Calcium provides the building blocks that help keep bones and teeth strong and healthy. It also supports the health of the colon, heart, musculoskeletal and nervous systems. Magnesium helps to regulate calcium transport and stimulates the secretion of calcitonin, a hormone that aids in the influx of calcium into the bone. Magnesium also works with ATP to produce the energy needed for most reactions in the body. It plays an important role in protein formation and healthy muscle function. Vitamin D is required to promote calcium absorption, which helps to maintain healthy bones and teeth. Vitamin D also supports a healthy immune system and the health of various tissues including breast, colon and prostate tissue. It may support muscle strength in older adults. This formulation provides natural Vitamin D3 for daily supplementation. When combined with a healthy diet and physical activity, calcium may reduce the risk of osteoporosis.