Quercetin
TL;DR
Flavonoid found in onions, apples, and capers
Moderate evidence for heart health (blood pressure) and allergy relief
Low evidence for metabolic and cognitive health
Acts as a 'zinc ionophore,' helping zinc get into cells
Safe and well-tolerated
Cost: ~$10-20/month
Best for: High blood pressure, seasonal allergies, immune support
What it is
Quercetin is one of the most abundant antioxidants in the human diet. It is a 'senolytic' agent, meaning it helps the body clear out 'zombie' cells that have stopped dividing but are still causing inflammation.
It is widely used for two main reasons: its ability to stabilize mast cells (reducing histamine for allergy relief) and its role as a zinc ionophore, which makes it a popular immune-support supplement during cold and flu season.
What the research says
Quercetin is a proven blood pressure lowerer. Hypertension. A meta-analysis of 7 RCTs found that 500mg of quercetin daily significantly reduced both systolic and diastolic blood pressure in hypertensive patients. Cholesterol. It may also modestly reduce LDL cholesterol by inhibiting its oxidation.
While it shows some benefit for blood sugar in animal studies, human results are modest. It may help reduce 'metabolic inflammation,' but it shouldn't be relied upon as a primary glucose-lowering tool.
The evidence is mostly neuroprotective in theory. Brain Health. By reducing oxidative stress and clearing out senescent cells, quercetin is a logical brain-aging supplement. However, clinical trials in cognitive decline are still too few to make a recommendation.
Quercetin on Amazon
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Safety
Very safe. Doses up to 1,000 mg are well-tolerated. Very high doses may theoretically affect kidney function, though this is rare.
Interactions
- Antibiotics: May interfere with the action of Quinolone antibiotics.
- Statins: May increase the blood levels of certain statins.
- Blood Thinners: May have mild anti-platelet effects.
Dosing
Standard Dose: 500-1,000 mg daily. Form: Quercetin Dihydrate is standard. Tip: For allergies, take it for 2 weeks before the season starts. For general health, it pairs perfectly with Zinc.
Cost
Affordable. $10-20 per month.
The bottom line
Quercetin is a versatile flavonoid. If you have high blood pressure or allergies, it's a great 'foundational' addition to your supplement routine.
Sources for this page include published meta-analyses, systematic reviews, and NIH dietary supplement fact sheets. All claims reflect the evidence as of early 2026.
This is not medical advice. Consult your healthcare provider before starting any supplement, especially if you take medications.