Opti-CAL is a comprehensive Calcium and Collagen Combination Supplement that has been specifically designed to aid in Bone Building Therapy. Opti-CAL contains Calcium, Magnesium, 1 000 IU Vitamin D3 and Vitamin K2 which all act to strengthen the Inorganic Bone Matrix as well as Type 1 Hydrolysed Collagen, which enhances the flexibility of the Organic Bone Matrix.