcrystalline cellulose.
Number of Patients Who Recovered From Cold and Flu-like Symptoms
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)
Time frame: 7 days of follow-up
Number of Patients With Self-reported Adverse Events
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
Time frame: 7 days of follow-up
Number of Patients Who Reported Days of Absence and/or Healthcare Visits
Absence includes missed days from work or school and healthcare visits include hospitalization or physician office visit(s) for respiratory viral illness related complications
Time frame: 7 days of follow-up
| Milestone | Zinc-green Tea Extract-ascorbic Acid | Placebo |
|---|---|---|
| Started | 5 | 9 |
| Completed | 5 | 9 |
| Not completed | 0 | 0 |
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)
| Participants | Zinc-green Tea Extract-ascorbic Acid | Placebo |
|---|---|---|
| Number of Patients Who Recovered From Cold and Flu-like Symptoms | 3 | 4 |
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
| Participants | Zinc-green Tea Extract-ascorbic Acid | Placebo |
|---|---|---|
| Number of Patients With Self-reported Adverse Events | 2 | 3 |
Absence includes missed days from work or school and healthcare visits include hospitalization or physician office visit(s) for respiratory viral illness related complications
| Participants | Zinc-green Tea Extract-ascorbic Acid | Placebo |
|---|---|---|
| Number of Patients Who Reported Days of Absence and/or Healthcare Visits | 5 | 3 |
Collected over 7 days for each study subject. Non-serious events are listed at a 0% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Zinc-green Tea Extract-ascorbic Acid | 0/5 (0%) | 0/5 (0%) | 2/5 (40%) |
| Placebo | 0/9 (0%) | 0/9 (0%) | 3/9 (33.3%) |
| Event | Zinc-green Tea Extract-ascorbic Acid | Placebo |
|---|---|---|
| Gastrointestinal upsetGastrointestinal disorders | 2/5 | 2/9 |
| Allergic ReactionSkin and subcutaneous tissue disorders | 0/5 | 1/9 |
| Age, Continuous(years) | Zinc-green Tea Extract-ascorbic Acid | Placebo | Total |
|---|---|---|---|
| Mean | 19.4 (18 to 22) | 23.6 (18 to 33) | 21.5 (18 to 33) |
| Sex: Female, Male(Participants) | Zinc-green Tea Extract-ascorbic Acid | Placebo | Total |
|---|---|---|---|
| Female | 1 | 3 | 4 |
| Male | 4 | 6 | 10 |
| Race (NIH/OMB)(Participants) | Zinc-green Tea Extract-ascorbic Acid | Placebo | Total |
|---|---|---|---|
| American Indian or Alaska Native | 0 | 0 | 0 |
| Asian | 0 | 0 | 0 |
| Native Hawaiian or Other Pacific Islander | 0 | 0 | 0 |
| Black or African American | 1 | 3 | 4 |
| White | 2 | 6 | 8 |
| More than one race | 2 | 0 | 2 |
| Unknown or Not Reported | 0 | 0 | 0 |
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University of Missouri-Columbia