Sclerostin is a secreted protein from osteocytes that inhibits Wnt signaling. Wnt signalling plays important roles in osteoblastic differentiation hence bone formation. Therefore, inhibition of sclerostin promotes bone formation. A monoclonal antibody has been generated against sclerostin, which has been shown to stimulate bone formation and increase bone volume in rodents and primates. Preliminary data on human showed this antibody increases markers for bone formation. Clinical phase 2 study using this antibody in postmenopausal osteoporosis was initiated in 2009, of which results are anticipated.