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Quercetin
A powerful bioflavonoid with strong antioxidant, anti-inflammatory, and senolytic properties in the brain - protects against neurodegeneration, reduces neuroinflammation, and supports cerebral blood flow.
Benefits
What is Quercetin?
Quercetin is one of the most abundant and well-studied flavonoids in the human diet, found in high concentrations in onions, apples, berries, capers, and green tea. It is a potent antioxidant, anti-inflammatory, and emerging senolytic compound with extensive research supporting its neuroprotective properties. Quercetin and its metabolites cross the blood-brain barrier and accumulate in brain tissue at functionally relevant concentrations.
A 2020 systematic review published in Biomolecules analysed 28 preclinical studies and concluded that quercetin consistently demonstrated neuroprotective effects through multiple mechanisms: Nrf2 activation, NF-kB inhibition, mitochondrial protection, and direct scavenging of reactive oxygen species. A 2019 study in Nature Medicine by Kirkland and colleagues showed that the combination of quercetin with dasatinib was a potent senolytic cocktail, clearing senescent cells and improving physical function in aged mice. In the brain specifically, a 2021 study in Aging Cell showed that quercetin reduced amyloid-beta plaque load, tau phosphorylation, and cognitive decline in Alzheimer's mouse models. Quercetin also inhibits MAO-A (the enzyme that breaks down serotonin and norepinephrine), contributing to its mood-supporting effects. While primarily studied in animal models and in vitro, the breadth of evidence supporting quercetin's neuroprotective mechanisms is compelling.
- Nrf2 activation: Activates the Nrf2 antioxidant pathway, upregulating endogenous antioxidant enzymes (glutathione, SOD, catalase) to protect neurons from oxidative stress
- NF-kB inhibition: Suppresses NF-kB-mediated inflammatory signalling, reducing neuroinflammation and microglial overactivation
- Senolytic activity: Particularly when combined with dasatinib, clears senescent cells that accumulate in the ageing brain and secrete pro-inflammatory factors
- MAO-A inhibition: Inhibits monoamine oxidase A, slowing the breakdown of serotonin and norepinephrine and supporting mood
- Mitochondrial protection: Protects mitochondrial membrane integrity and function, preserving neuronal energy production
- Anti-amyloid: Reduces amyloid-beta aggregation and promotes clearance through enhanced autophagy and reduced oxidative stress
- Standard dosage: 500-1,000 mg per day, typically divided into two doses
- Bioavailability: Quercetin has low oral bioavailability (approximately 2%). Phytosome and liposomal formulations significantly improve absorption
- Enhanced absorption: Taking with fat, vitamin C, or bromelain improves bioavailability. Quercetin phytosome (Quercefit) may increase absorption up to 20-fold
- Timing: Take with meals for better absorption. Divide into morning and evening doses
- Onset: Antioxidant effects occur acutely. Anti-inflammatory and neuroprotective benefits build over weeks of consistent supplementation
- Generally safe: Quercetin is a natural dietary component with extensive history of safe consumption in foods
- High-dose caution: Doses above 1,000 mg/day may cause headache, tingling, or mild kidney stress in susceptible individuals
- Drug interactions: Inhibits CYP3A4 and CYP2C8 enzymes. May increase blood levels of certain medications including cyclosporine, some statins, and calcium channel blockers. Consult your doctor if on medications
- Thyroid: High-dose quercetin may inhibit thyroid peroxidase. Individuals with hypothyroidism should monitor thyroid function
- Anticoagulant interaction: Quercetin may enhance the effects of blood-thinning medications. Use with caution and medical supervision
Natural Sources & Forms
- Quercetin capsules: Standard quercetin dihydrate or anhydrous forms, widely available in 250-500 mg capsules
- Quercetin phytosome: Lipid-bound formulation (e.g. Quercefit by Indena) with dramatically improved bioavailability
- Liposomal quercetin: Liposomal encapsulation for enhanced absorption
- Food sources: Capers (richest source), red onions, apples (with skin), berries, green tea, dark cherries, and buckwheat
Frequently Asked Questions
A powerful bioflavonoid with strong antioxidant, anti-inflammatory, and senolytic properties in the brain - protects against neurodegeneration, reduces neuroinflammation, and supports cerebral blood flow.
The key benefits of Quercetin include: Cognitive Enhancement, Energy, Longevity, Memory, Mood, Stress Relief.
Nrf2 activation: Activates the Nrf2 antioxidant pathway, upregulating endogenous antioxidant enzymes (glutathione, SOD, catalase) to protect neurons from oxidative stress NF-kB inhibition: Suppresses NF-kB-mediated inflammatory signalling, reducing neuroinflammation and microglial overactivation Senolytic activity: Particularly when combined with dasatinib, clears senescent cells that accumulate in the ageing brain and secrete pro-inflammatory factors MAO-A inhibition: Inhibits monoamine oxidase A, slowing the breakdown of serotonin and norepinephrine and supporting mood Mitochondrial protection: Protects mitochondrial membrane integrity and function, preserving neuronal energy production Anti-amyloid: Reduces amyloid-beta aggregation and promotes clearance through enhanced autophagy and reduced oxidative stress
Standard dosage: 500-1,000 mg per day, typically divided into two doses Bioavailability: Quercetin has low oral bioavailability (approximately 2%). Phytosome and liposomal formulations significantly improve absorption Enhanced absorption: Taking with fat, vitamin C, or bromelain improves bioavailability. Quercetin phytosome (Quercefit) may increase absorption up to 20-fold Timing: Take with meals for better absorption. Divide into morning and evening doses Onset: Antioxidant effects occur acutely. Anti-inflammatory and neuroprotective benefits build over weeks of consistent supplementation
Generally safe: Quercetin is a natural dietary component with extensive history of safe consumption in foods High-dose caution: Doses above 1,000 mg/day may cause headache, tingling, or mild kidney stress in susceptible individuals Drug interactions: Inhibits CYP3A4 and CYP2C8 enzymes. May increase blood levels of certain medications including cyclosporine, some statins, and calcium channel blockers. Consult your doctor if on medications Thyroid: High-dose quercetin may inhibit thyroid peroxidase. Individuals with hypothyroidism should monitor thyroid function Anticoagulant interaction: Quercetin may enhance the effects of blood-thinning medications. Use with caution and medical supervision
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