The invention concerns the application of inorganic polyphosphates (polyP) and complexes of polyP and calcium [polyP (Ca2+ complex)] for prophylaxis and treatment of osteoporosis and other bone diseases by inducing hydroxyapatite formation and decreasing osteoclastogenesis. PolyP and polyP (Ca2+ complex) can be used both as a drug or food supplement and as a material to be injected into bone tissue.