Supplement
Quercetin is a plant pigment found in onions, apples, and tea that works as an antioxidant and may steady mast cells, the immune cells that release histamine. People mostly look at it for allergies, including hay fever, where the evidence is moderate. Beyond that, research is thin: one small study found HDL cholesterol improved, while others found no clear difference in blood pressure or sprint performance.
Sources: PMID 22486135; PMID 20924595
- Updated
- How we grade
- 19 studies cited
- Best evidence
- Grade C
- Conditions studied
- 12
- Outcomes
- 52
- Graded outcomes
- 00211
Evidence by condition
- Strong
- Moderate
- Limited
- Very limited
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| High-density lipoprotein (HDL) Small Improvement | Improves (the measure goes up) | Small effect | 1 study | 400 people | ||
Studies that measured high-density lipoprotein (hdl) | ||||||
| Low-density lipoprotein (LDL) | Improves (the measure goes down) | 400 people | ||||
| Total cholesterol | Improves (the measure goes down) | 400 people | ||||
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Anxiety Symptoms Small Improvement | Improves (the measure goes down) | Small effect | 38 people | |||
| HbA1c | Improves (the measure goes down) | 1 study | 88 people | |||
| Quality of Life | Improves (the measure goes up) | 1 study | 38 people | |||
High Blood Pressure
- Blood Pressure
- Blood glucose
- High-density lipoprotein (HDL): improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Blood Pressure No effect | NoneNo effect | 1 study | 88 people | |||
Studies that measured blood pressure | ||||||
| Blood glucose No effect | NoneNo effect | 41 people | ||||
| High-density lipoprotein (HDL) | Improves (the measure goes up) | 1 study | 41 people | |||
Studies that measured high-density lipoprotein (hdl) | ||||||
| Oxidative Stress Biomarkers | Improves (the measure goes down) | 1 study | 41 people | |||
Studies that measured oxidative stress biomarkers | ||||||
| Fat Oxidation | Improves (the measure goes up) | 6 people | ||||
| Heart Rate | Improves (the measure goes down) | 41 people | ||||
| Low-density lipoprotein (LDL) | Improves (the measure goes down) | 41 people | ||||
| Metabolic Rate | Improves (the measure goes up) | 6 people | ||||
| vLDL-C | Improves (the measure goes down) | 41 people | ||||
| Weight | Improves (the measure goes down) | 41 people | ||||
Metabolic Health
- Anaerobic Capacity
- Exercise-induced Stress Response: improves
- Rating of Perceived Exertion: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Anaerobic Capacity No effect | NoneNo effect | 1 study | 15 people | |||
Studies that measured anaerobic capacity | ||||||
| Exercise-induced Stress Response | Improves (the measure goes down) | 1 study | 8 people | |||
Studies that measured exercise-induced stress response | ||||||
| Rating of Perceived Exertion | Improves (the measure goes up) | 1 study | 15 people | |||
Studies that measured rating of perceived exertion | ||||||
| Interleukin 6 | Improves (the measure goes down) | 15 people | ||||
| Intestinal Permeability | Improves (the measure goes up) | 8 people | ||||
| Uric Acid | Improves (the measure goes down) | 15 people | ||||
Warm Or Hot Weather Exercise Performance
- Anaerobic Capacity
- Exercise-induced Stress Response: improves
- Rating of Perceived Exertion: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Anaerobic Capacity No effect | NoneNo effect | 1 study | 10 people | |||
Studies that measured anaerobic capacity | ||||||
| Exercise-induced Stress Response | Improves (the measure goes down) | 1 study | 8 people | |||
Studies that measured exercise-induced stress response | ||||||
| Rating of Perceived Exertion | Improves (the measure goes up) | 1 study | 10 people | |||
Studies that measured rating of perceived exertion | ||||||
| Hydration (Total Body Water) | Improves (the measure goes up) | 10 people | ||||
| Intestinal Permeability | Improves (the measure goes up) | 8 people | ||||
| Training Volume | Improves (the measure goes up) | 10 people | ||||
Anaerobic Exercise Performance
- Anaerobic Capacity
- Rating of Perceived Exertion: improves
- Interleukin 6: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Anaerobic Capacity No effect | NoneNo effect | 1 study | 15 people | |||
Studies that measured anaerobic capacity | ||||||
| Rating of Perceived Exertion | Improves (the measure goes up) | 1 study | 15 people | |||
Studies that measured rating of perceived exertion | ||||||
| Interleukin 6 | Improves (the measure goes down) | 15 people | ||||
| Uric Acid | Improves (the measure goes down) | 15 people | ||||
Weight Loss & Maintenance
- Blood Pressure
- Fat Oxidation: improves
- Metabolic Rate: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Blood Pressure No effect | NoneNo effect | 1 study | 6 people | |||
Studies that measured blood pressure | ||||||
| Fat Oxidation | Improves (the measure goes up) | 6 people | ||||
| Metabolic Rate | Improves (the measure goes up) | 6 people | ||||
General Athletic Performance
- Anaerobic Capacity
- Rating of Perceived Exertion: improves
- Interleukin 6: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Anaerobic Capacity No effect | NoneNo effect | 1 study | 15 people | |||
Studies that measured anaerobic capacity | ||||||
| Rating of Perceived Exertion | Improves (the measure goes up) | 1 study | 15 people | |||
Studies that measured rating of perceived exertion | ||||||
| Interleukin 6 | Improves (the measure goes down) | 15 people | ||||
| Uric Acid | Improves (the measure goes down) | 15 people | ||||
Warm- or Hot-Weather Exercise Performance
- Anaerobic Capacity
- Exercise-induced Stress Response: changes; see studies
- Rating of Perceived Exertion: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Anaerobic Capacity No effect | NoneNo effect | 1 study | 10 people | |||
Studies that measured anaerobic capacity | ||||||
| Exercise-induced Stress Response | Changes; see studies | 1 study | 8 people | |||
Studies that measured exercise-induced stress response | ||||||
| Rating of Perceived Exertion | Improves (the measure goes up) | 1 study | 10 people | |||
Studies that measured rating of perceived exertion | ||||||
| Hydration (Total Body Water) | Improves (the measure goes up) | 10 people | ||||
| Intestinal Permeability | Improves (the measure goes up) | 8 people | ||||
| Training Volume | Improves (the measure goes up) | 10 people | ||||
Immune Health
- Interleukin 6
- Intestinal Permeability: improves
- Uric Acid: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Interleukin 6 No effect | NoneNo effect | 15 people | ||||
| Intestinal Permeability | Improves (the measure goes up) | 8 people | ||||
| Uric Acid | Improves (the measure goes down) | 15 people |
Sarcoidosis
- Inflammation
- Oxidative Stress Biomarkers: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Inflammation No effect | NoneNo effect | 12 people | ||||
| Oxidative Stress Biomarkers | Improves (the measure goes down) | 1 study | 12 people | |||
Studies that measured oxidative stress biomarkers | ||||||
Sleep Health
- Fatigue Symptoms
- Sleep Quality: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Fatigue Symptoms No effect | NoneNo effect | 58 people | ||||
| Sleep Quality | Improves (the measure goes up) | 1 study | 58 people | |||
Studies that measured sleep quality | ||||||
Key findings
- High-density lipoprotein (HDL)Improves (the measure goes up)
- Anxiety SymptomsImproves (the measure goes down)
- Blood Pressure
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- Grade C
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Studies cited
19 studies from PubMed
- Quercetin and Exercise Performance: A Meta-Analysis
- Quercetin and Blood Pressure: A Meta-Analysis of Randomized Trials
- Quercetin and Upper Respiratory Tract Infections: A Review
- Quercetin and Metabolic Syndrome: A Comprehensive Review
- Quercetin and Cardiovascular Health: A Systematic Review and Meta-Analysis
- Quercetin and Allergic Diseases: A Systematic Review
- Bioavailability and Safety of Quercetin: A Review
- Quercetin and Lipid Profile: A Meta-Analysis
- Quercetin and Inflammation: A Systematic Review
- Quercetin and Antioxidant Activity: Mechanisms and Clinical Evidence
- Quercetin reduces markers of oxidative stress and inflammation in sarcoidosis
- No evidence for a thermic effect of the dietary flavonol quercetin: a pilot study in healthy normal-weight women
- No effect of nutritional adenosine receptor antagonists on exercise performance in the heat
- Thermotolerance and heat acclimation may share a common mechanism in humans
- Effect of quercetin supplementation on repeated-sprint performance, xanthine oxidase activity, and inflammation
- Quercetin in the treatment of dyslipidemia
- Effects of 6 weeks of quercetin supplementation on energy, fatigue, and sleep in ROTC cadets
- The 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.
- Benefits 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.