Tier 2 — strong

Quercetin supplementation and upper respiratory tract infection: A randomized community clinical trial

Serena A Heinz, Dru A Henson, Melanie D Austin, Fuxia Jin, David C Nieman
Pharmacological research 2010 62(3):237

Bibliography

PubMed
PMID 20478383
PubMed Central
PMC7128946
DOI
10.1016/j.phrs.2010.05.001
Funding
Funding was not specified in the indexed record or the disclosure metadata available for this entry.
Competing interests
Reported disclosure: S. A. Heinz, D. A. Henson, M. D. Austin, and F. Jin declare no conflicts of interest. D. C. Nieman holds a position on the science advisory board for Quercegen Pharma.

Study snapshot

DesignRandomized double-blind placebo-controlled community trial
ModelHuman intervention research
Sample1,002 adults aged 18–85 years
InterventionQuercetin 500 or 1,000 mg/day in supplements or placebo
Duration12 weeks
EndpointsSymptoms and quality of life

What the study showed, in plain terms

Published in 2010, this source examined immunity and respiratory health. Design: Randomized double-blind placebo-controlled community trial. Sample/model: 1,002 adults aged 18–85 years. The exposure or intervention was Quercetin 500 or 1,000 mg/day in supplements or placebo. Follow-up or treatment period: 12 weeks.

There was no overall reduction in upper-respiratory illness outcomes. A fitter subgroup aged at least 40 showed lower symptom severity and sick days at 1,000 mg.

Positive subgroup findings do not replace the null overall result. Other publications report additional outcomes from the same community trial.

Continue with Quercetin Data Center

For topic-level interpretation, read Quercetin for Immune Health, Colds and COVID-19. This is a related guide; the citation panel separately identifies articles that directly cite this paper.

Key findings

  • There was no overall reduction in upper-respiratory illness outcomes.
  • A fitter subgroup aged at least 40 showed lower symptom severity and sick days at 1,000 mg.
  • The recorded outcome domains were Symptoms and quality of life.
  • The result applies to the tested exposure: Quercetin 500 or 1,000 mg/day in supplements or placebo; 12 weeks.

What this study can and cannot tell us

  • Positive subgroup findings do not replace the null overall result. Other publications report additional outcomes from the same community trial.
  • An individual controlled trial must be interpreted alongside its comparator, sample size, endpoint selection and independent replication. It does not validate a different commercial formulation or a general longevity claim.
  • Companion or correction records are linked below. They should not be counted automatically as independent replications; see the individual source notes for the relationship.
  • Source basis: Source check: accessible full text and indexed metadata. Missing method details, funding information or participant denominators are not inferred.

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Citation network

Articles citing this research paper

3 articles

Biohack Blueprint analyses that reference this study in their evidence base.

Editorial review

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Dr. Khaled Mahmoud, MBBChCritical Care Medicine, Longevity Science & Editorial Direction Dr. Amr Yasser, PhDCardiometabolic, Musculoskeletal, Gut & Bioavailability Dr. Abdulla Mostafa, PhDCellular Senescence, Neurological, Mitochondrial & Brain-Ageing Biology