Calcium Ascorbate (Source Naturals) Each bottle, 8 ounces of vitamin C as calcium ascorbate. A serving of 1/2 a rounded teaspoon (about 2.7 grams) provides 2,150 mg of vitamin C as calcium ascorbate and 245 mg of calcium. This is a non-acidic form of vitamin C and thus will not harm the teeth (as a powdered ascorbic acid might). It also provides a bit of extra calcium. See the information under Super C/C Mineral Ascorbates for more information on the importance and uses of vitamin C.