Natural Treasure Esterified C is a more advanced form of vitamin C. It is extracted from natural plants and processed using international patented technology to produce esterified calcium ascorbate, which removes the acidity of ordinary vitamin C and is harmful to the stomach. Mild and non-irritating; it also includes a high-efficiency vitamin C absorption system - complex bioflavonoids and natural vitamin C metabolites, which synergize with each other to enable vitamin C to be released evenly 24 hours a day, promote cell absorption while delaying kidney excretion, significantly Improve the absorption rate and retention rate of vitamin C in the human body. Esterified C is carefully produced by the classic American brand Nature’s bounty, a subsidiary of NBTY, the world’s largest nutritional and dietary supplement group, and is 100% imported from the United States.