If you’re looking for a supplement that can support free radical scavenging, and helps support healthy sinus, respiratory, and immune system function, look no further than quercetin. Quercetin is a plant compound belonging to the family known as flavonoids and is present in numerous fruits, vegetables, and grains. While the average person is thought to consume 10–100 mg of quercetin through food daily, this formula delivers 500 mg per vegetarian capsule to give you maximum quercetin benefits.