Vitamin C (Ascorbic Acid) is an essential water-soluble vitamin that has a wide range of functions in the human body, with its primary function being a excellent antioxidant. Our 100% pure Vitamin C powder is from Ascorbic Acid. STORAGE INSTRUCTIONS Store in a cool and dry place. NOTE! Do not exceed recommended dose. Supplements are not intended to replace a varied diet. Keep out of reach of children. Store in a cool dry place. See best before date on packaging. If you are pregnant, nursing, have a diagnosed illness or are using prescription medication, consult your doctor before using any supplement.