Quercetin
Flavonoid with anti-inflammatory, antihistamine, and immune support properties.
By Suplagen Team · Updated
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.
How much to take
The catalog range is 500 to 1,000 mg daily, and 1,000 mg is the ceiling. The moderate evidence for anti-inflammatory effects sits in that range; immune and allergy support are graded emerging.
Bioavailability is the weak point. Phytosome or liposomal forms improve it significantly, so a lower dose of a better form often beats a bigger dose of plain quercetin.
When and how to take it
With food, once daily. It's often paired with bromelain or vitamin C for absorption, and with zinc, since quercetin acts as a zinc ionophore.
For inflammation, our guide puts it alongside turmeric and black seed oil at the same moderate grade.
Who should skip it
Kidney disease is a caution at high doses. Interactions: cyclosporine (high severity; transplant patients must avoid it), fluoroquinolone antibiotics (moderate), and anticoagulants (mild). Pregnancy safety isn't established.
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.
Common questions
What is the right quercetin dosage?
500 to 1,000 mg daily with food. 1,000 mg is the ceiling, and phytosome or liposomal forms absorb far better than standard powder.
Should I take quercetin with zinc?
It's a deliberate pairing: quercetin helps zinc get into cells. Quercetin and zinc together covers doses and timing.
Is quercetin safe to take daily?
At catalog doses with food, for most people, yes. The exceptions are kidney disease, cyclosporine, fluoroquinolones, and blood thinners, where a doctor decides.