Flavonoid
Quercetin
A plant flavonoid with antioxidant and anti-inflammatory properties that support overall brain health.
KÖGN Health grades Quercetin as B (Moderate evidence) and rates it 3.7 out of 5.
Last reviewed · June 2026
Primary effects
- Neuroprotection
- Reduced inflammation
- Cognitive support
How it works
Reduces oxidative stress and inflammation, supporting cellular and neurological health.
Overview
Quercetin is widely studied for its antioxidant and anti-inflammatory effects, which play an indirect role in supporting brain health. While it does not provide acute cognitive enhancement, it contributes to long-term neuroprotection. It is often used as part of a broader health optimisation protocol alongside other polyphenols.
The evidence
Quercetin is a dietary flavonoid with strong antioxidant and anti-inflammatory activity and a large preclinical literature suggesting neuroprotection. The honest gap: almost all of the cognition evidence is from cell and animal studies, with very few human trials and poor oral bioavailability limiting how much reaches the brain. Its nootropic reputation runs well ahead of the human data.
How to dose it
Supplements commonly provide 500–1,000 mg/day; absorption is low, so some products pair it with enhancers. Human cognition dose-finding data are lacking.
When to take it
Chronic.
Safety & side effects
Well tolerated by mouth; very high doses have occasionally been linked to headache or kidney effects.
Who should avoid it
Quercetin can inhibit drug-metabolising enzymes and affect levels of some medications, and may add to blood-thinning effects — check with a clinician if you take prescription drugs or anticoagulants. The strongest evidence is preclinical.
References
Related ingredients
Graded entries that target the same cognitive goals.
Categories
Draft — the dose, safety and evidence notes on this entry were prepared from the published literature and are pending editorial and clinical review.
Educational information, not medical advice. The evidence grade is KÖGN’s editorial assessment of published research, not a health claim. Speak to a qualified clinician before changing what you take.