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Quercetin Side Effects & Safety

Evidence:Moderate
·

This content is for informational purposes only and does not constitute medical advice. Statements about dietary supplements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease. Individual results may vary — consult your healthcare provider before starting any supplement. Full disclaimer

Safety Profile

Overall safety rating: Generally Safe

Potential Side Effects

  • Generally well-tolerated with an excellent safety profile
  • Mild headache and tingling in extremities at high doses
  • GI discomfort (nausea, bloating) in some individuals
  • May cause kidney toxicity at extremely high doses (animal data only)

Drug & Supplement Interactions

  • Blood thinners — quercetin may inhibit platelet aggregation; monitor with anticoagulants
  • Cyclosporine — quercetin may increase cyclosporine blood levels via CYP3A4 inhibition
  • Fluoroquinolone antibiotics — quercetin may compete for DNA gyrase binding sites
  • Digoxin — quercetin may increase digoxin levels via P-glycoprotein inhibition

Maximum Dose

Do not exceed: 2000mg/day (well-tolerated in studies)

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References

  1. RCTJustice JN, Nambiar AM, Tchkonia T, et al. (2019). Senolytics in idiopathic pulmonary fibrosis: results from a first-in-human, open-label, pilot study. EBioMedicine. DOI PubMed
  2. Meta-analysisSerban MC, Sahebkar A, Zanchetti A, et al. (2016). Effects of quercetin on blood pressure: a systematic review and meta-analysis of randomized controlled trials. Journal of the American Heart Association. DOI PubMed
  3. Meta-analysisMohammadi-Sartang M, Mazloom Z, Sherafatmanesh S, et al. (2017). Effects of supplementation with quercetin on plasma C-reactive protein concentrations: a systematic review and meta-analysis of randomized controlled trials. European Journal of Clinical Nutrition. DOI PubMed
  4. Meta-analysisLiu L, Barber E, Kellow NJ, Williamson G (2025). Improving quercetin bioavailability: A systematic review and meta-analysis of human intervention studies.. Food chemistry. DOI PubMed
  5. Okselni T, Septama AW, Juliadmi D, Dewi RT, et al. (2025). Quercetin as a therapeutic agent for skin problems: a systematic review and meta-analysis on antioxidant effects, oxidative stress, inflammation, wound healing, hyperpigmentation, aging, and skin cancer.. Naunyn-Schmiedeberg's archives of pharmacology. DOI PubMed
  6. Wu X, Xiao X, Su Y, Zhang Y, et al. (2025). Use quercetin for pulmonary fibrosis: a preclinical systematic review and meta-analysis.. Inflammopharmacology. DOI PubMed
  7. Bian X, Ge Z, Chen X, Zhong S, et al. (2025). Protective effects and mechanisms of quercetin in animal models of hyperuricemia: A systematic review and meta-analysis.. Pharmacological research. DOI PubMed
Show 4 more references
  1. Su P, Chen C, Pang L, Wu K, et al. (2024). Effects of quercetin on polycystic ovary syndrome in animal models: a systematic review and meta-analysis.. Reproductive biology and endocrinology : RB&E. DOI PubMed
  2. Cai Y, Zhang X, Qian H, Huang G, et al. (2024). Uncovering the therapeutic efficacy and mechanisms of Quercetin on traumatic brain injury animals: a meta-analysis and network pharmacology analysis.. Metabolic brain disease. DOI PubMed
  3. Laky M, Arslan M, Zhu X, Rausch-Fan X, et al. (2024). Quercetin in the Prevention of Induced Periodontal Disease in Animal Models: A Systematic Review and Meta-Analysis.. Nutrients. DOI PubMed
  4. Yamaura K, Nelson AL, Nishimura H, Rutledge JC, et al. (2023). Therapeutic potential of senolytic agent quercetin in osteoarthritis: A systematic review and meta-analysis of preclinical studies.. Ageing research reviews. DOI PubMed