Our Zinc Lozenges with Vitamin C provides 23 mg of zinc along with 100 mg of vitamin C in each delicious Honey Lemon flavored lozenge. Zinc Lozenges help support immune function.? For additional formula information, view the Supplement Facts panel. All Windmill supplements are manufactured in the United States in an FDA-inspected facility whose GMPs (Good Manufacturing Practices) are independently verified by qualified certification organizations. Free of artificial colors, flavors and preservatives, Windmill is a trusted name that has been providing America with quality supplements for over 40 years.