Quercetin is a type of plant pigment belonging to a group called flavonoids, which give fruits, vegetables, and flowers their colors. It’s naturally found in onions, berries, apples, tomatoes, broccoli, asparagus, buckwheat, and red wine. It can also be taken as a supplement. These supplements are available in capsule, pill, or powder form. Quercetin is sometimes packaged with the enzyme bromelain since both
Quercetin Uses and Health Benefits
Quercetin benefits many body processes. Flavonoids like quercetin act as antioxidants, which means they neutralize free radicals, which are particles in the body that can damage DNA and cell membranes. This makes quercetin effective in protection against cancer and heart disease.1 It’s also said to combat hypertension, strengthen capillaries to reduce bruising, and improve circulation.5,6,7 Other quercetin uses
Quercetin Side Effects and Precautions
Quercetin is considered safe, but dosage amounts vary depending on the person and condition being treated. Quercetin side effects can include upset stomach and headache. In high doses, defined as over one gram per day, it can cause kidney damage and loss of protein function. Recommended doses start at 100 to 250 mg three times per day, with up to 400 mg twice daily to combat hay fever. Take quercetin sparingly with breaks between doses. Do not take quercetin supplements if you are pregnant or breastfeeding or have kidney disease.1,2
Quercetin may interact with certain herbs and medications, including antibiotics and anticoagulants.1 It also interacts with enzymes that break down felodipine. Avoid quercetin supplements if you’re taking felodipine. Quercetin can also change estrogen metabolism in human liver cells, which increases estradiol levels and reduces other estrogen levels in the body.3 Talk to your doctor about using a quercetin supplement before attempting to self-medicate.