Elcatonin
A weekly calcitonin injection that strengthens the spine on scans and eases fracture pain, without proving it prevents fractures
Elcatonin is a synthetic version of eel calcitonin, a hormone that slows bone breakdown, with its ring stabilised by a carbon bridge. It is injected once a week in Japan and China for osteoporosis and the back pain of spinal fractures. Its largest trial raised spine density but did not reduce fractures.
What is it?
Calcitonin is a thyroid hormone that slows osteoclasts, the cells that break down bone. Fish calcitonins are more potent in people than the human hormone, so salmon and eel versions became drugs. Elcatonin is the eel version with its disulfide ring replaced by a stable carbon bridge.
Its strongest trial is a Japanese study in 869 postmenopausal women given 20 units or placebo weekly for three years. Spine density rose more with elcatonin, but new vertebral and other fractures were not reduced. Calcitonins fell out of favour in Europe after the EMA in 2012 limited their long-term use over a possible cancer risk; a five-year follow-up of the Japanese trial found cancer rates of 1.02 and 1.08 per 100 person-years with elcatonin and placebo.
Where elcatonin stands out is pain. In two open randomised Japanese trials in women with fresh vertebral fractures, weekly injections relieved back pain and improved mobility more than anti-inflammatory tablets.
At a Glance
Every value in this table is printed from the Grey Peptides dataset, the same record the compound explorer and comparison tool read, so the three can never disagree.
Educational information, not medical advice. The doses on this page come from approved labels, published studies and, where no study exists, amounts reported by users. None is a recommendation for you. An unapproved compound has no established safe or effective human dose, and products sold for “research use only” are not made or tested for people. Talk to a doctor before acting on anything on this site, including before you start, stop or change any medicine or dose. Full medical disclaimer.
Published Research
Trials whose titles name elcatonin, read from their PubMed abstracts on October 4, 2026; a retracted 2022 trial of alendronate with elcatonin is not cited.
Three years against placebo
869 postmenopausal women with osteoporosis received 20 units or placebo intramuscularly once a week for 144 weeks. Lumbar density rose significantly more with elcatonin, but new vertebral and non-vertebral fractures were not reduced; adverse reactions were more frequent, with no new safety concerns.
Cancer follow-up
After the EMA's 2012 warning, 645 participants of the three-year trial were followed for five years from the start: cancer incidence was 1.02 per 100 person-years with elcatonin and 1.08 with placebo. The authors note the numbers are too small to rule out a risk.
Acute back pain after vertebral fracture
228 Japanese women (mean age 77) with new vertebral fractures received weekly 20-unit injections or NSAID tablets for six weeks. Pain, disability and osteoporosis-specific function scores improved more with elcatonin at four and six weeks.
Pain and bone resorption over six months
In an open randomised trial in 107 women aged 55 and over with fresh vertebral fractures, intramuscular elcatonin beat an NSAID plus active vitamin D on pain, daily activities and quality of life from one month, lowered the resorption marker TRACP-5b and raised bone density more.
Against teriparatide in China
In 453 Chinese postmenopausal women, daily teriparatide for 18 months raised lumbar density far more than weekly elcatonin for 12 months (9.5% against 2.9% at 18 months), with similar pain relief; clinical fractures were 5.4% and 3.2%, not significantly different.
Added to risedronate for chronic back pain
45 postmenopausal women with chronic back pain were randomised to risedronate alone or with elcatonin for six months; pain scores and mental-health quality of life improved in the combined group.
Side Effects & Contraindications
Reported Side Effects
From the trials above.
Contraindications & Cautions
No US or EU label exists.
Legal Status
Used in Japan and China; not approved in the US or EU.
Frequently Asked Questions
?What is elcatonin?
A synthetic eel calcitonin with a carbon bridge in place of its disulfide ring, injected weekly for osteoporosis and fracture pain, mainly in Japan.
?Does elcatonin prevent fractures?
Not in its largest trial: over three years it raised spine density but did not reduce new fractures compared with placebo.
?Does elcatonin help back pain after a vertebral fracture?
In two open randomised Japanese trials it relieved pain and improved mobility more than anti-inflammatory tablets.
?Is calcitonin linked to cancer?
The EMA limited long-term calcitonin use in 2012 over a cancer signal; a five-year follow-up of the Japanese elcatonin trial found no difference, but was too small to rule one out.
References
- [other] PubChem CID 53395169, Elcatonin: formula C148H244N42O47, molecular weight 3363.8. Read October 4, 2026. https://pubchem.ncbi.nlm.nih.gov/compound/53395169
- [clinical-trial] Sugimoto T, et al. "A randomized, double-blind, placebo-controlled study of once weekly elcatonin in primary postmenopausal osteoporosis." Curr Med Res Opin, 2019;35(3):447-454. PMID: 29986611.
- [pubmed] Okamoto H, et al. "Association between elcatonin use and cancer risk in Japan: A follow-up study after a randomized, double-blind, placebo-controlled study of once-weekly elcatonin in primary postmenopausal osteoporosis." Osteoporos Sarcopenia, 2020;6(1):15-19. PMID: 32226828.
- [clinical-trial] Endo N, et al. "Effect of elcatonin versus nonsteroidal anti-inflammatory medications for acute back pain in patients with osteoporotic vertebral fracture: a multiclinic randomized controlled trial." J Bone Miner Metab, 2017;35(4):375-384. PMID: 27465912.
- [clinical-trial] Tanaka S, et al. "Effectiveness of elcatonin for alleviating pain and inhibiting bone resorption in patients with osteoporotic vertebral fractures." J Bone Miner Metab, 2017;35(5):544-553. PMID: 27830386.
- [clinical-trial] Li Y, et al. "Comparison of parathyroid hormone (1-34) and elcatonin in postmenopausal women with osteoporosis: an 18-month randomized, multicenter controlled trial in China." Chin Med J (Engl), 2013;126(3):457-63. PMID: 23422107.
- [clinical-trial] Hongo M, et al. "Additive effect of elcatonin to risedronate for chronic back pain and quality of life in postmenopausal women with osteoporosis: a randomized controlled trial." J Bone Miner Metab, 2015;33(4):432-9. PMID: 25123562.
- [other] RAD-AR Council Japan, drug information sheet based on Japanese regulatory approvals: Elcitonin Inj. 20S Dispo (elcatonin), for pain due to osteoporosis, usually intramuscular once a week. Read October 5, 2026.
Sources & Citations
Trials from their PubMed abstracts, October 4, 2026; formula from PubChem; US and EU status from Drugs@FDA and the EMA medicines list the same day.
Medical Disclaimer: This content is for educational and informational purposes only. It is not medical advice, and nothing here is an instruction to obtain or use any compound. Consult a licensed healthcare provider before making health decisions.