Effect of Quercetin on Prophylaxis and Treatment of COVID-19
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ClinicalTrials.gov Identifier: NCT04377789 |
Recruitment Status :
Completed
First Posted : May 6, 2020
Last Update Posted : February 18, 2021
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Condition or disease | Intervention/treatment | Phase |
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COVID-19 | Dietary Supplement: Quercetin Prophylaxis Dietary Supplement: Quercetin Treatment | Not Applicable |
Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 447 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | None (Open Label) |
Primary Purpose: | Prevention |
Official Title: | The Possible Effect of Quercetin on Prophylaxis and Treatment of COVID-19 |
Actual Study Start Date : | March 20, 2020 |
Actual Primary Completion Date : | July 31, 2020 |
Actual Study Completion Date : | August 31, 2020 |

Arm | Intervention/treatment |
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No Intervention: non-quercetin group
Participants, who accept to enroll the study without having quercetin prophylaxis and who do not have a history of COVID-19, will be in this group.
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Active Comparator: quercetin prophylaxis group
Participants, who takes a daily dose of 500mg quercetin and who not have a history of COVID-19, will be in this group.
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Dietary Supplement: Quercetin Prophylaxis
a daily dose of quercetin (500mg) will be taken by non-COVID-19 intervention group 1 |
Active Comparator: quercetin treatment group
Participants, who takes a daily dose of 1000mg quercetin and who are proven cases for COVID-19, will be in this group.
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Dietary Supplement: Quercetin Treatment
a daily dose of quercetin (1000mg) will be taken by proven COVID-19 cases intervention group 2 |
- Prevalence of COVID-19 calculated using a questionnaire [ Time Frame: 3 months ]Prevalence of COVID-19 in prophylaxis and sham group will be calculated using a questionnaire including hospital records
- Standardized Mortality rate [ Time Frame: 3 months ]Mortality rate will be compared between two groups
- Morbidity rate [ Time Frame: 3 months ]Morbidity rates besides recovery rates from COVID-19 will be documented

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Ages Eligible for Study: | 18 Years and older (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | Yes |
Inclusion Criteria:
- moderate-high risk for COVID-19
- obtained informed consent
Exclusion Criteria:
- declined to participate
- genetic/chromosomal abnormalities
- any kind of sensitivity or allergy for quercetin
- history of previous hypersensitivity with quercetin

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT04377789
Turkey | |
Kanuni Sultan Suleyman Training and Research Hospital | |
Istanbul, Turkey, 34303 |
Responsible Party: | Hasan Onal, Professor, Kanuni Sultan Suleyman Training and Research Hospital |
ClinicalTrials.gov Identifier: | NCT04377789 |
Other Study ID Numbers: |
KSSEAH--0058 |
First Posted: | May 6, 2020 Key Record Dates |
Last Update Posted: | February 18, 2021 |
Last Verified: | February 2021 |
Studies a U.S. FDA-regulated Drug Product: | No |
Studies a U.S. FDA-regulated Device Product: | No |
COVID-19 Respiratory Tract Infections Infections Pneumonia, Viral Pneumonia Virus Diseases Coronavirus Infections Coronaviridae Infections Nidovirales Infections |
RNA Virus Infections Lung Diseases Respiratory Tract Diseases Quercetin Antioxidants Molecular Mechanisms of Pharmacological Action Protective Agents Physiological Effects of Drugs |