MCHC with Magnesium & Vitamin D. Cal Apatite with Magnesium provides advanced bioactive support for healthy bone mineralization with microcrystalline hydroxyapatite concentrate (MCHC) - a calcium-rich bone-derived supplement that provides a full spectrum of highly absorbable macro- and trace minerals Type 1 collagen protein the intact portion of bone and bioactive bone growth factors. Cal Apatite with Magnesium features an exclusive freeze-dried MCHC that ensures higher levels of intact bone growth factors than other MCHC formulas. This unique formula provides optimized levels of vitamin D and a blend of three forms of magnesium designed to be bioavailable to achieve a 2:1 calcium to magnesium ratio for comprehensive musculoskeletol support.  . Calcium along with exercise and a healthy diet can play a significant roles in reducing the rate of bone loss or bone thinning and in protecting bone strength. Magnesium also plays an important role in bone health. Over one-half of the total body stores of magnesium are found in bone tissue.