Calcium citrate is the most highly recommended form of calcium. Calcium Citrate Mini-Tablets provide 800 mg of calcium citrate plus 800 IU of vitamin D3 to support the health of your teeth and bones in each daily dose of 4 tablets. Vitamin D also aids in the absorption of calcium. For energy and additional bone support, Calcium Citrate Mini-Tablets adds boron, organic spirulina, and horsetail. With a gentle-on-the-stomach form of calcium, plus vitamin D, boron and green foods like organic spirulina, Calcium Citrate Mini-Tablets are ideal for those with decreased stomach acid production or digestive issues. Can be taken on an empty stomach.