Calcitonin (Salmon)

Various (Miacalcin/Fortical)

Calcitonin is a 32-amino-acid hormone normally produced by the C-cells of the thyroid gland, where it helps regulate calcium balance by opposing the actions of parathyroid hormone. The salmon form is used medically because it is substantially more potent and longer-acting at the human calcitonin receptor than the native human peptide. Synthetic salmon calcitonin is an approved drug, available historically as a nasal spray (Fortical, Miacalcin) and as an injection. Mechanistically, calcitonin is antiresorptive: it directly inhibits osteoclasts, the cells that dissolve bone, which both slows bone loss and lowers elevated blood calcium. This gives it three classic roles — Paget's disease of bone, hypercalcemia of malignancy (as a rapid but short-lived adjunct), and postmenopausal osteoporosis. It also has a modest, well-documented analgesic effect on the acute pain of vertebral compression fractures, which is one reason it is sometimes used short-term after such fractures. Calcitonin's place in osteoporosis has narrowed considerably over time. It is a weaker antiresorptive than bisphosphonates or denosumab, and long-term nasal use has been associated with a small possible increase in cancer risk in pooled analyses, prompting regulators to recommend it only when other treatments are unsuitable and generally for shorter durations. It remains a genuinely approved medicine used under medical supervision, and this entry is educational reference material rather than guidance to self-source it.