Quercetin (or Quercitin) is a flavanoid found in many foods and vegetables with potent antioxidant properties. Polyphenol with multiple benefits including reducing histamine-mediated inflammatory response, protecting healthy heart function, supporting healthy blood pressure, supporting healthy cortisol production (stress relief), and has even been studied for potential future developments in the lab. The recommended Serving size for this supplement is between 500mg - 2000mg daily. Side effects are uncommon and can include headaches and tingling in arms and legs at high doses.