Quercetin
Quercetin Dihydrate
Powerful flavonoid antioxidant found in many foods, studied for immune support, inflammation, and emerging longevity benefits.
Quercetin is one of the most abundant flavonoids in the diet, found in onions, apples, berries, and tea. It has potent antioxidant and anti-inflammatory properties. Research shows benefits for immune function, allergies, and exercise performance. Recently gained interest as a potential senolytic (clearing damaged cells) for longevity.
Mechanisms of Action
Antioxidant Activity
Neutralizes free radicals and supports other antioxidants
Anti-Inflammatory
Reduces inflammatory signaling
Senolytic Effects
May help clear damaged senescent cells
Recommended Dose
500-1000mg
Optimal Timing
- With meals containing fat
- Split into 2 doses
Take with food
Best Form
Quercetin phytosome (improved absorption)
Alternatives: Quercetin dihydrate, Quercetin + bromelain, Liposomal
Standard quercetin has poor absorption. Phytosome forms or combining with bromelain may improve bioavailability.
Duration
Minimum: 4 weeks
Optimal: 8 weeks
Cycling: Not required
Note: Bioavailability is low; taking with fat and vitamin C may help. Some prefer phytosome or liposomal forms for better absorption.
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Immune Support
Enhanced immune function and reduced illness
Allergy Relief
May reduce histamine and allergy symptoms
Reduced Inflammation
Lower inflammatory markers
Dietary amounts safe; supplements not well-studied
Avoid high doses; may affect kidney function
Who Should NOT Take This
- Kidney disease (high doses)
- Before surgery
Drug Interactions
May compete for absorption
May have mild antiplatelet effects — may affect platelet aggregation or vitamin K-dependent clotting factors, altering anticoagulant efficacy
May inhibit drug metabolism
Possible Side Effects
Tip: Take with food; reduce dose
Tip: Take with meals
Tip: Reduce dose
Warnings
- Low bioavailability — consider enhanced absorption forms
- Very high doses may affect kidney function
- May interfere with certain antibiotics
Vitamin C
enhancesQuercetin regenerates vitamin C; vitamin C improves quercetin absorption
Mutual enhancement of antioxidant effects
Resveratrol
enhancesQuercetin may improve resveratrol bioavailability
Enhanced longevity and antioxidant effects
Zinc
complementaryQuercetin is a zinc ionophore, improving zinc uptake
Enhanced immune support, especially for viral infections
Bromelain
enhancesBromelain enhances quercetin absorption
Enhanced anti-inflammatory and anti-allergy effects
Fisetin
complementaryBoth are senolytics with different selectivity
Broader senolytic coverage
Luteolin
complementaryBoth flavonoids with anti-inflammatory effects
Enhanced anti-inflammatory and antihistamine effects
Top studies from 40+ peer-reviewed papers
Okselni T et al. • Naunyn-Schmiedeberg's archives of pharmacology (2025)
“The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.”
Key Findings:
- Furthermore, quercetin significantly inhibited tyrosinase activity (Z-score, 1.95), resulting in a significantly reduced melanin content (Z-score, 2.56).
- A significant reduction in DNA damage (Z-score, 3.27), melanoma cell viability (Z-score, 2.97), and tumor formation was also observed to ensure the promising activity of quercetin for skin issues.
- This review highlights quercetin's potential as a multifaceted agent in skin care and treatment.© 2024.
- The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
Liang H et al. • Renal failure (2025)
“Through rigorous experimental validation, our study demonstrates AS's significant clinical efficacy in managing DN.”
Key Findings:
- Meanwhile, when the treatment duration exceeds 12 weeks, AS demonstrated a significant reduction in fasting blood glucose levels, indicating a time-dependent effect.
- Through rigorous experimental validation, our study demonstrates AS's significant clinical efficacy in managing DN.
- Specifically, AS has been shown to enhance renal function, ameliorate renal fibrosis, and positively influence iron metabolism.
- Despite these promising outcomes, future research with a larger sample size must be conducted to further substantiate these findings.
Wu D et al. • Frontiers in immunology (2025)
“This systematic review confirms that the efficacy of dietary polyphenols is significantly composition-specific.”
Key Findings:
- This systematic review confirms that the efficacy of dietary polyphenols is significantly composition-specific.
- Curcumin and salidroside can improve the course of COPD by regulating blood pressure, inflammation, and the coagulation pathway, supporting the hypothesis of "polyphenol targeting of metabolic-inflammatory networks".
- However, the possible negative effects of anthocyanins warn against ingredient heterogeneity.
- Clinical significance: Curcumin (200-500 mg/day) and tanshinone are recommended as adjuvant treatment options for COPD, but blind combination should be avoided; the safety of ingredients such as quercetin needs to be further verified.
Zhou P et al. • PloS one (2024)
“The rankings of safety and efficacy of the 12 antioxidants vary.”
Key Findings:
- The rankings of safety and efficacy of the 12 antioxidants vary.
- Due to the low methodological quality of the included studies, the probability ranking cannot fully explain the clinical efficacy, and the results need to be interpreted with caution.
- More high-quality studies are still needed to verify our findings.
Zanjirband M et al. • Journal of cellular and molecular medicine (2024)
“Journal of Cellular and Molecular Medicine published by Foundation for Cellular and Molecular Medicine and John Wiley & Sons Ltd.”
Key Findings:
- Polycystic ovary syndrome (PCOS), a major cause of female infertility, affects 4%-20% of reproductive-age women.
- Salusin-β serum levels in individuals with PCOS were identified as a potential biomarker for increased risk of OVCA.
- Gene signature-based drug repositioning identified several drug candidates: metformin, fenofibrate, fatostatin, melatonin, resveratrol and quercetin, some already established and prescribed for PCOS.
- In conclusion, this study provides a strong basis for further research to confirm the identified molecular signatures and associated causal links for potential therapeutic prevention strategies for EC and OVCA in women with PCOS.© 2024 The Author(s).
Study Type Distribution
Goals This Supplement Supports
Related Goals
This information is for educational purposes only and is not intended as medical advice. Always consult a qualified healthcare provider before starting any supplement.