NOW Foods AlphaSorb-C 500 mg delivers vitamin C complexed with calcium threonate — a form that reduces ascorbic acid's acidity, making it significantly gentler on the stomach and tooth enamel than plain ascorbic acid. This mineral ascorbate form maintains the full antioxidant and biological activity of vitamin C while eliminating the gastric irritation that high-dose ascorbic acid can cause in sensitive individuals. AlphaSorb-C is ideal for those who want the immune, collagen, and antioxidant benefits of high-dose vitamin C without GI discomfort. Each capsule delivers 500 mg of vitamin C with a neutral pH, making multiple daily doses practical and comfortable. Manufactured in NOW's GMP-certified facility with potency verification.