Tier 2 — strong

Carbon dioxide is the major metabolite of quercetin in humans

T Walle, U K Walle, P V Halushka
The Journal of nutrition 2001 131(10):2648

Bibliography

PubMed
PMID 11584085
DOI
10.1093/jn/131.10.2648
Funding
Indexed grant support: GM55561 — NIGMS NIH HHS — United States; RR01070 — NCRR NIH HHS — United States. The indexed list may not contain the complete funding declaration.
Competing interests
A competing-interest declaration was not available in the indexed record or the disclosure metadata used for this entry.

Study snapshot

DesignHuman radiolabeled disposition and mass-balance study
ModelHuman intervention research
SampleHealthy volunteers; breath-recovery substudy in 3 people
InterventionRadiolabeled quercetin 100 mg orally or 0.3 mg intravenously
Duration72-hour plasma, urine, stool, and breath collections
EndpointsExposure and pharmacokinetics

What the study showed, in plain terms

Published in 2001, this source examined forms, absorption and food sources. Design: Human radiolabeled disposition and mass-balance study. Sample/model: Healthy volunteers; breath-recovery substudy in 3 people. The exposure or intervention was Radiolabeled quercetin 100 mg orally or 0.3 mg intravenously. Follow-up or treatment period: 72-hour plasma, urine, stool, and breath collections.

A substantial fraction of radiolabel appeared as exhaled carbon dioxide, showing extensive metabolism beyond urinary quercetin conjugates.

Total radiolabel tracks breakdown products as well as parent compound. Its absorption estimate should not be equated with unchanged quercetin bioavailability.

Continue with Quercetin Data Center

For topic-level interpretation, read Quercetin Forms: Dihydrate, Phytosome, Liposomal and Glycosides. This is a related guide; the citation panel separately identifies articles that directly cite this paper.

Key findings

  • A substantial fraction of radiolabel appeared as exhaled carbon dioxide, showing extensive metabolism beyond urinary quercetin conjugates.
  • The recorded outcome domains were Exposure and pharmacokinetics.
  • The result applies to the tested exposure: Radiolabeled quercetin 100 mg orally or 0.3 mg intravenously; 72-hour plasma, urine, stool, and breath collections.

What this study can and cannot tell us

  • Total radiolabel tracks breakdown products as well as parent compound. Its absorption estimate should not be equated with unchanged quercetin bioavailability.
  • 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.
  • Source basis: Source check: PubMed abstract and indexed metadata; full methods were not independently confirmed for this entry. Missing method details, funding information or participant denominators are not inferred.

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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