Bioavailable Calcium Source NOW® Calcium Hydroxyapatite is naturally processed from Australian, certified BSE-free, young pasture-fed cattle. It is a highly absorbable source of microcrystalline hydroxyapatite (MCHA), which includes calcium, phosphorus, magnesium, protein, minerals and amino acids normally found in bone tissue.* Calcium and phosphorus are essential for healthy bone formation; however, additional minerals and amino acids are also important.* NOW® Calcium Hydroxyapatite provides a bioavailable source of dietary calcium together with other nutrients that assist in the maintenance of healthy bone structure and function.* Natural color variation may occur in this product.