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Qu
Antioxidants
Quercetin
Flavonoid with anti-inflammatory, antihistamine, and immune support properties.
What it is
Quercetin is a flavonoid found in onions, apples, and berries. It has broad anti-inflammatory, antioxidant, and mast cell-stabilizing properties.
How it works
Stabilizes mast cells (reduces histamine release); inhibits lipoxygenase and NF-κB; supports zinc ionophore activity.
What the evidence says
Moderate evidence for anti-inflammatory effects; emerging evidence for immune support and allergy symptom reduction.
Safety Notes
- Phytosome or liposomal forms improve bioavailability significantly. Pairs well with vitamin C and zinc.
- Use caution with: kidney disease (caution at high doses).
- cyclosporine: Quercetin inhibits CYP3A4 and may increase cyclosporine levels; avoid.
- fluoroquinolone antibiotics: May compete for DNA gyrase binding; separate dosing.
- anticoagulants: May have mild antiplatelet effects.
Timing With Other Supplements
- Zinc (Elemental): Quercetin acts as a zinc ionophore; may enhance zinc's intracellular effects.