How can quercetin help you? What the research says - CancerChoices



Quercetin, found in many plant-based foods and available as a supplement, is linked to better body terrainthe internal conditions of your body, including nutritional status, fitness, blood sugar balance, hormone balance, inflammation and more, and especially lower inflammation.

How can quercetin help you? What the research says

We summarize the clinical evidence for each medical benefit here. We begin with our assessment of the strength of evidence within each category, followed by a brief summary of individual studies or reviews of several studies. In assessing the strength of evidence, we consider the study design, number of participants, and the size of the treatment effect (how much outcomes changed with treatment).

To see more details, click the plus sign to the right of any section.

Improving treatment outcomes

Is quercetin linked to improved survival? Is it linked to less cancer growth or metastasis? Does it enhance the anticancer action of other treatments or therapies? We present the evidence.

Leukemia or lymphoma

Weak evidenceone or more case studies, supported by animal evidence OR small treatment effects of limited clinical significance OR studies with no controls OR weak trends of effects (this is the CancerChoices definition; other researchers and studies may define this differently) of stabilized lymphocyte counts among people with chronic lymphocytic leukemia or small lymphocytic lymphoma treated with quercetin

Optimizing your body terrain

Does quercetin promote an environment within your body that is less supportive of cancer development, growth, or spread? We present the evidence.

See Optimizing Your Body Terrain ›

Find medical professionals who specialize in managing body terrain factors: Finding Integrative Oncologists and Other Practitioners ›

We also recommend that you share with your doctor the information here about how quercetin might affect these terrain factors if you have any imbalances.

Body weight

No evidence of an effectoverall, one or more studies did not demonstrate that a treatment or intervention led to an expected outcome; this does not always mean that there is no effect in clinical practice, but that the studies may have been underpowered (too few participants) or poorly designed. Larger, well-designed studies provide more confidence in making assessments. on measures of body weight among overweight or obese people treated with quercetin  in a combined analysis of studies

Bleeding and coagulation imbalance

Weak evidenceone or more case studies, supported by animal evidence OR small treatment effects of limited clinical significance OR studies with no controls OR weak trends of effects (this is the CancerChoices definition; other researchers and studies may define this differently) of less blood clotting among people with advanced cancer at high risk for blood clots treated with  isoquercetin

High blood sugar and insulin resistance

Modest evidencesignificant effects in at least three small but well-designed randomized controlled trials (RCTs), or one or more well-designed, mid-sized clinical studies of reasonably good quality (RCTs or observational studies), or several small studies aggregated into a meta-analysis (this is the CancerChoices definition; other researchers and studies may define this differently) of lower fasting plasma glucose, although no evidence of an effect on HbA1c levels or a marker of insulin resistance, among people with metabolic syndrome and related disorders treated with quercetin

Insufficient evidencepreclinical evidence only OR clinical studies with such poor or unclear methodology that no conclusion can be drawn OR conflicting findings across clinical studies with no preponderance of evidence in one direction; conflicting evidence occurs when studies find conflicting effects (positive effect vs no effect or negative effect) with the same treatment and the same general study population (same cancer type, for example) (this is the CancerChoices definition; other researchers and studies may define this differently) of a lower marker of insulin resistance and no evidence of an effect on fasting blood glucose or insulin among women with polycystic ovary syndrome treated with quercetin

Hormone imbalance

Changes in hormone levels seen in the studies here may not be beneficial in every situation. Your oncology team needs to determine whether any changes would be favorable for your condition.

Preliminary evidencesignificant effects in small or poorly designed clinical studies OR conflicting results in adequate studies but a preponderance of evidence of an effect (this is the CancerChoices definition; other researchers and studies may define this differently) of lower levels of and luteinizing hormone (LH) and higher levels of adiponectin  among women with polycystic ovary syndrome treated with quercetin

Inflammation

Good evidencesignificant effects in one large or several mid-sized and well-designed clinical studies (randomized controlled trials (RCTs) with an appropriate placebo or other strong comparison control or observational studies that control for confounds) (this is the CancerChoices definition; other researchers and studies may define this differently) of some lower markers of inflammation among people with various noncancer health conditions (not limited to cancer) treated with quercetin

Oxidative stress

Preliminary evidence of lower markers of oxidative stressan imbalance between free radicals and antioxidants in your body in which antioxidant levels are lower than normal; this imbalance can cause harmful oxidation reactions in your body chemistry among people treated with quercetin (not specific to cancer)

Quercetin combined with other therapies

Quercetin and (-)-epicatechin: weak evidence of lower fasting plasma glucose and fewer nuclei abnormalities in buccal epithelial cells among adults at risk of metabolic syndrome eating bread enriched with (-)-epicatechin and quercetin

Managing side effects and promoting wellness

Is quercetin linked to fewer or less severe side effects or symptoms? Is it linked to less toxicity from cancer treatment? Does it support your quality of life or promote general well-being? We present the evidence.

Oral symptoms

No evidence of an effectoverall, one or more studies did not demonstrate that a treatment or intervention led to an expected outcome; this does not always mean that there is no effect in clinical practice, but that the studies may have been underpowered (too few participants) or poorly designed. Larger, well-designed studies provide more confidence in making assessments. on oral mucositisinflammation and ulceration of the mucous membranes lining the digestive tract, usually as an adverse effect of chemotherapy and radiotherapy treatment for cancer during high-dose chemotherapy for blood malignancies among people with treated with quercetin

Quercetin combined with other therapies

Preliminary evidencesignificant effects in small or poorly designed clinical studies OR conflicting results in adequate studies but a preponderance of evidence of an effect (this is the CancerChoices definition; other researchers and studies may define this differently) of better (fewer or less severe) urinary incontinence symptoms and lower impact on quality of life among males scheduled to undergo primary intensity-modulated radiotherapy for localized prostate cancer treated with curcumin, quercetin, hyaluronic acid, and chondroitin sulfate

Weak evidenceone or more case studies, supported by animal evidence OR small treatment effects of limited clinical significance OR studies with no controls OR weak trends of effects (this is the CancerChoices definition; other researchers and studies may define this differently)  of better fatigue scores during treatment with sunitinib among people with kidney cancer treated with isoquercetin, vitamin C, and nicotinic acid

 

Symptoms not specific to cancer

Modest evidencesignificant effects in at least three small but well-designed randomized controlled trials (RCTs), or one or more well-designed, mid-sized clinical studies of reasonably good quality (RCTs or observational studies), or several small studies aggregated into a meta-analysis (this is the CancerChoices definition; other researchers and studies may define this differently) of lower blood pressure among people treated with quercetin (not specific to cancer)

Preliminary evidence of less pain and joint stiffness among women with rheumatoid arthritis (not specific to cancer) treated with quercetin

Preliminary evidence of fewer symptoms among men with chronic pelvic pain syndrome treated with quercetin

Preliminary evidence of less severe numbness, jolting pain, and irritation among people with diabetic peripheral neuropathy treated with QR-333

Reducing cancer risk

Is quercetin linked to lower risks of developing cancer or of recurrence? We present the evidence.

Breast cancer

Preliminary evidencesignificant effects in small or poorly designed clinical studies OR conflicting results in adequate studies but a preponderance of evidence of an effect (this is the CancerChoices definition; other researchers and studies may define this differently) of lower incidence of recurrence among people with breast cancer, especially obese people, eating higher levels of foods containing quercetin

Colorectal cancer

Modest evidencesignificant effects in at least three small but well-designed randomized controlled trials (RCTs), or one or more well-designed, mid-sized clinical studies of reasonably good quality (RCTs or observational studies), or several small studies aggregated into a meta-analysis (this is the CancerChoices definition; other researchers and studies may define this differently) of lower risk of proximal colon cancer, but only among people with high fruit intake or Healthy Eating Index scores, among people eating the highest levels of foods with quercetin, including tea

Gastrointestinal cancer

Colorectal cancer is listed separately.

Preliminary evidence of lower risk of stomach cancer (gastric adenocarcinoma) among people eating foods with the highest levels of quercetin, with stronger effects for female smokers

Gynecological cancer

Ovarian cancer is listed separately.

Weak evidenceone or more case studies, supported by animal evidence OR small treatment effects of limited clinical significance OR studies with no controls OR weak trends of effects (this is the CancerChoices definition; other researchers and studies may define this differently) of lower risk of endometrial cancer among people eating the highest amounts of foods with quercetin

Ovarian cancer

No evidence of an effectoverall, one or more studies did not demonstrate that a treatment or intervention led to an expected outcome; this does not always mean that there is no effect in clinical practice, but that the studies may have been underpowered (too few participants) or poorly designed. Larger, well-designed studies provide more confidence in making assessments. on risk of ovarian cancer among women eating foods with higher levels of quercetin in 2 very large studies

Prostate cancer

Preliminary evidence of lower risk of prostate cancer among men with the highest intake of quercetin in foods

No evidence of an effect on prostate specific antigen (PSA) or PSA doubling time among men with elevated PSA levels treated with quercetin in a small study

Quercetin combined with other therapies

Curcumin and quercetin: weak evidence of fewer and smaller polyps among people with familial adenomatous polyposis treated with curcumin and quercetin

Keep reading about quercetin

Author

Nancy Hepp, MS

Lead Researcher
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Ms. Hepp is a researcher and communicator who has been writing and editing educational content on varied health topics for more than 20 years. She serves as lead researcher and writer for CancerChoices and also served as the first program manager. Her graduate work in research and cognitive psychology, her master’s degree in instructional design, and her certificate in web design have all guided her in writing and presenting information for a wide variety of audiences and uses. Nancy’s service as faculty development coordinator in the Department of Family Medicine at Wright State University also provided experience in medical research, plus insights into medical education and medical care from the professional’s perspective.

Nancy Hepp, MS Lead Researcher

Reviewer

Laura Pole, MSN, RN, OCNS

Senior Clinical Consultant
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Laura Pole is senior clinical consultant for CancerChoices. Laura is an oncology clinical nurse specialist who has been providing integrative oncology clinical care, navigation, consultation, and education services for over 40 years. She is the co-creator and co-coordinator of the Integrative Oncology Navigation Training at Smith Center for Healing and the Arts in Washington, DC. Laura also manages the “Media Watch Cancer News That You Can Use” listserv for Smith Center/Commonweal. In her role as a palliative care educator and consultant, Laura has served as statewide Respecting Choices Faculty for the Virginia POST (Physician Orders for Scope of Treatment) Collaborative as well as provided statewide professional education on palliative and end-of-life care for the Virginia Association for Hospices and Palliative Care.

For CancerChoices, Laura curates content and research, networks with clinical and organizational partners, brings awareness and education of integrative oncology at professional and patient conferences and programs, and translates research into information relevant to the patient experience as well as clinical practice.

Laura sees her work with CancerChoices as a perfect alignment of all her passions, knowledge and skills in integrative oncology care. She is honored to serve you.

Laura Pole, MSN, RN, OCNS Senior Clinical Consultant

Last update: May 7, 2024

Last full literature review: January 2023

We are grateful for research assistance from Adriana Rocio Gutierrez Galvis and Ma Victoria Acuña.

CancerChoices provides information about integrativein cancer care, a patient-centered approach combining the best of conventional care, self care, and evidence-informed complementary care in an integrated plan cancer care. We review complementaryin cancer care, complementary care involves the use of therapies intended to enhance or add to standard conventional treatments; examples include supplements, mind-body approaches such as yoga or psychosocialtherapy, and acupuncture therapies and self carelifestyle actions and behaviors that may impact cancer outcomes; examples include eating health-promoting foods, limiting alcohol, increasing physical activity, and managing stress practices to help patients and professionals explore and integrate the best combination of conventionalthe cancer care offered by conventionally trained physicians and most hospitals; examples are chemotherapy, surgery, and radiotherapy and complementary therapies and practices for each person.

Our staff have no financial conflicts of interest to declare. We receive no funds from any manufacturers or retailers gaining financial profit by promoting or discouraging therapies mentioned on this site.

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