Quercetin
Antioxidant
Also known as: Quercetin dihydrate, Quercetin phytosome, Quercetin Phytosome® (Quercefit®), Quercefit, Sophora japonica extract
B
Grade B💊 500-1000 mg daily🎯 9 primary uses🔗 3 synergies⚠️ Review warnings
Levels upHeart & Longevity+50 pts
Overview
Quercetin is a flavonoid antioxidant with anti-inflammatory properties; the Phytosome® delivery system uses phospholipids to enhance absorption compared to standard quercetin. Evidence supports potential benefits for allergies, cardiovascular health, and exercise recovery, though human clinical data remains moderate.
Primary Uses
AllergiesInflammationImmune supportSenolyticAntioxidant supportAnti-inflammatory responseAllergy symptom managementCardiovascular healthExercise recovery
Frequently Asked About Quercetin
How much Quercetin should I take?
The typical effective range is 500 mg twice daily with bromelain. Individual needs vary based on age, body weight, diet, and goals — start at the lower end and adjust based on response. Always consult a healthcare provider before starting a new supplement.
When is the best time to take Quercetin?
Divided doses. Consistency matters more than perfect timing — pick a daily anchor (e.g. with breakfast or before bed) and stick with it.
Should I take Quercetin with food?
Yes.
Does Quercetin interact with medications?
Yes — known interactions include Antibiotics - enhances some and Cyclosporine. If you take any prescription medication, talk to your doctor or pharmacist before starting Quercetin.
What does Quercetin pair well with?
Quercetin stacks well with Bromelain, Vitamin C, and Zinc — these combinations either improve absorption or work synergistically toward common goals.
Who should not take Quercetin?
Quercetin should be avoided or used with caution by people with None. Pregnant or breastfeeding women should consult a healthcare provider before use.
What are the side effects of Quercetin?
Most people tolerate Quercetin well. The most commonly reported side effects are Well tolerated. Side effects are usually dose-dependent — lowering the dose often resolves them.
Dosage
Typical range
500-1000 mg daily
Timing
Divided doses
With food
Yes
Dose Tiers
Moderate
500 mg/day
Optimal
500 mg twice daily with bromelain
Therapeutic
1,000 mg twice daily
Upper Limit
No established UL
Duration
Safe long-term
Special Populations
Allergies, inflammation
Research & Studies
Landmark clinical studies on Quercetin. Each title links to a plain-English breakdown — what the study shows, what its limitations are, and how to read around them.
- Quercetin, inflammation and immunity
Reviews mechanisms by which quercetin modulates inflammatory pathways (NF-κB, mast cell stabilization) and immune response — basis for its use in allergy, upper respiratory infections, and exercise-induced inflammation.
- Quercetin reduces illness but not immune perturbations after intensive exerciseNieman DC, Henson DA, Davis JM, et al. · 2007 · Medicine and Science in Sports and ExerciseRCTPubMed ↗
Double-blind RCT (n=40) in cyclists found 3 weeks of 1g/day quercetin reduced upper respiratory tract infection incidence during an intensive training block without altering immune markers.
Browse all curated studies →
Mechanism of Action
- • Mast cell stabilizer
- • Inhibits inflammatory enzymes
- • Senolytic (clears senescent cells)
- • Zinc ionophore
Evidence Quality
Evidence Grade B
Broad anti-inflammatory effects
Safety & Contraindications
Serious Warnings
- • None
Contraindications
- • None
Common Side Effects
- • Well tolerated
Pregnancy & Breastfeeding
Consult healthcare provider
Liver & Kidney Notes
Safe
Interactions
💊 Medications
- • Antibiotics - enhances some
- • Cyclosporine
🧪 Supplements
- • Works with vitamin C, bromelain
🍽️ Food & Alcohol
- • Onions, apples are sources
Stacking & Synergies
Pairs Well With
Avoid Combining With
None
Best Goal Synergies
AllergiesInflammation
Buying Guide
What to Look For
- • Phytosome or with bromelain
Standardization Markers
Quercetin contentForm
Adulteration risk
Low
Practical Notes
- • Low bioavailability - phytosome helps
- • Natural antihistamine
Tags
antioxidantflavonoidantihistaminesenolyticanti-inflammatoryphytosome deliverystandardized extractplant-based
Top Products with Quercetin
Highest-scored catalog products containing Quercetin, ranked by our scoring engine.
Quercetin PhytosomeThorne92
Quercetin ComplexThorne90
Advanced NutrientsThorne88
Pre-Workout EliteThorne88
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Last reviewed: September 2026 by the Formulate Research Team. Sources cited above; methodology and scoring criteria published here.
Cite this page
Formulate Research Team. (2026, September). Quercetin — Evidence-Based Supplement Guide. Formulate Supplement Encyclopedia. https://app.formulate-health.app/learning/supplements/quercetin
Educational content based on published research and our scoring methodology. Not medical advice — consult a qualified healthcare provider before starting, stopping, or changing supplements, especially if you take medications, are pregnant, or have a medical condition.