Quercetin: Practice Points – Patient Counselling. FAQ

Quercetin is a flavonol belonging to a group of polyphenolic substances known as flavonoids or bioflavonoids and is found in many fruits, vegetables and some herbal medicines.

• According to experimental studies, it has antioxidant, anti-inflammatory, antiviral, mast cell stabilisation, neuroprotective, gastroprotective, hepatoprotectiveand possibly cardioprotective actions.

• In practice, it is used for respiratory allergies such as hayfever, as an adjunct in asthma management, preventing diabetic complications such as cataracts and symptom relief in prostatitis; however, large controlled studies are not available to determine its effectiveness.

• Numerous drug interactions are theoretically possible, mainly due to P-glycoprotein and CYP inhibition.

Quercetin is generally well tolerated. Adverse effects may include nausea, dyspnoea, headache and mild tingling of the extremities

Answers to Patients’ Frequently Asked Questions

What will this supplement do for me?

Quercetin has several pharmacological effects and may provide some symptom relief in allergic conditions and prostatitis, and be beneficial in diabetes and cardiovascular disease; however, further research is required to clarify its effectiveness.

When will it start to work?

This will depend on the indication it is being used to treat.

Are there any safety issues?

Although it is generally well tolerated, numerous drug interactions are possible, so seek professional advice if taking other medication.