Calcitonin
Also known as: Salmon Calcitonin, Miacalcin, Fortical, Thyrocalcitonin
Overview
Calcitonin is a 32-amino acid peptide hormone produced by parafollicular C-cells of the thyroid gland in response to elevated serum calcium. It acts through calcitonin receptors (CTR) on osteoclasts to inhibit bone resorption and on kidneys to promote calcium and phosphate excretion. Salmon calcitonin, which is approximately 40-50 times more potent than human calcitonin at the human receptor due to structural differences, is used clinically for Paget's disease, hypercalcemia, and osteoporosis (intranasal formulation). It also has significant analgesic properties, particularly for pain associated with vertebral fractures.
Mechanism of Action
Calcitonin binds the calcitonin receptor (CTR), a class B GPCR predominantly expressed on osteoclasts. CTR activation via Gs/cAMP/PKA causes rapid inhibition of osteoclastic bone resorption by: disrupting the osteoclast ruffled border (the acid-secreting membrane), reducing lysosomal enzyme release, and inducing osteoclast quiescence. CTR activation also occurs in renal tubules (promoting calcium/phosphate excretion) and CNS (mediating analgesic effects via descending pain modulation pathways). The analgesic mechanism involves central beta-endorphin release and serotonergic pathway activation.
Potential Benefits
- Osteoclast inhibition reducing bone resorption
- Paget's disease of bone treatment
- Hypercalcemia management
- Analgesic effect for vertebral fracture pain (intranasal formulation)
- Osteoporosis treatment (especially when other agents contraindicated)
Dosage Protocols
The following reflects doses used in published research studies. This is not medical advice. Consult a qualified healthcare professional.
| Beginner | 200 IU nasal spray once daily, alternating nostrils |
| Intermediate | 100 IU SC every other day (Paget's disease) |
| Advanced | 100 IU SC daily (hypercalcemia — short-term) |
| Cycle Duration | Short-term preferred; chronic use limited due to cancer signal |
FDA-approved (Miacalcin, Fortical). Calcitonin-salmon synthetic. Black box concerns about long-term malignancy signal — consider alternatives for chronic osteoporosis.
Use our Reconstitution Calculator to determine exact syringe units for your protocol.
Routes of Administration
Intranasal ~3-5%
Osteoporosis indication. Alternate nostrils daily.
Subcutaneous / Intramuscular Injection ~70%
Paget's disease of bone and hypercalcemia indications.
Read our full Routes of Administration Guide for detailed comparison of all delivery methods.
Stacking Protocols
Popular research stacks involving Calcitonin:
Legacy Osteoporosis Sequencing
Largely replaced by bisphosphonates, denosumab, and teriparatide due to better efficacy and safer long-term profile.
Explore our complete Peptide Stacking Guide for more combinations and safety considerations.
Reconstitution
| Storage | Nasal: refrigerate 2-8°C before first use; room temperature up to 35 days after first use. Injection: refrigerate 2-8°C. |
|---|
Protect from freezing.
Need exact syringe measurements?
Amino Acid Sequence
Cys-Ser-Asn-Leu-Ser-Thr-Cys-Val-Leu-Gly-Lys-Leu-Ser-Gln-Glu-Leu-His-Lys-Leu-Gln-Thr-Tyr-Pro-Arg-Thr-Asn-Thr-Gly-Ser-Gly-Thr-Pro-NH2 (salmon calcitonin; disulfide Cys1-Cys7)
Side Effects & Safety
- Nausea and flushing (SC/IM)
- Nasal irritation (intranasal)
- Hypocalcemia at high doses
- Rare: hypersensitivity reactions
- Long-term use associated with increased cancer risk (EMA review warning)
Safety & Contraindications
This information is for educational purposes only. Consult a qualified healthcare provider before using any peptide.
Pregnancy / Lactation
Bleeding Disorders
Active Skin Infection at Injection Site
FDA Safety Information
FDA labeling warns of a possible increased risk of malignancy with long-term nasal spray use; use only when benefits outweigh risks.
Pharmacokinetics
| Half-Life | ~43 minutes (nasal); ~1.2 hours (injection) |
|---|---|
| Storage | Refrigerate at 2-8°C before first use. Nasal spray: room temperature up to 35 days after opening. Do not freeze. |
Synergistic Compounds
The following compounds have been studied alongside Calcitonin for potential complementary or synergistic effects:
Learn More
References & Further Reading
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