3,3',4'5,7-Pentahydroxyflavone, Bioflavonoid, Bioflavonoid Complex, Bioflavonoid Concentrate, Bioflavonoid Extract, Bioflavonoïde, Bioflavonoïde de Citron, Bioflavonoïdes de Citron, Citrus Bioflavones, Citrus Bioflavonoid, Citrus Bioflavonoids, Citrus Bioflavonoid Extract, Citrus Flavones, Citrus Flavonoids, Complexe de Bioflavonoïde, Concentré de Bioflavonoïde, Extrait de Bioflavonoïde, Extrait de Bioflavonoïdes de Citron, Flavones de Citron, Flavonoid, Flavonoïde, Meletin, Mélétine, Quercetina, Quercétine, Sophretin, Sophrétine.<br/><br/>
Overview InformationQuercetin is a plant pigment (flavonoid). It is found in many plants and foods, such as red wine, onions, green tea, apples, berries, Ginkgo biloba, St. John's wort, American elder, and others. Buckwheat tea has a large amount of quercetin. People use quercetin as a medicine.
Quercetin is most commonly taken by mouth to treat conditions of the heart and blood vessels and prevent cancer. It is also used for arthritis, bladder infections, and diabetes. But there is limited scientific evidence to support these uses.
How does it work?Quercetin has antioxidant and anti-inflammatory effects which might help reduce inflammation, kill cancer cells, control blood sugar, and help prevent heart disease.
Uses & Effectiveness
Possibly Ineffective for
- Exercise performance. Taking quercetin before exercise does not appear to improve fatigue, reduce muscle soreness, or decrease swelling.
Insufficient Evidence for
- Autism. Early research shows that taking a product containing quercetin and other ingredients might improve behavior and social interactions in children with autism.
- Enlarged prostate (benign prostatic hyperplasia or BPH). Early research shows that taking a product containing quercetin, beta-sitosterol, and saw palmetto doesn't help with urination and other symptoms in men with BPH.
- Heart disease. Some research suggests that eating foods rich in quercetin, such as tea, onions and apples, may reduce the risk of death due to heart disease in elderly men. However, taking a daily quercetin supplement does not seem to improve heart disease risk factors in people who are healthy.
- Diabetes. Early research shows that taking a combination of quercetin, myricetin, and chlorogenic acid helps to lower blood sugar in people with diabetes who are not taking antidiabetes drugs. Taking the same combination also seems to benefit people with diabetes who are already taking metformin.
- Exercise-induced respiratory infections. Early research shows that taking quercetin may reduce the chance for upper respiratory infections after heavy exercise.
- High cholesterol. Short-term use of quercetin does not appear to lower "bad cholesterol" (low-density lipoprotein (LDL) cholesterol) or total cholesterol, or to raise "good cholesterol" (high-density lipoprotein (HDL) cholesterol). But most of the studies conducted have been small and included people without high cholesterol. It's unclear if quercetin would show benefit in only people with high cholesterol.
- High blood pressure. Early research suggests that taking quercetin produces a small decrease in blood pressure in people with untreated, mild high blood pressure. It's unclear if this reduction in blood pressure is clinically meaningful.
- Kidney transplantation. Some research suggests that taking a product containing quercetin and curcumin, starting within 24 hours of kidney transplantation, improves early function of the transplanted kidney when taken in combination with anti-rejection drugs.
- Lung cancer. Higher intake of quercetin as part of the diet has been linked with a lower risk of lung cancer in people who smoke.
- Inflamed mouth sores (oral mucositis). Early research suggests that taking quercetin does not prevent mouth sores caused by cancer drugs.
- Ovarian cancer. One population study found no link between quercetin intake from the diet and the chance of ovarian cancer.
- Pancreatic cancer. Some research suggests that eating high amounts of quercetin in the diet might reduce the chance of developing pancreatic cancer, especially in men who smoke.
- An ovary disorder known as polycystic ovary syndrome (PCOS). Research shows that taking quercetin improves hormone levels in women with PCOS. It also seems to improve how sensitive the body is to insulin. But it's unclear if these changes lead to improvements in symptoms of PCOS such as irregular periods.
- Prostate pain and swelling (inflammation). Taking quercetin by mouth seems to reduce pain and improve quality of life, but doesn't seem to help urination problems in men with ongoing prostate problems that aren't due to infection.
- Rheumatoid arthritis (RA). Research shows that taking quercetin reduces pain and stiffness in women with RA. But it doesn't seem to reduce the number of swollen or tender joints.
- Painful urination due to problems with the urethra (urethral syndrome). Early research shows that taking a product containing quercetin, bromelain, chondroitin sulfate, gotu kola, rhodiola, and barbed skullcap helps reduce how often people with urethral syndrome need to urinate.
- Urinary tract infections (UTIs). Early research suggests that taking a combination of hyaluronic acid, chondroitin sulfate, curcumin, and quercetin by mouth, and applying estrogen to the vagina, helps to prevent UTIs in women who get them often. The quercetin product also works without the estrogen, but not as well.
- Chronic fatigue syndrome (CFS).
- "Hardening of the arteries" (atherosclerosis).
- Hay fever (allergic rhinitis).
- Pain and swelling (inflammation).
- Stomach and intestinal ulcers.
- Viral infections.
- Other conditions.
Side Effects & SafetyQuercetin is POSSIBLY SAFE for most people when taken by mouth short-term. Quercetin has been safely used in amounts up to 500 mg twice daily for 12 weeks. It is not known if long-term use or higher doses are safe.
When taken by mouth, quercetin can cause headache and tingling of the arms and legs. Very high doses might cause kidney damage.
When given intravenously (by IV) in appropriate amounts (less than 722 mg), quercetin is POSSIBLY SAFE. Side effects may include flushing, sweating, nausea, vomiting, difficulty breathing, or pain at the injection site. But larger amounts given by IV are POSSIBLY UNSAFE . There have been reports of kidney damage at higher doses.
Special Precautions & Warnings:Pregnancy and breast-feeding : Not enough is known about the use of quercetin during pregnancy and breast-feeding. Stay on the safe side and avoid use.
Kidney problems : Quercetin might make kidney problems worse. Don't use quercetin if you have kidney problems.
Be cautious with this combination
Antibiotics (Quinolone antibiotics) interacts with QUERCETIN
Taking quercetin along with some antibiotics might decrease the effectiveness of some antibiotics. Some scientists think that quercetin might prevent some antibiotics from killing bacteria. But it's too soon to know if this is a big concern.<br><nb>Some of these antibiotics that might interact with quercetin include ciprofloxacin (Cipro), enoxacin (Penetrex), norfloxacin (Chibroxin, Noroxin), sparfloxacin (Zagam), trovafloxacin (Trovan), and grepafloxacin (Raxar).
Cyclosporin (Neoral, Sandimmune) interacts with QUERCETIN
Cyclosporin (Neoral, Sandimmune) is changed and broken down by the liver. Quercetin might decrease how quickly the liver breaks down cyclosporin (Neoral, Sandimmune). Taking quercetin might increase the effects and side effects of this medication. Before taking quercetin talk to your healthcare provider if you take cyclosporin (Neoral, Sandimmune).
Medications changed by the liver (Cytochrome P450 2C8 (CYP2C8) substrates) interacts with QUERCETIN
Some medications are changed and broken down by the liver. Quercetin might decrease how quickly the liver breaks down some medications. Taking quercetin along with these medications that are changed by the liver might increase the effects and side effects of your medication. Before taking quercetin talk to your healthcare provider if you take any medications that are changed by the liver.<br><nb>Some medications that are changed by the liver include paclitaxel (Taxol), rosiglitazone (Avandia), amiodarone (Cordarone), docetaxel (Taxotere), repaglinide (Prandin), verapamil (Calan, Isoptin, Verelan), and others.
Medications changed by the liver (Cytochrome P450 2C9 (CYP2C9) substrates) interacts with QUERCETIN
Some medications are changed and broken down by the liver. Quercetin might decrease how quickly the liver breaks down some medications. Taking quercetin along with these medications that are changed by the liver might increase the effects and side effects of your medication. Before taking quercetin talk to your healthcare provider if you take any medications that are changed by the liver.<br><nb>Some medications that are changed by the liver include celecoxib (Celebrex), diclofenac (Voltaren), fluvastatin (Lescol), glipizide (Glucotrol), ibuprofen (Advil, Motrin), irbesartan (Avapro), losartan (Cozaar), phenytoin (Dilantin), piroxicam (Feldene), tamoxifen (Nolvadex), tolbutamide (Tolinase), torsemide (Demadex), warfarin (Coumadin), and others.
Medications changed by the liver (Cytochrome P450 2D6 (CYP2D6) substrates) interacts with QUERCETIN
Some medications are changed and broken down by the liver. Quercetin might decrease how quickly the liver breaks down some medications. Taking quercetin along with these medications that are changed by the liver might increase the effects and side effects of your medication. Before taking quercetin talk to your healthcare provider if you take any medications that are changed by the liver.<br><nb>Some medications that are changed by the liver include amitriptyline (Elavil), codeine, flecainide (Tambocor), haloperidol (Haldol), imipramine (Tofranil), metoprolol (Lopressor, Toprol XL), ondansetron (Zofran), paroxetine (Paxil), risperidone (Risperdal), tramadol (Ultram), venlafaxine (Effexor), and others.
Medications changed by the liver (Cytochrome P450 3A4 (CYP3A4) substrates) interacts with QUERCETIN
Some medications are changed and broken down by the liver. Quercetin might decrease how quickly the liver breaks down some medications. Taking quercetin along with these medications that are changed by the liver might increase the effects and side effects of your medication. Before taking quercetin talk to your healthcare provider if you take any medications that are changed by the liver.<br><nb>Some medications that are changed by the liver include lovastatin (Mevacor), clarithromycin (Biaxin), cyclosporine (Neoral, Sandimmune), diltiazem (Cardizem), estrogens, indinavir (Crixivan), triazolam (Halcion), verapamil (Calan, Isoptin, Verelan), alfentanil (Alfenta), fentanyl (Sublimaze), losartan (Cozaar), fluoxetine (Prozac), midazolam (Versed), omeprazole (Prilosec), lansoprazole (Prevacid), ondansetron (Zofran), propranolol (Inderal), fexofenadine (Allegra), amitriptyline (Elavil), amiodarone (Cordarone), citalopram (Celexa), sertraline (Zoloft), ketoconazole (Nizoral), itraconazole (Sporanox), and numerous others.
Medications moved by pumps in cells (P-glycoprotein Substrates)) interacts with QUERCETIN
Some medications are moved by pumps in cells. Quercetin might make these pumps less active and increase how much of some medications get absorbed by the body. This might cause more side effects from some medications.<br><nb>Some medications that are moved by these pumps include diltiazem (Cardizem), verapamil (Calan, Isoptin, Verelan), digoxin (Lanoxin) cyclosporine (Neoral, Sandimmune), saquinavir (Invirase), amprenavir (Agenerase), nelfinavir (Viracept), loperamide (Imodium), quinidine, paclitaxel (Taxol), vincristine, etoposide (VP16, VePesid), cimetidine (Tagamet), ranitidine (Zantac), fexofenadine (Allegra), ketoconazole (Nizoral), itraconazole (Sporanox), and others.
The appropriate dose of quercetin depends on several factors such as the user's age, health, and several other conditions. At this time there is not enough scientific information to determine an appropriate range of doses for quercetin. Keep in mind that natural products are not always necessarily safe and dosages can be important. Be sure to follow relevant directions on product labels and consult your pharmacist or physician or other healthcare professional before using.
- Loke, W. M., Hodgson, J. M., Proudfoot, J. M., McKinley, A. J., Puddey, I. B., and Croft, K. D. Pure dietary flavonoids quercetin and (-)-epicatechin augment nitric oxide products and reduce endothelin-1 acutely in healthy men. Am J Clin Nutr 2008;88(4):1018-1025. View abstract.
- Mayer, B., Schumacher, M., Brandstatter, H., Wagner, F. S., and Hermetter, A. High-throughput fluorescence screening of antioxidative capacity in human serum. Anal.Biochem 10-15-2001;297(2):144-153. View abstract.
- McAnulty, S. R., McAnulty, L. S., Nieman, D. C., Quindry, J. C., Hosick, P. A., Hudson, M. H., Still, L., Henson, D. A., Milne, G. L., Morrow, J. D., Dumke, C. L., Utter, A. C., Triplett, N. T., and Dibarnardi, A. Chronic quercetin ingestion and exercise-induced oxidative damage and inflammation. Appl.Physiol Nutr Metab 2008;33(2):254-262. View abstract.
- Murakami, A., Ashida, H., and Terao, J. Multitargeted cancer prevention by quercetin. Cancer Lett. 10-8-2008;269(2):315-325. View abstract.
- Nieman, D. C. Immunonutrition support for athletes. Nutr.Rev. 2008;66(6):310-320. View abstract.
- Rayalam, S., Della-Fera, M. A., and Baile, C. A. Phytochemicals and regulation of the adipocyte life cycle. J Nutr Biochem. 2008;19(11):717-726. View abstract.
- Stavric, B. Quercetin in our diet: from potent mutagen to probable anticarcinogen. Clin.Biochem. 1994;27(4):245-248. View abstract.
- Terao, J., Kawai, Y., and Murota, K. Vegetable flavonoids and cardiovascular disease. Asia Pac.J Clin Nutr 2008;17 Suppl 1:291-293. View abstract.
- Walle, T., Walle, U. K., and Halushka, P. V. Carbon dioxide is the major metabolite of quercetin in humans. J.Nutr. 2001;131(10):2648-2652. View abstract.
- Wiczkowski, W., Romaszko, J., Bucinski, A., Szawara-Nowak, D., Honke, J., Zielinski, H., and Piskula, M. K. Quercetin from shallots (Allium cepa L. var. aggregatum) is more bioavailable than its glucosides. J Nutr 2008;138(5):885-888. View abstract.
- Ahrens MJ, Thompson DL. Effect of emulin on blood glucose in type 2 diabetics. J Med Food. 2013;16(3):211-5. View abstract.
- Anon. Quercetin. Alt Med Rev 1998;3:140-3.
- Bobe G, Weinstein SJ, Albanes D, et al. Flavonoid intake and risk of pancreatic cancer in male smokers (Finland). Cancer Epidemiol Biomarkers Prev 2008;17:553-62. View abstract.
- Choi JS, Choi BC, Choi KE. Effect of quercetin on the pharmacokinetics of oral cyclosporine. Am J Health Syst Pharm 2004;61:2406-9. View abstract.
- Choi JS, Jo BW, Kim YC. Enhanced paclitaxel bioavailability after oral administration of paclitaxel or prodrug to rats pretreated with quercetin. Eur J Pharm Biopharm 2004;57:313-8. View abstract.
- Conquer JA, Maiani G, Azzini E, et al. Supplementation with quercetin markedly increases plasma quercetin concentration without effect on selected risk factors for heart disease in healthy subjects. J Nutr 1998;128:593-7. View abstract.
- de Pascual-Teresa S, Johnston KL, DuPont MS, et al. Quercetin metabolites downregulate cyclooxygenase-2 transcription in human lymphocytes ex vivo but not in vivo. J Nutr 2004;134:552-7. View abstract.
- de Vries JH, Hollman PC, van Amersfoort I, et al. Red wine is a poor source of bioavailable flavonols in men. J Nutr 2001;131:745-8. View abstract.
- Di Bari L, Ripoli S, Pradhan S, Salvadori P. Interactions between quercetin and warfarin for albumin binding: A new eye on food/drug interference. Chirality 2010;22:593-6. View abstract.
- DiCenzo R, Frerichs V, Larppanichpoonphol P, et al. Effect of quercetin on the plasma and intracellular concentrations of saquinavir in healthy adults. Pharmacotherapy 2006;26:1255-61. View abstract.
- Duan KM, Wang SY, Ouyang W, Mao YM, Yang LJ. Effect of quercetin on CYP3A activity in Chinese healthy participants. J Clin Pharmacol 2012;52(6):940-6. View abstract.
- Edwards RL, Lyon T, Litwin SE, et al. Quercetin reduces blood pressure in hypertensive subjects. J Nutr 2007;137:2405-11. View abstract.
- El Attar TM, Virji AS. Modulating effect of resveratrol and quercetin on oral cancer cell growth and proliferation. Anticancer Drugs 1999;10:187-93. View abstract.
- Erlund I, Freese R, Marniemi J, et al. Bioavailability of quercetin from berries and the diet. Nutr Cancer 2006;54:13-7. View abstract.
- Erlund I, Kosonen T, Alfthan G, et al. Pharmacokinetics of quercetin from quercetin aglycone and rutin in healthy volunteers. Eur J Clin Pharmacol 2000;56:545-53.. View abstract.
- Ferry DR, Smith A, Malkhandi J, et al. Phase I clinical trial of the flavonoid quercetin: Pharmacokinetics and evidence for in vivo tyrosine kinase inhibition. Clin Cancer Res 1996;2:659-67.. View abstract.
- Gates MA, Tworoger SS, Hecht JL, et al. A prospective study of dietary flavonoid intake and incidence of epithelial ovarian cancer. Int J Cancer 2007;121:2225-32. View abstract.
- Goldberg DM, Yan J, Soleas GJ. Absorption of three wine-related polyphenols in three different matrices by healthy subjects. Clin Biochem 2003;36:79-87.. View abstract.
- Guo Y, Mah E, Davis CG, et al. Dietary fat increases quercetin bioavailability in overweight adults. Mol Nutr Food Res 2013;57(5):896-905. View abstract.
- Harwood M, Danielewska-Nikiel B, Borzelleca JF, et al. A critical review of the data related to the safety of quercetin and lack of evidence of in vivo toxicity, including lack of genotoxic / carcinogenic properties. Food Chem Toxicol 2007;45:2179-205. View abstract.
- Hertog MG, Feskens EJ, Hollman PC, et al. Dietary antioxidant flavonoids and risk of coronary heart disease: the Zutphen Elderly Study. Lancet 1993;342:1007-1011. View abstract.
- Huang Z, Fasco MJ, Kaminsky LS. Inhibition of estrone sulfatase in human liver microsomes by quercetin and other flavonoids. J Steroid Biochem Mol Biol 1997;63:9-15. View abstract.
- Hubbard GP, Wolffram S, Lovegrove JA, Gibbins JM. Ingestion of quercetin inhibits platelet aggregation and essential components of the collagen-stimulated platelet activation pathway in humans. J Thromb Haemost 2004;2:2138-45. View abstract.
- Janssen K, Mensink RP, Cox FJ, et al. Effects of the flavonoids quercetin and apigenin on hemostasis in healthy volunteers: results from an in vitro and a dietary supplement study. Am J Clin Nutr 1998;67:255-62. View abstract.
- Javadi F, Ahmadzadeh A, Eghtesadi S, et al. The effect of quercetin on inflammatory factors and clinical symptoms in women with rheumatoid arthritis: A double-blind, randomized controlled trial. J Am Coll Nutr. 2017;36(1):9-15. View abstract.
- Kim KA, Park PW, Kim HK, et al. Effect of quercetin on the pharmacokinetics of rosiglitazone, a CYP2C8 substrate, in healthy subjects. J Clin Pharmacol 2005;45:941-6. View abstract.
- Koga T, Meydani M. Effect of plasma metabolites of (+)-catechin and quercetin on monocyte adhesion to human aortic endothelial cells. Am J Clin Nutr 2001;73:941-8.. View abstract.
- Kooshyar MM, Mozafari PM, Amirchaghmaghi M, et al. A randomized placebo-controlled double blind clinical trial of quercetin in the prevention and treatment of chemotherapy-induced oral mucositis. J Clin Diagn Res. 2017;11(3):ZC46-ZC50. View abstract.
- Kuo SM, Leavitt PS, Lin CP. Dietary flavonoids interact with trace metals and affect metallothionein level in human intestinal cells. Biol Trace Elem Res 1998;62:135-53. View abstract.
- Larson A, Witman MA, Guo Y, et al. Acute, quercetin-induced reductions in blood pressure in hypertensive individuals are not secondary to lower plasma angiotensin-converting enzyme activity or endothelin-1: nitric oxide. Nutr Res. 2012;32(8):557-64. View abstract.
- Lean ME, Noroozi M, Kelly I. Dietary flavonols protect diabetic human lymphocytes against oxidative damage to DNA. Diabetes 1999;48:176-81. View abstract.
- McAnlis GT, McEneny J, Pearce J, Young IS. Absorption and antioxidant effects of quercetin from onions, in man. Eur J Clin Nutr 1999;53:92-6. View abstract.
- Miodini P, Fioravanti L, Di Fronzo G, Cappelletti V. The two phyto-oestrogens genistein and quercetin exert different effects on oestrogen receptor function. Br J Cancer 1999;80:1150-5. View abstract.
- Murota K, Terao J. Antioxidative flavonoid quercetin: implication of its intestinal absorption and metabolism. Arch Biochem Biophys 2003;417:12-7. View abstract.
- Nemeth K, Piskula MK. Food content, processing, absorption and metabolism of onion flavonoids. Crit Rev Food Sci Nutr 2007;47:397-409. View abstract.
- Nguyen MA, Staubach P, Wolffram S, Langguth P. Effect of single-dose and short-term administration of quercetin on the pharmacokinetics of talinolol in humans - Implications for the evaluation of transporter-mediated flavonoid-drug interactions. Eur J Pharm Sci 2014;61:54-60. View abstract.
- Barna, M., Kucera, A., Hladicova, M., and Kucera, M. [Wound healing effects of a Symphytum herb extract cream (Symphytum x uplandicum NYMAN: ): results of a randomized, controlled double-blind study]. Wien.Med.Wochenschr. 2007;157(21-22):569-574. View abstract.
- Barna, M., Kucera, A., Hladikova, M., and Kucera, M. Randomized double-blind study: wound-healing effects of a Symphytum herb extract cream (Symphytumxuplandicum Nyman) in children. Arzneimittelforschung. 2012;62(6):285-289. View abstract.
- Barthomeuf, C. M., Debiton, E., Barbakadze, V. V., and Kemertelidze, E. P. Evaluation of the dietetic and therapeutic potential of a high molecular weight hydroxycinnamate-derived polymer from Symphytum asperum Lepech. Regarding its antioxidant, antilipoperoxidant, antiinflammatory, and cytotoxic properties. J Agric.Food Chem 2001;49(8):3942-3946. View abstract.
- Behninger, C., Abel, G., Roder, E., Neuberger, V., and Goggelmann, W. [Studies on the effect of an alkaloid extract of Symphytum officinale on human lymphocyte cultures]. Planta Med. 1989;55(6):518-522. View abstract.
- Bleakley, C. M., McDonough, S. M., and MacAuley, D. C. Some conservative strategies are effective when added to controlled mobilisation with external support after acute ankle sprain: a systematic review. Aust.J Physiother. 2008;54(1):7-20. View abstract.
- Couet, C. E., Crews, C., and Hanley, A. B. Analysis, separation, and bioassay of pyrrolizidine alkaloids from comfrey (Symphytum officinale). Nat.Toxins. 1996;4(4):163-167. View abstract.
- D'Anchise, R., Bulitta, M., and Giannetti, B. Comfrey extract ointment in comparison to diclofenac gel in the treatment of acute unilateral ankle sprains (distortions). Arzneimittelforschung. 2007;57(11):712-716. View abstract.
- Giannetti, B. M., Staiger, C., Bulitta, M., and Predel, H. G. Efficacy and safety of comfrey root extract ointment in the treatment of acute upper or lower back pain: results of a double-blind, randomised, placebo controlled, multicentre trial. Br.J Sports Med. 2010;44(9):637-641. View abstract.
- Grube, B., Grunwald, J., Krug, L., and Staiger, C. Efficacy of a comfrey root (Symphyti offic. radix) extract ointment in the treatment of patients with painful osteoarthritis of the knee: results of a double-blind, randomised, bicenter, placebo-controlled trial. Phytomedicine. 2007;14(1):2-10. View abstract.
- Gyorik, S. and Stricker, H. Severe pulmonary hypertension possibly due to pyrrolizidine alkaloids in polyphytotherapy. Swiss.Med.Wkly. 4-4-2009;139(13-14):210-211. View abstract.
- Hirono, I., Mori, H., and Haga, M. Carcinogenic activity of Symphytum officinale. J Natl.Cancer Inst 1978;61(3):865-869. View abstract.
- Johnson, B. M., Bolton, J. L., and van Breemen, R. B. Screening botanical extracts for quinoid metabolites. Chem Res Toxicol 2001;14(11):1546-1551. View abstract.
- Nieman DC, Henson DA, Davis JM, et al. Quercetin ingestion does not alter cytokine changes in athletes competing in the Western States Endurance Run. J Interferon Cytokine Res 2007;27:1003-11. View abstract.
- Nieman DC, Henson DA, Davis JM, et al. Quercetin's influence on exercise-induced changes in plasma cytokines and muscle and leukocyte cytokine mRNA. J Appl Physiol 2007;103:1728-35. View abstract.
- Nieman DC, Henson DA, Gross SJ, et al. Quercetin reduces illness but not immune perturbations after intensive exercise. Med Sci Sports Exerc 2007;39:1561-9. View abstract.
- Nishijima T, Takida Y, Saito Y, Ikeda T, Iwai K. Simultaneous ingestion of high-methoxy pectin from apple can enhance absorption of quercetin in human subjects. Br J Nutr. 2015 May 28;113(10):1531-8. View abstract.
- Nöthlings U, Murphy SP, Wilkens LR, et al. Flavonols and pancreatic cancer risk: the multiethnic cohort study. Am J Epidemiol 2007;166:924-31. View abstract.
- Obach RS. Inhibition of human cytochrome P450 enzymes by constituents of St. John's wort, an herbal preparation used in the treatment of depression. J Pharmacol Exp Ther 2000;294:88-95. View abstract.
- Otsuka H, Inaba M, Fujikura T, Kunitomo M. Histochemical and functional characteristics of metachromatic cells in the nasal epithelium in allergic rhinitis: studies of nasal scrapings and their dispersed cells. J Allergy Clin Immunol 1995;96:528-36.. View abstract.
- Palleschi G, Carbone A, Ripoli A, et al. A prospective study to evaluate the efficacy of Cistiquer in improving lower urinary tract symptoms in females with urethral syndrome. Minerva Urol Nefrol. 2014;66(4):225-32. View abstract.
- Pelletier DM, Lacerte G, Goulet ED. Effects of quercetin supplementation on endurance performance and maximal oxygen consumption: a meta-analysis. Int J Sport Nutr Exerc Metab 2013;23(1):73-82. View abstract.
- Perez-Vizcaino F, Duarte J, Andriantsitohaina R. Endothelial function and cardiovascular disease: effects of quercetin and wine polyphenols. Free Radic Res 2006;40:1054-65. View abstract.
- Rachkauskas GS. The efficacy of enterosorption and a combination of antioxidants in schizophrenics. Lik Sprava 1998;4:122-4. View abstract.
- Rezvan N, Moini A, Janani L, et al. Effects of quercetin on adiponectin-mediated insulin sensitivity in polycystic ovary syndrome: A randomized placebo-controlled double-blind clinical trial. Horm Metab Res. 2017;49(2):115-121. View abstract.
- Sahebkar A. Effects of quercetin supplementation on lipid profile: A systematic review and meta-analysis of randomized controlled trials. Crit Rev Food Sci Nutr. 2017;57(4):666-676. View abstract.
- Serban MC, Sahebkar A, Zanchetti A, et al; Lipid and Blood Pressure Meta-analysis Collaboration (LBPMC) Group. Effects of quercetin on blood pressure: A systematic review and meta-analysis of randomized controlled trials. J Am Heart Assoc. 2016;5(7). pii: e002713. View abstract.
- Sesink AL, O'Leary KA, Hollman PC. Quercetin glucuronides but not glucosides are present in human plasma after consumption of quercetin-3-glucoside or quercetin-4'-glucoside. J Nutr 2001;131:1938-41.. View abstract.
- Sharp MA, Hendrickson NR, Staab JS, et al. Effects of short-term quercetin supplementation on soldier performance. J Strength Cond Res 2012;26 Suppl 2:S53-60. View abstract.
- Shoskes D, Lapierre C, Cruz-Corerra M, et al. Beneficial effects of the bioflavonoids curcumin and quercetin on early function in cadaveric renal transplantation: a randomized placebo controlled trial. Transplantation 2005;80:1556-9. View abstract.
- Shoskes DA, Zeitlin SI, Shahed A, Rajfer J. Quercetin in men with category III chronic prostatitis: A preliminary prospective, double-blind, placebo-controlled trial. Urol 1999;54:960-3. View abstract.
- Starvic B. Quercetin in our diet: from potent mutagen to probable anticarcinogen. Clin Biochem 1994;27:245-8.
- Suardi N, Gandaglia G, Nini A, et al. Effects of Difaprost® on voiding dysfunction, histology and inflammation markers in patients with benign prostatic hyperplasia who are candidates for surgical treatment. Minerva Urol Nefrol. 2014;66(2):119-25. View abstract.
- Taliou A, Zintzaras E, Lykouras L, Francis K. An open-label pilot study of a formulation containing the anti-inflammatory flavonoid luteolin and its effects on behavior in children with autism spectrum disorders. Clin Ther. 2013;35(5):592-602. View abstract.
- Torella M, Del Deo F, Grimaldi A, et al. Efficacy of an orally administered combination of hyaluronic acid, chondroitin sulfate, curcumin and quercetin for the prevention of recurrent urinary tract infections in postmenopausal women. Eur J Obstet Gynecol Reprod Biol. 2016;207:125-128. View abstract.
- Vaclavikova R, Horsky S, Simek P, Gut I. Paclitaxel metabolism in rat and human liver microsomes is inhibited by phenolic antioxidants. Naunyn Schmiedebergs Arch Pharmacol 2003;368:200-9. View abstract.
- Walle T, Otake Y, Walle UK, Wilson FA. Quercetin glucosides are completely hydrolyzed in ileostomy patients before absorption. J Nutr 2000;130:2658-61.. View abstract.
- Wiseman H. The bioavailability of non-nutrient plant factors: dietary flavonoids and phyto-oestrogens. Proc Nutr Soc 1999;58:139-46. View abstract.
- Woo HD, Kim J. Dietary flavonoid intake and smoking-related cancer risk: a meta-analysis. PLoS One. 2013;8(9):e75604. View abstract.
- Wu LX, Guo CX, Chen WQ, et al. Inhibition of the organic anion-transporting polypeptide 1B1 by quercetin: an in vitro and in vivo assessment. Br J Clin Pharmacol 2012;73(5):750-7. View abstract.
Have you ever purchased QUERCETIN?
Did you or will you purchase this product in-store or online?
Where did you or where do you plan to purchase this product?
Where did you or where do you plan to purchase this product?
What factors influenced or will influence your purchase? (check all that apply)
Where did you or where do you plan to purchase this product?
Do you buy vitamins online or instore?
What factors are most important to you? (check all that apply)