Teriparatide and Abaloparatide: Medicine Overviews
Teriparatide (Forteo) and abaloparatide (Tymlos) are bone-building injectable medicines for osteoporosis; this page covers label indications, fracture trials, osteosarcoma questions and safety.
Content last updated . This page has not been medically reviewed.
Quick overview
Teriparatide and abaloparatide are two prescription parathyroid-hormone-related peptides used for osteoporosis. This page explains what the official labels say. It is education only. It does not give dosing, and it does not say who should use a bone medicine or whether to change one.Evidence label used here: approved medicine. The regulators named below approved each product for the indications quoted. Please also see Bone and Mineral Regulation Peptide Medicines for the wider class and Osteoporosis and Bone Health for lifestyle and general context.
Teriparatide
Active ingredient and brand. Teriparatide is sold in the US as Forteo (Eli Lilly). The FDA label calls it a parathyroid hormone analog, PTH(1-34), with initial US approval listed as 1987. The label read was the DailyMed version dated 08/2026. [1]Approved uses, United States. Treating postmenopausal women with osteoporosis at high risk for fracture, or who failed or cannot take other osteoporosis therapy; increasing bone mass in men with primary or hypogonadal osteoporosis at high risk for fracture; and treating men and women with osteoporosis linked to sustained glucocorticoid (steroid) therapy. [1]
Approved uses, European Union. The European Medicines Agency (EMA) page for Forsteo says it treats osteoporosis in postmenopausal women, in men at increased risk of fractures, and in people at increased risk because of long-term glucocorticoids. It states Forsteo reduced spine and non-spine fractures in postmenopausal women but not hip fractures. [2]
How it works. Per the label, teriparatide and the first 34 amino acids of natural parathyroid hormone bind the same receptors with the same affinity. The skeletal effect depends on the pattern of exposure: once-daily dosing stimulates new bone formation on bone surfaces. [1]
Fracture trial. In a placebo-controlled study of 1,637 postmenopausal women (median exposure 19 months, all given calcium and vitamin D), new vertebral fractures occurred in 5.0% on teriparatide versus 14.3% on placebo (relative reduction 65%). Nonvertebral fractures were 2.6% versus 5.5%. [1]
Abaloparatide
Active ingredient and brand. Abaloparatide is sold in the US as Tymlos (Radius Health). The label calls it an analog of human parathyroid-hormone-related peptide, PTHrP(1-34), with initial US approval in 2017. The DailyMed version read was dated 08/2026. [3]Approved uses, United States. Treating postmenopausal women with osteoporosis at high risk for fracture or who failed or cannot take other osteoporosis therapy, and increasing bone density in men with osteoporosis at high risk for fracture or who failed or cannot take other therapy. [3]
Approved uses, European Union. The EMA lists abaloparatide as Eladynos, for osteoporosis in postmenopausal women at increased risk of fractures. [4]
How it works. The label says abaloparatide is an agonist at the PTH1 receptor, activating a cAMP signaling pathway, and once-daily dosing stimulates new bone formation by osteoblasts. [3]
Fracture trial. In an 18-month placebo-controlled trial of postmenopausal women (824 on abaloparatide, 821 on placebo), new vertebral fractures were 0.6% versus 4.2% and nonvertebral fractures 2.7% versus 4.7% (p = 0.049). In an extension where everyone then took alendronate, the label says the vertebral fracture reduction was maintained after 24 months of open-label alendronate. [3]
Side by side
| Teriparatide (Forteo) | Abaloparatide (Tymlos) | |
|---|---|---|
| Molecule type | Analog of PTH 1-34 | Analog of PTHrP 1-34 |
| US indication in men | Increase bone mass in men with primary or hypogonadal osteoporosis; also glucocorticoid-linked osteoporosis in men and women | Increase bone density in men with osteoporosis at high risk |
| EU product | Forsteo, with men and glucocorticoid groups | Eladynos, listed for postmenopausal women |
| Common adverse reactions in labels | Arthralgia, pain, nausea (more than 10%) | In women: hypercalciuria, dizziness, nausea, headache, palpitations, fatigue |
[1][3][4] The two trials differ in design, populations and length, so their percentages should not be compared directly. No trial in these labels pits the two medicines against each other.
Monitoring and professional care
Labels frame these as specialist prescriptions with attention to calcium, vitamin D and, for Tymlos, urine calcium if hypercalciuria or stones are suspected. [1][3] Whether to use one, how long, and what comes next (the Tymlos extension study followed treatment with alendronate) are decisions for the prescriber.Off-label and investigational questions
Uses beyond the labeled bone-density indications, such as speeding fracture healing, were not evaluated for this page. Proper evidence not found in the sources checked (FDA labels and EMA pages; trial literature on other uses was not reviewed). The labels themselves state only the indications listed above. For how class names and categories differ, see Approved, Investigational and Unapproved Peptides.Frequently asked questions
Are teriparatide and abaloparatide the same medicine?
No. They are related peptides modeled on different natural molecules (PTH versus PTHrP) with different labels and brands. [1][3]
Do they cause bone cancer?
In rats, both caused osteosarcoma. In people, labels report post-marketing cases but say observational studies have not shown increased risk, with limited data past 2 years. [1][3]
Is there a lifetime limit on use?
The Tymlos label does not recommend use beyond 2 years in a lifetime. Forteo's label restricts longer use to people who remain at high fracture risk. [3][1]
Is abaloparatide approved in Europe?
The EMA lists it as Eladynos for postmenopausal women at increased fracture risk. [4]
Can I switch or stop on my own?
This page cannot advise that. Talk with your prescriber.
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Major safety information
- Osteosarcoma question. Rats given teriparatide or abaloparatide developed a dose-related increase in osteosarcoma (a malignant bone tumor). Osteosarcoma has been reported after marketing, but the labels say an increased risk has not been seen in observational human studies and data beyond 2 years are limited. [1][3] For teriparatide, two US surveillance studies found three and zero osteosarcoma cases among 379,283 and 153,316 users, with the label cautioning about data limits. [1] Animal results are not proof of the same effect in people.
- Who should avoid them. Both labels list people with open growth plates, Paget's disease, bone metastases or past bone cancer, prior skeletal radiation and hereditary bone-cancer disorders. [1][3]
- Duration. The Tymlos label says use for more than 2 years during a lifetime is not recommended. Forteo's label says use beyond 2 years should be considered only if the person remains at high fracture risk. [3][1]
- Other warnings. Allergic reactions including anaphylaxis, high blood calcium, kidney stones (urolithiasis) risk, and orthostatic hypotension (dizziness on standing, often after the first doses). [1][3] Teriparatide can raise the risk of digoxin toxicity through transient high calcium. [1]
- Children. Teriparatide's safety and effectiveness have not been established in children, and the label advises avoiding use because of higher baseline osteosarcoma risk. [1]
References
- FORTEO (teriparatide) injection, prescribing information (DailyMed label version dated 2026-08-03). Read 2026-10-22.
- EMA, Forsteo: European public assessment report overview. Read 2026-10-22.
- TYMLOS (abaloparatide) injection, prescribing information (DailyMed label version dated 2026-08-11). Read 2026-10-22.
- EMA, Eladynos: European public assessment report overview. Read 2026-10-22.