Quercetin

    Researchedby:
    Kamal Patel
    Last Updated: October 13, 2024

    Quercetin is the most well researched of all bioflavonoids. It is not actually that good of a supplement on its own, but is an interesting research topic. Tons of interactions, and synergistic with other bioflavonoids and increases absorption of Resveratrol and Green Tea Catechins.

    examine-databaseExamine Database

    Quercetin is most often used for Immunity & Infectious Disease. The Examine Database covers High Blood Pressure, Type 2 Diabetes, and 10 other conditions and goals.

    676 participants in 10 trials

    Summary

    Quercetin is a bioflavonoid found in fruits and vegetables, but highest levels are found in apples and onions.

    Like many other bioflavonoids, Quercetin has anti-oxidant, anti-artherogenic, and anti-carcinogenic properties. Quercetin is also neuroactive, with some of the same abilities as caffeine but less potent.

    There is a divide between the effects seen in quercetin in in vitro (cell cultured) studies and in vivo (in living) studies, with cell studies showing great results that are not that amazing in humans or animals. This is mostly due to quercetin having low oral bioavailability (low percentage of the compound is absorbed and put to use), but could also be due to in vitro studies using a form of quercetin called 'quercetin aglycone' whereas this particular form is never found in the blood, even after ingested, as it it gets changed in the liver.

    Many studies also note a high range of differences between people who ingest the same amount of quercetin, suggesting a large degree of variability is possible with supplementation.

    Quercetin has GRAS (Generally Recognized As Safe) status, and no side-effects have yet been noted in doses of a few grams a day in either humans or animals.

    What are other names for Quercetin

    Note that Quercetin is also known as:
    • Apple extract
    • 3 4 5 7-pentahydroxylflavone

    Dosage information

    Dosages of quercetin used are in the range of 12.5 to 25mg per kg body weight, which translates to a range of 1,136-2,272mg daily consumption of quercetin when in isolation.

    It is suggested to supplement with other bioflavonoids such as resveratrol, genistein, or green tea catechins to increase the potency synergistically and theoretically get the benefits at a reduced level of intake.

    When looking for quercetin, the form of dihydrate has the apparent best bioavailability followed by glycosides, aglycone, and finally rutinoside.

    Examine Database: Quercetin

    Research FeedRead all studies

    Research Breakdown

    Examine Database References

    1. Oxidative Stress Biomarkers - Boots AW, Drent M, de Boer VC, Bast A, Haenen GRQuercetin reduces markers of oxidative stress and inflammation in sarcoidosisClin Nutr.(2011 Aug)
    2. Oxidative Stress Biomarkers - Randi L. Edwards, Tiffany Lyon, Sheldon E. Litwin, Alexander Rabovsky, J. David Symons, and Thunder JaliliQuercetin Reduces Blood Pressure in Hypertensive SubjectsAmerican Society for Nutrition.()
    3. Blood Pressure - Egert S, Rimbach G, Müller MJNo evidence for a thermic effect of the dietary flavonol quercetin: a pilot study in healthy normal-weight womenEur J Appl Physiol.(2011 May)
    4. Rate of Perceived Exertion - Cheuvront SN, Ely BR, Kenefick RW, Michniak-Kohn BB, Rood JC, Sawka MNNo effect of nutritional adenosine receptor antagonists on exercise performance in the heatAm J Physiol Regul Integr Comp Physiol.(2009 Feb)
    5. Exercise-induced Stress Response - Kuennen M, Gillum T, Dokladny K, Bedrick E, Schneider S, Moseley PThermotolerance and heat acclimation may share a common mechanism in humansAm J Physiol Regul Integr Comp Physiol.(2011 Aug)
    6. Anaerobic Capacity - Abbey EL, Rankin JWEffect of quercetin supplementation on repeated-sprint performance, xanthine oxidase activity, and inflammationInt J Sport Nutr Exerc Metab.(2011 Apr)
    7. High-density lipoprotein (HDL) - Talirevic E, Jelena SQuercetin in the treatment of dyslipidemiaMed Arh.(2012)
    8. Sleep Quality - Bigelman KA, Chapman DP, Freese EC, Trilk JL, Cureton KJEffects of 6 weeks of quercetin supplementation on energy, fatigue, and sleep in ROTC cadetsMil Med.(2011 May)
    9. Quality of Life - Mantadaki AE, Linardakis M, Vafeiadi M, Anastasiou F, Tsatsakis A, Symvoulakis EKThe Impact of Three-Month Quercetin Intake on Quality of Life and Anxiety in Patients With Type II Diabetes Mellitus: An Early Data Analysis From a Randomized Controlled Trial.Cureus.(2024 Apr)
    10. HbA1c - Mantadaki AE, Linardakis M, Tsakiri M, Baliou S, Fragkiadaki P, Vakonaki E, Tzatzarakis MN, Tsatsakis A, Symvoulakis EKBenefits of Quercetin on Glycated Hemoglobin, Blood Pressure, PiKo-6 Readings, Night-Time Sleep, Anxiety, and Quality of Life in Patients with Type 2 Diabetes Mellitus: A Randomized Controlled Trial.J Clin Med.(2024 Jun 15)