Bone loss preventing and bone regeneration or bone formation promoting pharmaceutical composition comprising muramyl dipeptide

A method of improving or treating a bone disorder in a subject in need thereof by reducing bone loss or promoting bone regeneration or formation, the method comprising administering to the subject a composition consisting of an effective amount of a muramyl-dipeptide or a muramyl-dipeptide derivative selected from the group consisting of N-acetylmuramyl-L-alanine-D-isoglutamine-lysine, 6-O-stearoyl-N-acetylmuramyl-L-alanine-D-isoglutamine, acetylglucosamine-N-acetylmuramyl-L-alanine-D-isoglutamine and acetylglucosamine-N-acetylmuramyl-L-alanine-D-isoglutamine-lysine, or a pharmaceutically acceptable salt thereof, wherein the bone disorder are osteoporosis, bone damage caused by bone metastasis of cancer cells, osteomalacia, rickets, adynamic bone disease, metabolic bone disease, osteolysis, bone deformity, osteoarthritis, deformity correction, dental correction, bone fracture treatment, osteosynthesis, bone regeneration of false joints, bone formation, and bone grafting.