Romosozumab arose from a genetic discovery that revealed the body’s own natural ability to increase bone strength. It is a treatment which aims to block the activity of the protein sclerostin. This diminishes bone breakdown and removal and stimulates bone formation, thereby increasing bone strength. The effectiveness and safety of romosozumab in women with postmenopausal osteoporosis has been evaluated in phase II and phase III clinical trials. Two of the three phase III studies have been completed (STRUCTURE and FRAME) and one is still currently ongoing (ARCH). The results of these studies demonstrates that romosozumab works quickly within 12 months to form new bone and lower the risk of a fracture, providing a new treatment strategy for patients with osteoporosis to quickly build bone strength before transitioning to anti-resorptive treatment to maintain the gains.