Calcitonin is a peptide hormone with a long history in endocrinology, used in its synthetic, salmon-derived form to treat bone and calcium-related conditions for more than four decades. Its story also includes a notable example of the FDA responding to an emerging safety signal without fully withdrawing a drug's approved use.
What It Is
Calcitonin is a naturally occurring peptide hormone, produced in humans by the thyroid gland's C-cells, that helps regulate calcium and bone metabolism, generally working in opposition to parathyroid hormone. The FDA-approved drug form uses calcitonin derived from salmon, which is structurally similar to the human version but notably more potent at the human calcitonin receptor: calcitonin salmon, sold under names including Miacalcin and Fortical.
FDA-Approved Uses
Calcitonin salmon is FDA-approved for three main indications: Paget's disease of bone, a condition of abnormal bone remodeling; hypercalcemia (dangerously high blood calcium levels) that hasn't responded adequately to other treatment; and postmenopausal osteoporosis in women more than five years past menopause, specifically as a second-line option when other therapies aren't suitable. It's available as both an injectable and a nasal spray formulation.
How It Works
Calcitonin inhibits osteoclasts, the cells responsible for breaking down bone tissue, which slows bone resorption and can help lower blood calcium levels. In Paget's disease, this translates to reduced bone turnover and symptom relief; in osteoporosis, the effect on bone density is generally considered more modest than that of other FDA-approved bone-building or antiresorptive options, discussed in this site's guides to teriparatide and abaloparatide.
The Cancer Signal That Narrowed Its Role
In 2013, after a pooled analysis found a higher rate of cancer diagnoses among patients using calcitonin salmon nasal spray compared with placebo, roughly 2.4 percentage points higher in the data reviewed by European regulators, an FDA advisory committee voted 12-9 that the evidence no longer supported continued marketing of calcitonin salmon nasal spray specifically for osteoporosis. The FDA did not go on to withdraw the osteoporosis indication nationally, a more conservative path than some European regulators took with the nasal spray formulation, but the review prompted updated safety labeling and reinforced that calcitonin is now generally reserved for patients who haven't responded to, or can't use, other osteoporosis therapies. That episode is a concrete, well-documented example of the kind of post-marketing safety signal this site's guide to FAERS and post-market surveillance describes in general terms.
Current Status
Calcitonin salmon remains FDA-approved for its labeled indications today. Because other, generally more effective options exist for osteoporosis specifically, it's now used mainly for Paget's disease, for hypercalcemia, and for the subset of osteoporosis patients who can't use other therapies, rather than as a mainstream frontline bone drug. Clinical guidelines and insurance coverage now generally favor other FDA-approved osteoporosis treatments as first-line options, which is a practical reason calcitonin has become a less visible choice even though it remains fully approved.
The Bottom Line
Calcitonin remains a legitimate, FDA-approved peptide hormone therapy for specific, defined conditions, but its role narrowed considerably after post-approval data raised a safety question the agency took seriously enough to act on. Anyone currently prescribed calcitonin, or considering it, should discuss the specific indication and the available alternatives with their physician.