Quercetin in the Prevention of Covid-19 Infection

Randomized, Placebo-controlled Clinical Trial to Evaluate the Efficacy of an Oral Nutritional Supplement Based on Quercetin in the Prevention of Covid-19 Infection for a Duration of 3 Months

Status

Completed

Phases

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT05037240

Enrollment

Registered

2021-09-08

Start date

2021-01-12

Completion date

2021-05-25

Last updated

2021-09-08

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Covid19

Brief summary

Quercetin is a flavonol, a subclass of flavonoid compounds. Of the flavonol molecules, quercetin is the most abundant in fruit and vegetables. Quercetin flavonol is characterized by 3 crucial properties: antioxidant, anti-inflammatory and immunomodulatory. The combination of these 3 properties makes quercetin an excellent candidate for dealing with situations in which oxidative stress, inflammation and the immune system are involved. The purpose of the study is to evaluate the effectiveness of an oral nutritional supplement based on quercetin in the prevention of Covid-19 infection.

Interventions

DIETARY_SUPPLEMENTQuercetin

Quercetin (500 mg), 2 times a day for 3 months

COMBINATION_PRODUCTPlacebo

500 mg, 2 times a day for 3 months

Study design

Allocation

RANDOMIZED

Intervention model

PARALLEL

Primary purpose

PREVENTION

Masking

DOUBLE (Subject, Outcomes Assessor)

Eligibility

Sex/Gender

ALL

Age

18 Years to No maximum

Healthy volunteers

Yes

Inclusion criteria

* Absence of Covid-19 infection

Exclusion criteria

* Previous Sars-Cov-2 infection demonstrated with antibody positivity through venous sampling * Demonstrated presence of Sars-Cov-2 through a nasopharyngeal antigenic swab before the start of oral nutritional supplementation

Design outcomes

Primary

Measure	Time frame	Description
Prevention of Covid-19 infection	Absence of Covid-19 infection at 3 months	A nasopharyngeal antigenic swab

Countries

Italy

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026