What are the recommendations for a quercetin (a type of flavonoid) supplement?

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Last updated: May 1, 2025View editorial policy

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From the Guidelines

I strongly recommend quercetin supplements, specifically 200-500 mg/day, for patients with chronic oxidative stress or malabsorption, as supported by the latest guideline from 2022 1. When considering quercetin supplements, it's essential to prioritize products from reputable brands that undergo third-party testing for quality assurance. The addition of bromelain, a pineapple enzyme, may enhance quercetin absorption. Quercetin is a flavonoid with antioxidant and anti-inflammatory properties found naturally in foods like onions, apples, and green tea. Some key points to consider:

  • Start with a lower dose to assess tolerance
  • Consult your healthcare provider before beginning any supplement, especially if you're pregnant, nursing, taking medications, or have existing health conditions
  • Quercetin may interact with certain antibiotics and blood thinners
  • Dietary supplements should complement, not replace, a balanced diet rich in natural quercetin sources
  • Quality varies between manufacturers, so choose a reputable brand The ESPEN micronutrient guideline from 2022 1 provides a strong consensus (92%) for recommending quercetin supplements in specific patient populations. While other studies discuss the benefits of a balanced diet and healthy eating habits 1, the most recent and relevant guideline for quercetin supplementation is from 2022 1.

From the FDA Drug Label

DIRECTIONS: • chew 1 tablet slightly and allow to dissolve in the mouth. • adults take one every 2 to 4 hours until symptoms improve. • take only as needed to maintain your well-being. The FDA drug label does not answer the question.

From the Research

Quercetin Supplement Recommendation

  • There are no specific recommendations for a quercetin supplement in the provided studies, as they focus on the safety, potential health benefits, and effects of quercetin on exercise performance and disease prevention 2, 3, 4, 5, 6.
  • However, the studies suggest that quercetin is generally considered safe for consumption, with rare reports of mild adverse effects 2, 6.
  • The optimal dosage of quercetin is not established, but studies have used doses ranging from 500 mg to 3000 mg per day 4.
  • It is essential to note that the long-term safety of high supplemental quercetin doses (>1000 mg per day) has not been extensively studied 2.
  • Quercetin may interact with certain drugs, altering their bioavailability, and individuals with pre-damaged kidneys or estrogen-dependent cancer should exercise caution when considering quercetin supplementation 2.

Key Considerations

  • Quercetin's bioavailability can be improved by food matrix components or particular delivery forms 3.
  • The source of quercetin, training status of subjects, and exercise protocol performed may contribute to the effectiveness of quercetin as an antioxidant, anti-inflammatory, or ergogenic agent in exercise 4.
  • Further studies are needed to elucidate quercetin's mechanisms of action, optimize its bioavailability, and assess its long-term safety for widespread utilization 5.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Safety Aspects of the Use of Quercetin as a Dietary Supplement.

Molecular nutrition & food research, 2018

Research

Quercetin: potentials in the prevention and therapy of disease.

Current opinion in clinical nutrition and metabolic care, 2008

Research

Quercetin in Sports and Exercise: A review.

International journal of exercise science, 2023

Research

Recent Advances in Potential Health Benefits of Quercetin.

Pharmaceuticals (Basel, Switzerland), 2023

Research

A critical review of the data related to the safety of quercetin and lack of evidence of in vivo toxicity, including lack of genotoxic/carcinogenic properties.

Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association, 2007

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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