Quercetin
Overview
Quercetin (C15H10O7) is a dietary flavonol with antioxidant, anti-inflammatory (COX-2/NF-κB inhibition), antiviral, and senolytic properties. A meta-analysis of 7 RCTs found quercetin significantly reduced liver enzymes (ALT, AST, GGT) and improved lipids (LDL↓, TG↓, HDL↑) and CRP in MASLD patients. Oral bioavailability is low; phytosome formulations improve absorption. CYP3A4/CYP2C9 inhibitor at high doses — caution with cyclosporine, statins, warfarin, and benzodiazepines. Generally well tolerated.
Dosage
500 mg · Any time · Can take on empty stomach
Key Interactions
33 verified interactions found
Quercetin partially blocks the absorption and use of vitamin E in the body.
Quercetin kann den oxidativen Verbrauch von Vitamin E reduzieren und so die Wirkung verlängern. Kombination in Standarddosen ist unkritisch; Gesamte antioxidative Einnahme im Blick behalten.
View details →Quercetin und Resveratrol beeinflussen in Kombination gegenseitig ihre Bioverfügbarkeit deutlich. Plasmaspiegel beider Substanzen können in speziellen Formulierungen stark variieren.
Quercetin und Resveratrol können sich in ihrer Bioverfügbarkeit gegenseitig beeinflussen und CYP-Enzyme hemmen. Bei Medikamenten-Einnahme Rücksprache mit dem Arzt halten; Standarddosen (Quercetin ≤500mg, Resveratrol ≤150mg) ohne bekannte Risiken.
View details →Quercetin enhances catechin bioavailability by competing with catecholamine-metabolizing enzymes, reducing catechin degradation.
Quercetin kann durch COMT-Hemmung die Aufnahme von Catechinen verbessern. Wer beide einnimmt, profitiert von erhöhter Bioverfügbarkeit; EGCG-Tagesmenge aus allen Quellen unter 800mg halten.
View details →Quercetin kann pro-inflammatorische Effekte von hochdosiertem Beta-Carotin abschwächen. Die Kombination ist bei üblichen Dosierungen eher vorteilhaft als risikoreich.
Quercetin kann entzündungsfördernde Effekte von hochdosiertem Beta-Carotin abschwächen. Standarddosen beider Substanzen (Quercetin ≤500mg, Beta-Carotin ≤3mg) zeigen keine problematische Wechselwirkung.
View details →Quercetin kinetics differ substantially between free aglycone and glycoside (rutin) forms.
Quercetin-Aglykon und Rutin (Quercetin-Glykosid) zeigen unterschiedliche Resorptionsgeschwindigkeiten und ergänzen sich zeitlich. Gesamtzufuhr an Quercetin-Verbindungen auf ≤500mg/Tag begrenzen.
View details →What Experts Say
“polyphenols such as quercetin as well as EGCG can transport zinc cations across the plasma membrane independently of plasma membrane zinc transporters”
Rhonda Patrick explains quercetin's role as a zinc ionophore, noting it can transport zinc ions across cell membranes independently of standard zinc transporters. Zinc then inhibits RNA-dependent RNA polymerase — a key enzyme in RNA virus replication. She also discusses in vitro antiviral activity against SARS-CoV-1 and broader coronaviruses.
Scientific Sources
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- Inhibitory Effect of Flavonoids on Low‐Density Lipoprotein Peroxidation Catalyze (2000)
- Inhibition of mammalian 15-lipoxygenase-dependent lipid peroxidation in low-dens (1998)
- Modulation of human keratinocyte responses to solar UV by plant polyphenols as a (2013)
- Inhibition of photooxidation of alpha-tocopherol by quercetin in human blood cel (1991)
- [Effects of quercetin on photosensitized oxidation of alpha-tocopherol in human (1990)
- Enhanced Oral Bioavailability and Improved Biological Activities of a Quercetin/ (2020)
- Differential protective effects of red wine polyphenol extracts (RWEs) on colon (2014)
- Synergism between resveratrol and other phytochemicals: implications for obesity (2011)
- Resveratrol and quercetin cooperate to induce senescence‐like growth arrest in C (2009)
- Combination of Resveratrol and Quercetin Causes Cell Growth Inhibition, DNA Dama (2020)
- Quercetin and fisetin enhanced the small intestine cellular uptake and plasma le (2018)
- Radical-scavenging and Anti-inflammatory Activity of Quercetin and Related Compo (2015)
- MicroRNA-based regulatory mechanisms underlying the synergistic antioxidant acti (2020)
- Antimicrobial activity of Cannabis sativa, Thuja orientalis and Psidium guajava (2018)
- GRID and docking analyses reveal a molecular basis for flavonoid inhibition of S (2015)
- Interactions of beta-carotene and flavonoids on the secretion of pro-inflammator (2009)
- Effects of quercetin on beta-apo-8'-carotenal-induced DNA damage and cytochrome (2006)
- Flavonoids suppresses the enhancing effect of beta-carotene on DNA damage induce (2006)
- Ingested quercetin but not rutin increases accumulation of hepatic beta-carotene (2010)
- Pro-oxidative effect of beta-carotene and the interaction with flavonoids on UVA (2005)
- Pharmacokinetics of quercetin from quercetin aglycone and rutin in healthy volun (2000)
- Rutin (quercetin rutinoside) induced protein-energy malnutrition in chronic kidn (2013)
- Chemotherapeutic Efficacy Enhancement in P-gp-Overexpressing Cancer Cells by Fla (2020)
- Enzyme-assisted development of biofunctional polyphenol-enriched buckwheat prote (2019)
- Neurohormetic responses of quercetin and rutin in a cell line over-expressing th (2016)
- NIH Dietary Supplement Label Database (DSLD)
- PubChem Compound 5280343
Frequently Asked Questions
What is Quercetin used for?
Quercetin (C15H10O7) is a dietary flavonol with antioxidant, anti-inflammatory (COX-2/NF-κB inhibition), antiviral, and senolytic properties.
What is the recommended dosage for Quercetin?
500 mg. Any time. Can take on empty stomach.
Does Quercetin interact with other supplements?
Quercetin has 33 verified interactions. Top: Vitamin E (Tocopherol), Resveratrol.
When is the best time to take Quercetin?
Any time. Can take on empty stomach.
Is Quercetin safe to combine with other supplements?
Always check interactions before combining supplements. Use VitalStack to verify your full stack for free.
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