Teriparatide

Teriparatide (brand name Forteo) is the first 34 amino acids of human parathyroid hormone, made by recombinant DNA, and was the first drug approved that actually builds new bone rather than just slowing its loss. FDA-approved in 2002 for osteoporosis at high fracture risk, it is given as a once-daily self-injection. It activates the PTH/PTHrP type 1 receptor on bone cells, switching on the adenylate cyclase/protein kinase A pathway. A brief once-daily spike preferentially stimulates osteoblasts, tipping the remodeling balance toward bone formation.