Kirkland Signature Calcium Citrate, Magnesium and Zinc, 500 TabletsED. 11 2027 Get the benefits of essential minerals plus vitamin D from Kirkland Signature. Each serving provides 500 mg of calcium, the primary mineral responsible for strong bones. This formula was carefully crafted to include vitamin D to assist with calcium absorption, as well as magnesium and zinc, two minerals involved in bone formation. The benefits of this product go beyond bone health to also support proper muscle contraction, a healthy immune