Quercetin
Nature's antihistamine. Quercetin is a flavonoid found in onions, apples, berries, and many other plants. It's famous for stabilizing mast cells (reducing histamine release), but it's also a powerful antioxidant, anti-inflammatory, antiviral compound, and emerging senolytic (eliminates senescent cells). One of the most versatile plant compounds.
Key Functions
Mast Cell Stabilization
Prevents mast cells from releasing histamine. Natural antihistamine effect. Helps allergies.
Antioxidant
Powerful free radical scavenger. Protects cells from oxidative damage. Regenerates vitamin C.
Anti-Inflammatory
Inhibits NF-κB pathway. Reduces inflammatory cytokines. Helps inflammatory conditions.
Zinc Ionophore
Helps zinc enter cells. Zinc + quercetin combo for immune support. Antiviral mechanism.
Antiviral
Inhibits viral replication. Studied for respiratory viruses. Works with zinc.
Senolytic
Clears senescent "zombie" cells. Combined with dasatinib in research. Longevity interest.
Common Uses
Allergies & Histamine
- Seasonal allergies: Start before pollen season
- Histamine intolerance: Reduces reactions
- Asthma: May help inflammation
- Hives/urticaria: Mast cell calming
Immune & Longevity
- Viral illness: With zinc for colds
- Inflammation: Chronic inflammatory conditions
- Anti-aging: Senolytic protocols
- Exercise recovery: Reduces oxidative stress
Food Sources
Onions
Highest source. Red onions have more. Outer layers richest. Don't peel too much.
Apples
Especially the skin. "Apple a day" partly from quercetin.
Berries
Blueberries, blackberries, elderberries. Elderberry particularly studied.
Capers
Surprisingly high. Add to Mediterranean dishes.
Green Tea
Contains quercetin along with other catechins.
Buckwheat
Pseudograin with good quercetin content. Gluten-free.
Supplementation
Dosing
Typical: 500-1000mg daily. For allergies, start 2-4 weeks before season. Can divide doses.
Forms
Quercetin dihydrate, quercetin phytosome (better absorbed). With bromelain enhances absorption.
Combinations
With zinc for immune support. With vitamin C synergy. With bromelain for absorption.
Timing
Take with food for better absorption. For allergies, best as preventive before exposure.