No other vitamin C gives you what Ester-C does. Every dose offers advanced immune support with 1,000 mg of Ester-C. What’s more, Ester-C is clinically studied to stay in your white blood cells for up to 24 hours. Ester-C Plus Immune Complex offers this combination of benefits: - Ester-C is pH neutral (non-acidic) and gentle on the stomach. - The only vitamin C with 24-hour immune support - Supports upper respiratory health - Ester-C is clinically studied to stay in the white blood cells for up to 24 hours - Provides Vitamin D3, Vitamin A, and Zinc for extra immune support. - Also includes Elderberry and Echinacea. To use: As a dietary supplement for adults, take two daily, preferably with a meal or as directed by a healthcare practitioner.