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Quercetin

Antioxidants

Also known as: Quercetin Dihydrate, Quercetin Phytosome

Quercetin is a powerful flavonoid antioxidant found in many fruits and vegetables. It has anti-inflammatory, antihistamine, and antiviral properties, and acts as a zinc ionophore.

Best Timing

Take with food (fat improves absorption). For allergies, take consistently — effects build over days.

Absorption

Standard quercetin has poor bioavailability (<2%). Phytosome, EMIQ, or isoquercetin forms dramatically improve absorption. Bromelain enhances uptake.

Health Goals
🛡️Immunity🧬Longevity❤️Heart
Who Should Take This
AthletesElderly (60+)High-Stress Individuals
  • Potent antioxidant and anti-inflammatory
  • Natural antihistamine — reduces allergy symptoms
  • Acts as a zinc ionophore (helps zinc enter cells)
  • Antiviral properties
  • Supports cardiovascular health
  • May reduce exercise-induced inflammation
  • Senolytic properties (clears senescent cells)
General health500–1,000 mg

Daily

Allergy support500 mg

Twice daily

Start 2 weeks before allergy season

With zinc (immune support)500 mg quercetin + 30 mg zinc

Daily

Phytosome form250–500 mg

Daily

More potent — lower dose needed

  • -Quercetin dihydrate – standard form, poor bioavailability
  • -Quercetin phytosome (Quercefit) – dramatically improved absorption
  • -Isoquercetin – glycoside form, better absorbed than quercetin
  • -EMIQ (enzymatically modified isoquercitrin) – 40x better absorption
Onions (especially red onions)ApplesBerries (blueberries, elderberries)Capers (richest source per weight)Green tea
ZincSynergy

Quercetin is a zinc ionophore — it shuttles zinc into cells, enhancing its antiviral and immune effects.

Vitamin CSynergy

Vitamin C and quercetin synergize for enhanced antioxidant and antihistamine effects.

BromelainSynergy

Bromelain increases quercetin absorption. Often combined in allergy formulas.

CurcuminSynergy

Both are powerful anti-inflammatories through complementary pathways.

Quercetin reduces illness but not immune perturbations after intensive exercise

Nieman DC, Henson DA, et al. - Medicine and Science in Sports and Exercise (2007)

1,000 mg quercetin/day for 5 weeks significantly reduced upper respiratory tract infections in athletes after extreme exercise.