Healthy, resilient bones are made of:2/3 Calcium for Bone strength1/3 Collagen for Flexibility Caltrate Minis Plus Minerals provides Calcium & Vitamin D3, plus extra minerals to stimulate collagen production for stronger more flexible bones. MinisYour bones are awesome! They are actually 1/3 collagen to flex under pressure. That's what helps make them so strong. But over time, they need help staying healthy. That's why Caltrate Minis Plus Mineral is the only small size calcium supplement that is formulated with the calcium and Vitamin D3 you need for bone strength, plus magnesium and other essential minerals that stimulate collagen production for healthy, flexible bones.