Ester-c is a breakthrough patented vitamin c formula supported with naturally occurring metabolites. Metabolites help enhance the absorption of vitamin c by your white blood cells, an important part of your immune system. Ester-c's unique, chemical-free manufacturing process neutralizes ph, making it non-acidic and gentle on the stomach. In a daily 1000mg dose, ester-c delivers 24 hour immune support. So once a day is all you need. Added citrus bioflavonoids may help your body better absorb.