AlphaSorb-C 500 mg, Buffered Bioavailable Vitamin C, 180 Vcaps, NOW FoodsNOW AlphaSorb C 500 Antioxidant Protection. Threonic Acid & Alpha Lipoic Acid Enhanced. Buffered, Bioavailable Vitamin C. Vegetarian Formula. NOW AlphaSorb CT contains the Vitamin C metabolite, Threonic Acid, which has been shown to enhance cellular uptake of Vitamin C. This buffered, non acidic Vitamin C supplement also contains Alpha Lipoic Acid, an antioxidant known to help regenerate Vitamin C in the body. Furthermore, studies suggest that Alpha