Quercetin (and Isoquercetin)

Overview

Quercetin is a flavonoid polyphenol found in many plant foods including onions, capers, apples, and berries. It exhibits strong antioxidant properties, effectively scavenging reactive oxygen species and supporting antioxidant defenses. Quercetin also has anti-inflammatory, anti-neuroinflammatory, and neuroprotective properties, supporting gut barrier integrity and helping suppress inflammatory signaling. It enhances mitochondrial baseline activity and energy production, supporting mitochondrial function. The bioavailability of quercetin is improved when consumed with vitamin C, folate, and other flavonoids, and isoquercetin (the glycosylated form) is more completely absorbed than the aglycone form.

Recipes

1 recipe containing this substance

Turkey Wing Stew

A collagen-rich, glycine-heavy slow-cooked stew made from affordable turkey wings — supporting gut, joint, sleep, and brain health.

Foods

5 foods containing this substance

Apples

Pectin fiber, quercetin, and food matrix effects on insulin response

Capers

Highest quercetin content among common foods

Kale

Leafy green rich in iron, magnesium, zinc, quercetin, and carotenoids

Onions

Inulin prebiotic, quercetin, and glutathione precursors

Soy

Complete plant protein with isoflavones (genistein) and choline

Biological Mechanisms and Implications

Biological Target	Therapeutic Areas	Mechanism of Action
Hormonal Response	ADHD, Anxiety & GAD	Flavonoid support for calcium modulation and insulin sensitivity
Inflammation	ADHD, Alzheimer's Disease, Anxiety & GAD, Bipolar Disorder, Depression & MDD	Anti-inflammatory, anti-neuroinflammatory, and neuroprotective properties; supports gut barrier integrity and TLR4 suppression
Mitochondrial Support	ADHD, Alzheimer's Disease, Anxiety & GAD, Bipolar Disorder, Depression & MDD	Enhances mitochondrial baseline activity and energy production; supports mitochondrial function
Oxidative Stress	ADHD, Alzheimer's Disease, Anxiety & GAD, Bipolar Disorder, Depression & MDD	Effective antioxidant agent that scavenges reactive oxygen species; supports antioxidant defenses
Stress Response	ADHD, Anxiety & GAD, Depression & MDD	—

References

• Quercetin is an effective antioxidant agent that scavenges reactive oxygen species and has antioxidant, anti-inflammatory, anti-neuroinflammatory, and neuroprotective properties Boots, Haenen, and Bast 2008
• Isoquercetin (glycosylated quercetin) is more completely absorbed than quercetin in the aglycone form, and simultaneous ingestion with vitamin C, folate, and additional flavonoids improves bioavailability Y. Li et al. 2016
• Quercetin enhances mitochondrial baseline activity and energy production Davis et al. 2009
• Quercetin bound to a sugar molecule forming quercitrin has anti-inflammatory and anti-oxidative effects that may be augmented by co-ingestion of omega-3 polyunsaturated fatty acids and olive oil Camuesco et al. 2006
• Quercetin, along with EGCG, supports gut barrier integrity, TLR4 suppression, LPS neutralization, and microglial activation dampening