Tier 2 — strong

Pure dietary flavonoids quercetin and (-)-epicatechin augment nitric oxide products and reduce endothelin-1 acutely in healthy men

Wai Mun Loke, Jonathan M Hodgson, Julie M Proudfoot, Allan J McKinley, Ian B Puddey, Kevin D Croft
The American journal of clinical nutrition 2008 88(4):1018

Bibliography

PubMed
PMID 18842789
DOI
10.1093/ajcn/88.4.1018
Funding
Funding was not specified in the indexed record or the disclosure metadata available for this entry.
Competing interests
A competing-interest declaration was not available in the indexed record or the disclosure metadata used for this entry.

Study snapshot

DesignRandomized placebo-controlled crossover vascular biomarker study
ModelHuman intervention research
Sample12 healthy men
InterventionQuercetin 200 mg, epicatechin, EGCG, or water control
DurationAcute single-dose comparisons
EndpointsOxidative-stress measures

What the study showed, in plain terms

Published in 2008, this source examined cardiovascular and metabolic health. Design: Randomized placebo-controlled crossover vascular biomarker study. Sample/model: 12 healthy men. The exposure or intervention was Quercetin 200 mg, epicatechin, EGCG, or water control. Follow-up or treatment period: Acute single-dose comparisons.

Quercetin increased selected nitric-oxide-related measures and reduced endothelin-1; oxidative-stress markers did not improve.

Small acute biomarker experiment. It does not establish sustained endothelial benefit or cardiovascular event prevention.

Continue with Quercetin Data Center

For topic-level interpretation, read Quercetin for Weight Loss, Blood Sugar and Fatty Liver: Human Evidence. This is a related guide; the citation panel separately identifies articles that directly cite this paper.

Key findings

  • Quercetin increased selected nitric-oxide-related measures and reduced endothelin-1; oxidative-stress markers did not improve.
  • The recorded outcome domains were Oxidative-stress measures.
  • The result applies to the tested exposure: Quercetin 200 mg, epicatechin, EGCG, or water control; Acute single-dose comparisons.

What this study can and cannot tell us

  • Small acute biomarker experiment. It does not establish sustained endothelial benefit or cardiovascular event prevention.
  • 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

Reviewed by the Biohack Blueprint research team

Last verified

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