Table of ContentsView AllTable of ContentsUsesSide EffectsPrecautionsDosageToxicityInteractionsHow to StoreFrequently Asked QuestionsSources & What to Look For
Table of ContentsView All
View All
Table of Contents
Uses
Side Effects
Precautions
Dosage
Toxicity
Interactions
How to Store
Frequently Asked Questions
Sources & What to Look For
Quercetin, a plant pigment, is said to have antioxidant and anti-inflammatory benefits. It is sometimes used to improve various health conditions such asheart disease,cancer,arthritis, andCOVID-19. However, there isn’t enough scientific evidence to support taking it for these conditions.
This chemical compound (flavonoid) is naturally found in foods including apples,onions, teas, berries, red wine, and herbs like Ginkgo biloba and St. John’s wort. It is also available in supplement form.
In the United States, the Food and Drug Administration (FDA) does not regulate supplements the way it regulates prescription drugs. That means some supplement products may not contain what the label says. Whenchoosing a supplement, look for independently tested products and consult a healthcare provider, registered dietitian nutritionist (RD or RDN), or pharmacist.
Purported Uses of Quercetin
Supplement Facts
Research on the potential health benefits of quercetin is often tested with animal models. Due to the lack of human research, there is not enough evidence to support quercetin’s use for the following:
Blood Pressure
A meta-analysis of human studies reviewed quercetin’s effects onblood pressurecontrol.
The analysis included seven trials consisting of 587 people overall. The results showed that quercetin supplementation significantly reducedsystolic and diastolic blood pressure. These reductions were mostly seen in people taking higher doses of 500 milligrams (mg) daily or greater.
Most studies in the analysis involved people with hypertension, except for one that included people with prehypertension and stage 1 disease.
Still, it is unclear if quercetin has much clinical benefit or would be useful as an add-on supplement for people with hypertension. Further research is needed to confirm the findings, look at other dosages, and study potential interactions with antihypertensive medications.
No supplement should replace standard medical care. Always check with your healthcare provider before starting any new supplement.
Inflammation
Some studies suggest quercetin may help lower inflammation in the body.
One small study examined quercetin’s possible effects on inflammation, disease severity, and symptoms in women withrheumatoid arthritis. The trial included 50 individuals who were sorted into a quercetin supplementation group or a placebo group for eight weeks. Quercetin users took 500 milligrams (mg) daily.
After eight weeks, those who received quercetin reported significantly reduced early morning stiffness, morning pain, and after-activity pain, according to the results. Quercetin users also had reduced markers of inflammation compared to those in the placebo group.
Still, more evidence is needed to recommend quercetin for this purpose. If you have pain, consult a healthcare provider for medical guidance.
Verywell / Anastasia Tretiak
What Are the Side Effects of Quercetin?
Consuming a supplement like quercetin may have potential side effects.
Quercetin is generally well-tolerated when used in appropriate amounts for short periods of time. Some possible side effects of quercetin include:
Check with your healthcare provider before taking quercetin. Remember to mention any medications you are taking and any pre-existing medical conditions.
Pregnant or lactating individuals, children, and people with kidney problems should not take quercetin in any form, as not enough research has been done in these populations.
Dosage: How Much Quercetin Should I Take?
Always speak with a healthcare provider before taking a supplement to ensure that the supplement and dosage are appropriate for your needs.
With medical supervision, quercetin has been safely used in amounts of up to 1 gram daily for 12 weeks.There is not enough evidence to know if it is safe for long-term use (longer than 12 weeks).
What Happens If I Take Too Much Quercetin?
As a general guideline, never take more than the manufacturer’s recommended dosage. If you experience side effects of any kind, stop taking quercetin and call your healthcare provider.
It is essential to carefully read the ingredient list and nutrition facts panel of a supplement to know which ingredients and how much of each ingredient is included. Please review this supplement label with your healthcare provider to discuss any potential interactions with foods, other supplements, and medications.
Medications
Quercetin may interact with the following medications:
Quercetin can also interact with cytochrome (CYP) enzymes and affect how the liver breaks down certain medications, including those known as:
It may also interact with certain drug transporters:
Ask your healthcare provider or pharmacist if you are taking a medication and are unsure if it belongs to any of the above-listed categories.
Herbs and Supplements
Quercetin may interact with herbs and supplements with blood-pressure-lowering effects (e.g., andrographis, casein peptides, niacin) or those that lower blood sugar (e.g., aloe, bitter melon, chromium).
This is not a complete list of drug and supplement interactions that may occur with quercetin. Tell your healthcare provider or pharmacist about all the substances you take, including prescription and over-the-counter (OTC) drugs, vitamins, and herbal supplements.
Benefits and Risks of Boldo Tea
How to Store Quercetin
Store quercetin according to manufacturer’s directions on the package. Discard as indicated on the packaging.
Frequently Asked QuestionsPregnant or breastfeeding individuals, children, and individuals with kidney problems should not take quercetin, as there is not enough information on its use in these populations.More research is needed to determine the exact health benefits of quercetin. Currently, there is not enough evidence to support its use for any health condition. Always talk to your healthcare provider before starting a new supplement.
Pregnant or breastfeeding individuals, children, and individuals with kidney problems should not take quercetin, as there is not enough information on its use in these populations.
More research is needed to determine the exact health benefits of quercetin. Currently, there is not enough evidence to support its use for any health condition. Always talk to your healthcare provider before starting a new supplement.
Sources of Quercetin & What to Look For
Food Sources of Quercetin
Food sources of quercetin include:
Does Oregano Tea Have Health Benefits?
Quercetin Supplements
Quercetin can often be purchased online or at health food stores.
When taking quercetin in supplement form, choosing a product that also contains papain and/orbromelainmay be beneficial. These plant-derived enzymes (fruit extracts) are shown to increase the intestine’s absorption of quercetin.
Supplements are classified as food products, not drugs. Therefore, it is important to note thatthe FDA does not strictly regulate them in the United States. Sometimes, a product may be contaminated or contain products other than those listed on the label. Also, remember that it is illegal for any company to market a dietary supplement product as a treatment or cure for a specific disease.
Summary
Quercetin is thought to have antioxidant and anti-inflammatory effects. While it’s been studied for various health conditions, more human studies are needed before taking quercetin for any health purpose. Although generally safe, quercetin can interact with many medications and supplements, so it’s important to talk to your healthcare provider before taking it.
7 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.MedlinePlus.Quercetin.National Institute of Health - Office of Dietary Supplements.Dietary supplements for exercise and athletic performance: Fact sheet for health professionals.Serban MC, Sahebkar A, Zanchetti A, et al.Effects of quercetin on blood pressure: A systematic review and meta-analysis of randomized controlled trials.J Am Heart Assoc. 2016;5(7). doi:10.1161/JAHA.115.002713Javadi 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. doi:10.1080/07315724.2016.1140093Anand David AV, Arulmoli R, Parasuraman S.Overviews of biological importance of quercetin: A bioactive flavonoid.Pharmacogn Rev. 2016;10(20):84-89. doi:10.4103/0973-7847.194044Mohos V, Fliszár-Nyúl E, Ungvári O, et al.Inhibitory effects of quercetin and its main methyl, sulfate, and glucuronic acid conjugates on cytochrome P450 enzymes, and on OATP, BCRP and MRP2 transporters.Nutrients. 2020;12(8):2306. doi:10.3390/nu12082306Memorial Sloan Kettering Cancer Center.Quercetin.Additional ReadingPapakyriakopoulou P, Velidakis N, Khattab E, Valsami G, Korakianitis I, Kadoglou NP.Potential pharmaceutical applications of quercetin in cardiovascular diseases.Pharmaceuticals. 2022;15(8):1019. doi:10.3390/ph15081019Zhang M, Swarts SG, Yin L, et al.Antioxidant properties of quercetin. In: LaManna JC, Puchowicz MA, Xu K, Harrison DK, Bruley DF, eds.Oxygen Transport to Tissue XXXII. Vol 701. Springer US; 2011:283-289. doi:10.1007/978-1-4419-7756-4_38
7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.MedlinePlus.Quercetin.National Institute of Health - Office of Dietary Supplements.Dietary supplements for exercise and athletic performance: Fact sheet for health professionals.Serban MC, Sahebkar A, Zanchetti A, et al.Effects of quercetin on blood pressure: A systematic review and meta-analysis of randomized controlled trials.J Am Heart Assoc. 2016;5(7). doi:10.1161/JAHA.115.002713Javadi 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. doi:10.1080/07315724.2016.1140093Anand David AV, Arulmoli R, Parasuraman S.Overviews of biological importance of quercetin: A bioactive flavonoid.Pharmacogn Rev. 2016;10(20):84-89. doi:10.4103/0973-7847.194044Mohos V, Fliszár-Nyúl E, Ungvári O, et al.Inhibitory effects of quercetin and its main methyl, sulfate, and glucuronic acid conjugates on cytochrome P450 enzymes, and on OATP, BCRP and MRP2 transporters.Nutrients. 2020;12(8):2306. doi:10.3390/nu12082306Memorial Sloan Kettering Cancer Center.Quercetin.Additional ReadingPapakyriakopoulou P, Velidakis N, Khattab E, Valsami G, Korakianitis I, Kadoglou NP.Potential pharmaceutical applications of quercetin in cardiovascular diseases.Pharmaceuticals. 2022;15(8):1019. doi:10.3390/ph15081019Zhang M, Swarts SG, Yin L, et al.Antioxidant properties of quercetin. In: LaManna JC, Puchowicz MA, Xu K, Harrison DK, Bruley DF, eds.Oxygen Transport to Tissue XXXII. Vol 701. Springer US; 2011:283-289. doi:10.1007/978-1-4419-7756-4_38
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
MedlinePlus.Quercetin.National Institute of Health - Office of Dietary Supplements.Dietary supplements for exercise and athletic performance: Fact sheet for health professionals.Serban MC, Sahebkar A, Zanchetti A, et al.Effects of quercetin on blood pressure: A systematic review and meta-analysis of randomized controlled trials.J Am Heart Assoc. 2016;5(7). doi:10.1161/JAHA.115.002713Javadi 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. doi:10.1080/07315724.2016.1140093Anand David AV, Arulmoli R, Parasuraman S.Overviews of biological importance of quercetin: A bioactive flavonoid.Pharmacogn Rev. 2016;10(20):84-89. doi:10.4103/0973-7847.194044Mohos V, Fliszár-Nyúl E, Ungvári O, et al.Inhibitory effects of quercetin and its main methyl, sulfate, and glucuronic acid conjugates on cytochrome P450 enzymes, and on OATP, BCRP and MRP2 transporters.Nutrients. 2020;12(8):2306. doi:10.3390/nu12082306Memorial Sloan Kettering Cancer Center.Quercetin.
MedlinePlus.Quercetin.
National Institute of Health - Office of Dietary Supplements.Dietary supplements for exercise and athletic performance: Fact sheet for health professionals.
Serban MC, Sahebkar A, Zanchetti A, et al.Effects of quercetin on blood pressure: A systematic review and meta-analysis of randomized controlled trials.J Am Heart Assoc. 2016;5(7). doi:10.1161/JAHA.115.002713
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. doi:10.1080/07315724.2016.1140093
Anand David AV, Arulmoli R, Parasuraman S.Overviews of biological importance of quercetin: A bioactive flavonoid.Pharmacogn Rev. 2016;10(20):84-89. doi:10.4103/0973-7847.194044
Mohos V, Fliszár-Nyúl E, Ungvári O, et al.Inhibitory effects of quercetin and its main methyl, sulfate, and glucuronic acid conjugates on cytochrome P450 enzymes, and on OATP, BCRP and MRP2 transporters.Nutrients. 2020;12(8):2306. doi:10.3390/nu12082306
Memorial Sloan Kettering Cancer Center.Quercetin.
Papakyriakopoulou P, Velidakis N, Khattab E, Valsami G, Korakianitis I, Kadoglou NP.Potential pharmaceutical applications of quercetin in cardiovascular diseases.Pharmaceuticals. 2022;15(8):1019. doi:10.3390/ph15081019Zhang M, Swarts SG, Yin L, et al.Antioxidant properties of quercetin. In: LaManna JC, Puchowicz MA, Xu K, Harrison DK, Bruley DF, eds.Oxygen Transport to Tissue XXXII. Vol 701. Springer US; 2011:283-289. doi:10.1007/978-1-4419-7756-4_38
Papakyriakopoulou P, Velidakis N, Khattab E, Valsami G, Korakianitis I, Kadoglou NP.Potential pharmaceutical applications of quercetin in cardiovascular diseases.Pharmaceuticals. 2022;15(8):1019. doi:10.3390/ph15081019
Zhang M, Swarts SG, Yin L, et al.Antioxidant properties of quercetin. In: LaManna JC, Puchowicz MA, Xu K, Harrison DK, Bruley DF, eds.Oxygen Transport to Tissue XXXII. Vol 701. Springer US; 2011:283-289. doi:10.1007/978-1-4419-7756-4_38
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