Scientists and health organizations around the world now recommend daily consumption of 1000 IU (or 25 mcg) of vitamin D to support many aspects of health, including bone and heart health. And the form most recommended for its superior bioavailability is vitamin D3 (cholecalciferol). Nature\'s Plus is pleased to offer products providing 1000 IU of vitamin D3. Vitamin D3 1000 IU / Vitamin K2 100 mcg employs the most bioavailable, effective nutrient forms of these essential bone nutrients, for optimal absorption and utilization: vitamin D3 (cholecalciferol) and vitamin K2 (menatetrenone). The vitamin D3 in all Nature\'s Plus products conforms to the strictest standards for purity.