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approvedBone & Joint

Elcatonin

Also known as: Elcitonin, Carbocalcitonin, AST-120, [Asu1,7]-eel calcitonin

Elcatonin is a synthetic derivative of eel calcitonin approved in Japan for the treatment of osteoporosis and associated bone pain, as well as hypercalcemia and Paget disease of bone. Distinguished by its replacement of the disulfide bridge with an aminosuberic acid residue (creating a more stable molecule), elcatonin has been widely used in Japanese clinical practice since the 1980s. It inhibits osteoclast-mediated bone resorption and provides notable analgesic effects on osteoporotic bone pain through central and peripheral mechanisms.

3 cited references·5 researched benefits

Quick Answer

Elcatonin is a synthetic eel calcitonin derivative approved in Japan for osteoporosis, bone pain, and hypercalcemia. Unlike salmon calcitonin, it uses an aminosuberic acid bridge instead of a disulfide bond, providing superior chemical stability. Administered as a weekly intramuscular injection of 20 units, elcatonin inhibits osteoclast bone resorption and provides analgesic relief for osteoporotic fracture pain. It has been a mainstay of Japanese osteoporosis treatment for over three decades.

Key Facts

Mechanism
Elcatonin binds to calcitonin receptors (CTR) on osteoclasts, a G-protein coupled receptor that activates cAMP and intracellular calcium signaling. This rapidly inhibits osteoclast ruffled border formation, reducing bone resorption within hours. The analgesic mechanism involves both central and peripheral pathways: centrally, calcitonin receptor activation in the CNS modulates serotonergic descending pain inhibitory pathways and increases beta-endorphin levels; peripherally, it reduces prostaglandin E2 synthesis and inflammatory mediators at fracture sites. The aminosuberic acid modification at positions 1 and 7 replaces the native disulfide bridge, conferring enhanced stability against oxidative degradation while preserving full biological activity.
Research Status
approved
Half-Life
~15 minutes
Molecular Formula
C₁₄₈H₂₄₅N₄₃O₄₇
Primary Use
Bone & Joint
Table of Contents

Benefits

  • Reduces osteoporotic bone pain — significant analgesic effect on vertebral compression fracture pain, often within the first week of treatmentstrong
  • Inhibits bone resorption — measurable decrease in urinary deoxypyridinoline and NTx bone resorption markersstrong
  • Prevents bone mineral density loss — maintains or modestly increases lumbar spine BMD in postmenopausal osteoporosis over 1-2 years of treatmentmoderate
  • Treats hypercalcemia — rapidly lowers serum calcium in malignancy-associated and other hypercalcemic statesstrong
  • Superior chemical stability — aminosuberic acid bridge resists oxidative degradation better than the disulfide bond in salmon calcitoninmoderate

Dosage Protocols

RouteDosage RangeFrequencyNotes
Intramuscular injection20 units (40 mcg)Once weeklyStandard osteoporosis regimen in Japan. Administered as a deep intramuscular injection in the gluteal or deltoid muscle. Treatment typically continued for 6-12 months or longer. Calcium and vitamin D supplementation recommended concurrently.
Intramuscular injection40 units (80 mcg)Once or twice dailyHigher-dose regimen for acute hypercalcemia or Paget disease. Short-term use until calcium normalizes. Transition to lower maintenance dosing or alternative therapies as appropriate.

Medical disclaimer

Dosage information is provided for educational reference only. Always follow your prescriber's instructions and consult a qualified healthcare provider before starting any peptide protocol.

Side Effects

  • Nausea and gastrointestinal discomfort — occurs in 5-15% of patients, usually mild and transientcommon
  • Facial flushing and warmth — vasodilatory effect common to all calcitonins, typically resolves within 30 minutescommon
  • Injection site pain or induration — related to intramuscular route of administrationcommon
  • Transient hypocalcemia — excessive suppression of bone resorption can lower calcium levels, particularly in vitamin D-deficient patientsrare
  • Anaphylaxis/severe allergic reaction — rare but reported with calcitonin-class drugs; skin test recommended before first dose in Japanserious

Frequently Asked Questions

How does elcatonin compare to salmon calcitonin?
Elcatonin and salmon calcitonin share the same mechanism (calcitonin receptor agonism) and similar potency, but differ structurally. Salmon calcitonin uses a natural disulfide bond between cysteines 1 and 7, while elcatonin replaces this with a more stable aminosuberic acid bridge. This modification gives elcatonin greater chemical stability and a longer shelf life. Salmon calcitonin is available as a nasal spray (Miacalcin) globally, while elcatonin is primarily used in Japan as an intramuscular injection.
Is elcatonin available outside Japan?
Elcatonin is approved primarily in Japan and some other Asian markets. It is not FDA-approved in the United States or approved by the EMA in Europe. In Western countries, salmon calcitonin (nasal or injectable) was the calcitonin formulation of choice, though its use has declined in favor of bisphosphonates and newer agents like denosumab. Patients outside Japan typically cannot access elcatonin through standard pharmacies.
Why is elcatonin particularly useful for bone pain?
Calcitonins are unique among osteoporosis drugs in providing direct analgesic effects beyond their bone-protective action. Elcatonin reduces bone pain through multiple mechanisms: central modulation of descending pain inhibitory pathways via serotonergic neurons, increased beta-endorphin release, peripheral reduction of prostaglandin E2 at fracture sites, and inhibition of local inflammatory mediators. This makes elcatonin particularly valuable for patients with painful vertebral compression fractures who need both bone protection and pain relief.

References

  1. 1
    Calcitonin for the treatment of postmenopausal osteoporosis: comparative study of eel calcitonin (elcatonin) and salmon calcitonin(1989)PubMed ↗
  2. 2
    Analgesic effect of elcatonin on pain associated with osteoporosis: a double-blind placebo-controlled study(1996)PubMed ↗
  3. 3
    Elcatonin prevents bone loss and maintains bone quality in osteoporotic patients(1999)PubMed ↗

Latest Research

Last updated: 2026-02-19