If conventional vitamin C supplements don't sit well with your stomach, Buffered Magnesium Ascorbate Vitamin C Powder from Swanson Premium is an excellent alternative. Vitamin C is one of the most important dietary antioxidants for maintaining good health, which is why it is among the most widely supplemented vitamins. But for some people, the vitamin's acidity can lead to stomach discomfort, especially at higher intakes. Our formula features vitamin C that's buffered with magnesium to make it gentler on the digestive system.