Like native bone, Xcyte consists largely of calcium-deficient hydroxyapatite, which plays an important role in catalyzing bone formation. In addition, its nanocrystalline structure closely mimics native bone structure and is therefore easily recognized by bone cells. This unique formula – hydroxy- apatite (80-95 wt%), α-tricalcium phosphate (<10 wt%), and calcium pyrophosphate (0.1-10 wt%) – provides an optimal physical and chemical environment for bone biology.