Douglas Laboratories Dyna-Cal for healthy bone structure support. The majority of calcium in the body is in the skeleton and the majority of magnesium is located in bone. Bone is constantly undergoing change and in the aging process, a gradual loss of bone occurs. Dyna-Cal offers calcium from a calcium complex with vitamin D3 and magnesium complex combined with other nutrients to support bone structure. Adequate levels of calcium and magnesium and related nutrients are important for bone health. Recommended use: Take 4 tablets daily or as directed by a healthcare professional.