Vitamin D3 is essential to bone health as it promotes intestinal re-absorption of Calcium and reduces urinary calcium loss. These together help to maintain healthy serum Calcium levels to support bone health. Vitamin D also supports colon health.Vital Nutrients mission is to manufacture superior quality nutraceuticals that exceed both industry and government standards and provide clinically effective results. They provide over 200 science-based and clinically effective products. They have a comprehensive quality assurance program to ensure that purity and potency is consistently met on every product that they manufacture. Vital Nutrients uses independent U.S. ethical laboratories to test all raw materials and finished products. Each raw material is tested, regardless of origin, for purity and potency. All finished products are tested through a real time stability protocol for expiration date validation. They are an FDA Inspected facility that exceeds FDA cGMPs, and a member of the NPA.