Your Complete Calcium Formula Get the benefits of three essential minerals and Vitamin D3 working together to support bone health.? Learn More about Kirkland Signature Calcium Citrate Click "View More Details" below. Kirkland Signature Calcium Citrate, Magnesium & Zinc is formulated for building a healthy body.? Calcium is essential for strong bones and Vitamin D3 helps the body absorb calcium.? Zinc and Magnesium assist the body with bone formation.?