Quercetin
Flavonol present in onions, apples, capers and tea, studied for cardiovascular markers and allergic rhinitis, and as a senolytic with dasatinib.
- Evidence
- BModerate evidence
- Studied dose
- 250-1000mg
- Safety score
- Verified references
- 1 study
How it is thought to work
Quercetin is reported to inhibit NF-κB activation, stabilise mast cells and mildly inhibit platelets. With the prescription drug dasatinib (D+Q) it shows senolytic activity[1].
Where to buy Quercetin
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| Vendor | Product | Size | Price | Per unit | Buy |
|---|---|---|---|---|---|
| Amazon |  NOW Supplements, Quercetin with Bromelain, 60 Veg Caps | - | On Amazon | - | Check price on Amazon Ad |
| iHerb | Life Extension, Optimized Quercetin, 60 Vegetarian Capsules | - | about $17.00 at iHerb (as of 24 September 2026) | - | Shop Ad |
| iHerb | Nutricost, Quercetin, 120 Capsules (500 mg per Capsule) | - | about $21.95 at iHerb (as of 24 September 2026) | - | Shop Ad |
| iHerb | Gaia Herbs, Quercetin Synergy, 50 Vegan Capsules | - | about $33.44 at iHerb (as of 24 September 2026) | - | Shop Ad |
What the studies found
| Claimed benefit | Grade | Basis |
|---|---|---|
| Cardiovascular markers | B | Multiple meta-analyses. |
| Allergic rhinitis | B | Small RCTs. |
Each benefit is graded on its own; a substance can have strong evidence for one effect and little for another. What the grades mean.
Dose and timing
Doses used in the research on file, taken as 1-2 doses. Not a recommendation.
Safety and interactions
| Recorded side effect | How often | Severity |
|---|---|---|
| Renal stress (very high dose) | rare | moderate |
| Mild blood-thinning | common | mild |
History
Quercetin has long been studied in cardiovascular disease and allergy. Mayo Clinic ran the first human D+Q trial in 2019, in diabetic kidney disease[1].
References
- Dasatinib plus quercetin: senolytic combination in humans with diabetic kidney disease (Hickson). 2019. PubMed 31542391
Reader reviews
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Sign in to reviewQuercetin: quick answers
- How strong is the evidence for Quercetin?
- The overall grade on file is B (moderate). 2 claimed benefits are graded separately in the table above. The entry cites 1 study.
- What dose of Quercetin has been studied?
- The range on file is 250-1000 mg (1-2 doses). It describes doses used in research, not a recommendation.
- What are the side effects of Quercetin?
- Recorded side effects: Renal stress (very high dose) (rare), Mild blood-thinning (common). Safety score 4/5.
Compared with other substances
Show 6Hide
| Comparison | Grade | Class |
|---|---|---|
| Quercetin vs Fisetin | B | Neuroprotective |
| Quercetin vs Curcumin (Turmeric) | B | Neuroprotective |
| Quercetin vs Magnesium L-Threonate | B | Neuroprotective |
| Quercetin vs Melatonin | A | Neuroprotective |
| Quercetin vs NMN | B | Neuroprotective |
| Quercetin vs Omega-3 (DHA/EPA) | A | Neuroprotective |
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