Calcitonin, human, is a synthetic 32-amino acid peptide hormone that mimics the naturally occurring calcitonin produced by the parafollicular cells of the thyroid gland. It functions by binding to receptors on osteoclasts, inhibiting bone resorption and lowering serum calcium levels. This reagent is primarily used in pharmaceutical and research applications for the treatment of bone disorders. It helps regulate calcium levels in the body by inhibiting bone resorption, making it effective in managing conditions like osteoporosis, Paget's disease, and hypercalcemia. By reducing the activity of osteoclasts, it promotes bone density and strength, particularly in postmenopausal women who are at higher risk of bone loss. Additionally, it is sometimes used to alleviate bone pain associated with these conditions. Calcitonin is administered via injection or nasal spray, depending on the specific medical need.