Vitamin C, a powerful antioxidant, is a water-soluble vitamin which is necessary to form collagen in bones, cartilage, muscle and blood vessels. It also aids in the absorption of iron. We use only USP quality (99.5% or higher purity) Vitamin C. pH = 2.3. For those who would like to supplement their diet with additional Vitamin C without increasing stomach acidity, we have combined fully reacted, low-acidity Potassium/Magnesium Ascorbate with Lemon Bioflavonoids including Hesperidin and Rutin in our buffered formulas. pH = 6.0. Excellent for both children and adults.*