Unique, patented ascorbate complex bound with calcium carbonate. Naturally processed in purified water without the use of alcohol or acetone solvents. This makes Ester-C a more readily available, readily absorbed form of vitamin C. Vitamin C is a powerful antioxidant shown to support collagen synthesis and respiratory and metabolic function; and reduces oxidative stress. Helps protect the tissues of the body and important in the production of connective tissues like tendons and ligaments. Ester-C® has up to 4X more metabolic activity than standard vitamin C (ascorbic acid). Studies indicate Ester-C is absorbed twice as fast as vitamin C, and levels in tissues and blood are evident for 24 hours. Non-acidic and gentler on the stomach. Extended shelf life.