# Calcitonin (salmon) > A calcium-lowering hormone of the thyroid C-cells — the salmon form, far more potent than human, is used for hypercalcemia, Paget’s disease, and bone pain. - Also known as: Salmon calcitonin, Miacalcin, Fortical, sCT - Class: Peptide Hormones - FDA approved: Yes - Canonical page: https://americanpeptide.com/catalog/calcitonin ## Overview Calcitonin is a 32-amino-acid hormone secreted by the thyroid’s parafollicular C-cells that lowers blood calcium — the functional opposite of parathyroid hormone. The therapeutic version is salmon calcitonin, which binds the human receptor far more potently and durably than the human peptide, a quirk of comparative endocrinology that made the fish hormone the drug of choice for hypercalcemia, Paget’s disease of bone, and osteoporosis-related bone pain. Calcitonin sits on the opposite side of calcium balance from parathyroid hormone (teriparatide, elsewhere in this catalog). PTH raises blood calcium; calcitonin lowers it by switching off the osteoclasts that dissolve bone. In normal human physiology calcitonin’s day-to-day role is relatively minor, but pharmacologically it became a useful brake on bone breakdown. The clinically interesting fact is species. Salmon calcitonin binds the human calcitonin receptor with much higher affinity and a longer-lasting effect than human calcitonin, so the marketed drug is the fish sequence, not the human one — a rare case where another species’ hormone is the better human therapeutic. It is available as injection and as a nasal spray (Miacalcin, Fortical). Its therapeutic niche has narrowed as more potent agents (bisphosphonates, denosumab, and the anabolic PTH analogs) took over osteoporosis, and long-term nasal-spray data raised a possible malignancy signal that tightened its labeling. Today calcitonin is mainly used short-term for hypercalcemia, for Paget’s disease, and notably for the acute bone pain of vertebral fracture, where it has a distinctive analgesic effect. It is a good example of an older hormone therapy repositioned around its remaining strengths. ## Mechanism Agonist at the calcitonin receptor (a GPCR) on osteoclasts, inhibiting bone resorption and thereby lowering serum calcium; it also increases renal calcium excretion. The net effect opposes parathyroid hormone in calcium homeostasis. ## Chemistry | Property | Value | | --- | --- | | Molecular weight | 3431.9 Da | | CAS number | 47931-85-1 | ## Sequence ``` CSNLSTCVLGKLSQELHKLQTYPRTNTGSGTP (1–7 disulfide, C-terminal amide; salmon) ``` ## Research areas Studied in: Hypercalcemia, Paget’s disease, Osteoporosis, Calcium regulation, Peptide hormones. Guides on this site: - [Peptide Hormone Synthesis](https://americanpeptide.com/research-areas/peptide-hormones): How hormone sequences are turned into pure, stable, manufacturable synthetic drugs. ## Key research - Hypercalcemia — rapidly lowers elevated serum calcium by inhibiting osteoclastic bone resorption; used as short-term acute therapy. - Paget’s disease of bone — reduces the accelerated bone turnover characteristic of the disease. - Osteoporotic bone pain — has a recognized analgesic effect on acute pain from vertebral compression fractures. - Cross-species potency — salmon calcitonin out-binds the human hormone at the human receptor, which is why the fish sequence is the drug. - PTH counterpoint — physiologically opposes parathyroid hormone in calcium homeostasis. ## Storage, handling & synthesis **Synthesis.** A 32-residue chain with an N-terminal 1–7 disulfide ring and a C-terminal amide — long by solid-phase standards and prone to on-resin aggregation, so it demands careful coupling, pseudoproline/backbone-protection strategy, and a controlled oxidation step to set the disulfide cleanly. Notably the manufacturing target is the salmon sequence, not the human one, because it binds the human receptor far more potently: a case where pharmacology, not species, dictates what you synthesize. Purity is dominated by deletion sequences and disulfide isomers. ## FAQs ### What does calcitonin do? It lowers blood calcium by inhibiting the osteoclasts that break down bone — the functional opposite of parathyroid hormone. As a drug it is used for hypercalcemia, Paget’s disease, and certain bone pain. ### Why is salmon calcitonin used instead of the human hormone? Salmon calcitonin binds the human calcitonin receptor more potently and for longer than human calcitonin, making the fish version the more effective therapeutic. ### Is calcitonin still widely used? Less than it once was. More potent bone agents have taken over much of osteoporosis care, and long-term nasal-spray safety data tightened its labeling, so it is now mostly used short-term for hypercalcemia, Paget’s disease, and acute fracture pain. ### Is this medical advice? No — this is a research and educational reference, not dosing guidance. ## Latest research Recent trials and publications mentioning Calcitonin, pulled automatically from ClinicalTrials.gov and PubMed (unfiltered search results, refreshed daily). ### Recent trials - [Clinical Trials of IBI3040 in Healthy Participants and Overweight or Obese Participants](https://clinicaltrials.gov/study/NCT07765160) — NOT_YET_RECRUITING · PHASE1 · NCT07765160 - [Efficacy of Ultrasound-Guided Combined Greater Occipital Nerve Block and Greater Auricular Nerve Block Versus Greater Occipital Nerve Block Alone in the Management of Chronic Migraine](https://clinicaltrials.gov/study/NCT07763678) — NOT_YET_RECRUITING · PHASE4 · NCT07763678 - [Eary Infusion of Eptinezumab for TreatmEnt of ACute Post-Traumatic Headaches (ELITE-ACT)](https://clinicaltrials.gov/study/NCT07191145) — NOT_YET_RECRUITING · PHASE3 · NCT07191145 - [Pregnancy Registry, Infants, Serum/Milk Analysis (PRISMA)](https://clinicaltrials.gov/study/NCT06940323) — RECRUITING · NCT06940323 - [A Research Study on How Well Semaglutide Helps Children and Teenagers With Excess Body Weight Lose Weight](https://clinicaltrials.gov/study/NCT05726227) — ACTIVE_NOT_RECRUITING · PHASE3 · NCT05726227 - [Auricular Point Acupressure to Manage Chemotherapy Induced Neuropathy](https://clinicaltrials.gov/study/NCT04920097) — COMPLETED · NA · NCT04920097 --- Source: AmericanPeptide.com — https://americanpeptide.com/catalog/calcitonin Data license: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Attribution: AmericanPeptide.com. Research reference only — computational and educational content, not medical advice.