Lamberts Ester-C, Due to its acidity, vitamin C, also known as ascorbic acid, may cause slight gastric upset in those with very sensitive stomachs. As patient compliance is always an important consideration of ours, we include Ester-C® in our range of vitamin C products as it is non-acidic (a neutral pH like distilled water) and hence gentle on the stomach. Evidence suggests that Ester-C® is also more bioavailable than ordinary vitamin C, producing higher vitamin C levels inside cells and furthermore, it appears to stay in the body for longer as less is excreted in the urine. IngredientsOne tablet of Lamberts Lamberts Ester-C provides: Ester C 650mg Vitamin C 500mg Other IngredientsTableted with: Calcium Carbonate, Tablet Coating (Hydroxypropyl Methylcellulose, Cellulose, Colours: Titanium Dioxide & Iron Oxide), Silicon Dioxide, Stearic Acid, Magnesium Stearate.Directions1 to 3 tablets daily. CautionOver 1000mg of vitamin C may cause mild stomach upset in sensitive individuals.