Reproductive & Hormonal
Abaloparatide
Tymlos (brand, US); Eladynos (brand, EU/GB); BA058; BIM-44058; PTHrP(1-34) analog
8 min read · Updated July 8, 2026 · 11 references
Abaloparatide is an FDA-approved (Tymlos, 2017) and EU-approved (Eladynos, 2022) prescription medicine for osteoporosis at high fracture risk. It is a PTHrP(1-34) analog that activates the PTH1 receptor to favor bone formation; its US label originally carried a boxed osteosarcoma warning (from rat studies), which the FDA removed effective 22 December 2021, though osteosarcoma cautions and a 2-year cumulative-use limit remain in the labeling. This is a licensed medicine used under medical supervision, not a research chemical, and this page is not medical advice.
Evidence: Regulator-approved drug with human trial evidence.
Approved in: US (FDA — Tymlos) and EU (Eladynos); UK (MHRA — Eladynos). Approved for osteoporosis at high fracture risk. Approval applies to the specific licensed products, not to research-grade material
- Synthetic PTHrP(1-34) analog; PTH1 receptor (PTH1R) agonist, osteoanabolic
- FDA-approved as Tymlos (2017); US indication later expanded to men (2022)
- EU initially refused by EMA (2018–2019), then approved as Eladynos (12 Dec 2022); UK MHRA (2023)
- Pivotal Phase 3 ACTIVE trial showed reduced vertebral and non-vertebral fractures and increased BMD [Human]
- US label originally carried a boxed osteosarcoma warning (rat data), removed by FDA on 22 Dec 2021; osteosarcoma cautions and a 2-year cumulative-use limit remain
- Prescription medicine used under supervision — not a research chemical; not medical advice
A synthetic 34-amino-acid analog of parathyroid hormone-related protein (PTHrP 1-34) and an approved osteoanabolic (bone-forming) medicine for osteoporosis, marketed as Tymlos (US) and Eladynos (EU/UK). Approved medicine — the approval applies to the specific licensed products, not to research-grade material.
Brand names and codes
Abaloparatide is sold as Tymlos in the United States and Eladynos in the European Union and Great Britain. It also appears in the literature under the development codes BA058 and BIM-44058, and is described chemically as a PTHrP(1-34) analog.
Overview
Abaloparatide is a synthetic 34-amino-acid peptide analog of human parathyroid hormone-related protein, PTHrP(1-34). Unlike most compounds documented on this site, it is an approved osteoanabolic (bone-forming) medicine for osteoporosis. It is marketed as Tymlos in the United States and Eladynos in the European Union and the United Kingdom, and acts as an agonist at the PTH1 receptor (PTH1R) [Human].
It was approved by the U.S. FDA (developer Radius Health) in April 2017 for postmenopausal women with osteoporosis at high risk of fracture; the U.S. indication was later expanded to men with osteoporosis at high fracture risk (2022) [Human]. In the EU the path was less direct: the EMA/CHMP initially issued a negative opinion (22 March 2018), confirmed on re-examination, leading to a European Commission refusal (7 January 2019) over insufficient non-vertebral fracture efficacy and cardiac concerns. A later application succeeded, with the European Commission granting marketing authorization for Eladynos on 12 December 2022 [Human].
Approved medicine — used under medical supervision
Abaloparatide (Tymlos / Eladynos) is a prescription osteoporosis medicine, used only under medical supervision. Regulatory approval applies to the specific licensed products, not to research-grade or "for research use only" material sold online, whose identity, purity, and sterility cannot be assumed. This page is educational and not medical advice, and it does not provide dosing guidance. Check your jurisdiction.
Chemistry and structure
Abaloparatide is a 34-residue synthetic peptide modeled on PTHrP(1-34). It contains a non-standard residue at position 29 — Aib (2-aminoisobutyric acid) — and its C-terminus is amidated, features intended to stabilize the peptide's active conformation.
| Property | Value |
|---|---|
| Sequence | Ala-Val-Ser-Glu-His-Gln-Leu-Leu-His-Asp-Lys-Gly-Lys-Ser-Ile-Gln-Asp-Leu-Arg-Arg-Arg-Glu-Leu-Leu-Glu-Lys-Leu-Leu-Aib-Lys-Leu-His-Thr-Ala-NH2 |
| Classification | Synthetic PTHrP(1-34) analog; osteoanabolic PTH1R agonist |
| Molecular formula | C174H300N56O49 (PubChem CID 76943386) |
| Molecular weight | ~3961 Da (average). Wikipedia cites 3959.649 g/mol for C174H299N56O49 (a one-hydrogen difference reflecting protonation-state convention) |
| CAS number (reported) | 247062-33-5 |
| Amino acids | 34 (position 29 = Aib; C-terminal amide) |
Molecular-weight caveat
Sources report the formula and mass with a one-hydrogen discrepancy: PubChem lists C174H300N56O49 while Wikipedia cites 3959.649 g/mol for C174H299N56O49. The widely quoted value is ~3961 Da (average). The single authoritative PubChem-computed mass and the exact protonation state could not be fully reconciled from the sources consulted; the CAS number 247062-33-5 was confirmed via Wikipedia and vendor listings but not read directly off the PubChem computed record.
Mechanism of action
- PTH1 receptor (PTH1R) agonist. Abaloparatide binds and activates PTH1R, engaging the Gs / cAMP / PKA signaling pathway in osteoblasts to drive anabolic, bone-forming signaling [Human]. (FDA label; DrugBank.)
- Receptor-conformation selectivity (proposed). It is proposed to preferentially bind/stabilize the transient "RG" conformation of PTH1R rather than the prolonged "R0" conformation favored by teriparatide, a model advanced to explain a more net-anabolic, less resorptive profile [Hypothesis]. (Trends in Endocrinology & Metabolism 2019.) A comparative study found that initial intracellular signaling engagement by teriparatide, abaloparatide and long-acting PTH was comparable, so the clinical significance of the RG-selectivity model is debated [In vitro]. (PMC8101618.)
- Net skeletal effect. The combined action is increased bone formation and reduced bone resorption, raising bone mineral density (BMD) at the lumbar spine, total hip and femoral neck [Human]. (ACTIVE Phase 3 trial; approved labeling.)
Research and evidence
| Study (year) | Model type | System | Key finding |
|---|---|---|---|
| ACTIVE trial — BA058-05-003 | Pivotal RCT [Human] | Postmenopausal women with osteoporosis | Phase 3, double-blind, placebo-controlled with open-label teriparatide comparator; reduced vertebral and non-vertebral fractures and increased BMD |
| ACTIVExtend — BA058-05-005 | Extension study [Human] | Continuation cohort | 2-year extension of the ACTIVE program |
| US claims-based cohort (>22,000) | Real-world evidence [Human] | US administrative claims | Prospectively-planned retrospective cohort that supported EU registration |
Human evidence. Abaloparatide has a strong human evidence base underpinning its approvals. The pivotal Phase 3 ACTIVE trial (BA058-05-003) in postmenopausal women with osteoporosis compared abaloparatide against placebo with an open-label teriparatide comparator, and — together with the ACTIVExtend 2-year extension (BA058-05-005) — showed reductions in vertebral and non-vertebral fractures and increases in bone mineral density [Human]. EU registration was additionally supported by a prospectively-planned retrospective observational cohort using US claims data (more than 22,000 patients) [Human, real-world evidence].
Trial citations reported via regulators/company
The ACTIVE and ACTIVExtend trial codes and findings here are as reported by the regulator (EMA EPAR) and the company (Radius Health). The primary peer-reviewed ACTIVE publication (author/journal/year) was not independently fetched in the research for this page, so treat the trial codes as reported rather than verified against the primary paper.
Status and regulation
United States (FDA — approved).
- April 2017: Initial approval of Tymlos (Radius Health) for postmenopausal women with osteoporosis at high risk of fracture.
- 2022: Indication expanded to men with osteoporosis at high fracture risk.
- The original 2017 US label carried a boxed warning for risk of osteosarcoma (based on rat carcinogenicity data). The FDA removed the boxed warning effective 22 December 2021 after reviewing post-marketing data for the PTH/PTHrP class; osteosarcoma risk information was moved to the Warnings and Precautions section. The current label still advises against use in patients at increased osteosarcoma risk and states that cumulative lifetime use of Tymlos and other PTH analogs beyond 2 years is not recommended.
European Union (EMA — initially refused, later approved).
- 22 March 2018: CHMP negative opinion, confirmed on re-examination 26 July 2018; European Commission refusal 7 January 2019, citing insufficient non-vertebral fracture efficacy and cardiac (heart-rate / palpitations) concerns.
- October 2022: CHMP positive opinion; European Commission marketing authorization for Eladynos granted 12 December 2022 for osteoporosis in postmenopausal women at increased risk of fracture.
United Kingdom (MHRA — approved). The MHRA approved Eladynos on 27 March 2023 via the EC Decision Reliance Procedure.
Regulatory facts verified as of research date 2026-07-08.
Safety
- The original 2017 US Tymlos label carried a boxed warning for osteosarcoma, derived from rat carcinogenicity studies. The FDA removed that boxed warning effective 22 December 2021; osteosarcoma cautions now appear under Warnings and Precautions, and a 2-year cumulative-lifetime-use limit for PTH/PTHrP analogs remains in the labeling [Human/label].
- EU regulators specifically flagged cardiac concerns (heart rate / palpitations) during the initial refusal period [Human/regulatory].
- Abaloparatide is a potent osteoanabolic agent that acts on PTH1R signaling and is used only under medical supervision with the monitoring built into its approved use.
Prescription medicine — not for unsupervised or research-source use
Even though abaloparatide is an approved medicine, the approval covers the specific licensed products (Tymlos / Eladynos) prescribed and monitored by a clinician. Material sold online as "research" abaloparatide is not the approved medicine, is not manufactured to pharmaceutical standards, and cannot be assumed to match its identity, potency, or sterility. Nothing here is medical advice or an endorsement of self-administration.
Legal status
Abaloparatide occupies two different statuses depending on the material and the intent:
- As a licensed pharmaceutical (Tymlos in the US; Eladynos in the EU/UK), it is a prescription-only medicine for defined osteoporosis indications, dispensed and supervised through the regulated healthcare system.
- Research-grade abaloparatide sold "for research use only" is not an approved medicine. Such classification is a supply/labeling category, not authorization for human use; a compound becomes an unauthorised medicine the moment it is intended for human use. "Research use only" is not affirmative permission to take it.
- WADA status: No source consulted asserts that abaloparatide is on the WADA Prohibited List or assigns it a class code, so its sport-prohibition status is Not established / not found in sources. WADA sport-eligibility is a separate axis from legality and is not inferred here.
This is not legal advice. Legal and prescribing status differ by country and change over time — check your jurisdiction (dated 2026-07-08).
How it compares
Abaloparatide is a PTH-pathway osteoanabolic agent, a class not otherwise represented among the peptides documented here; its most direct comparator, teriparatide (PTH 1-34), is not in this set. Among approved peptide medicines on this site:
- Liraglutide and Semaglutide are approved medicines too, but they are GLP-1 receptor agonists for diabetes/weight management — a completely different receptor system and indication.
- Tesamorelin is another approved peptide, but it acts on the GHRH / growth-hormone axis, not the PTH1 receptor.
The shared lesson is that "approved" is indication-specific: abaloparatide's evidence and approval pertain to osteoporosis and fracture risk, and do not transfer to other peptides or other uses.
Common misconceptions
| Misconception | Reality |
|---|---|
| "Abaloparatide is just teriparatide." | Both activate PTH1R, but abaloparatide is a distinct PTHrP(1-34) analog and is proposed to favor the transient RG receptor conformation [Hypothesis]; a comparative study found initial signaling engagement comparable across ligands [In vitro]. |
| "It was banned in Europe." | The EU initially refused it (2018–2019) over non-vertebral fracture efficacy and cardiac concerns, but it was later approved — Eladynos received EU marketing authorization on 12 December 2022. |
| "Approved means safe to buy and take on your own." | Approval applies to the specific licensed products used under medical supervision; the US label originally carried a boxed osteosarcoma warning (removed by the FDA in December 2021, with osteosarcoma cautions and a 2-year cumulative-use limit still in the labeling). Research-source material is not the approved medicine. |
| "It's on the WADA banned list." | No source consulted asserts this. Its WADA status is not established here, and unapproved-for-a-use is never automatically a WADA class code. |
This article is provided for educational purposes only and is not medical advice. Abaloparatide (Tymlos / Eladynos) is a prescription medicine that should be used only under the supervision of a qualified healthcare professional. Regulatory facts are dated 2026-07-08 and may change; verify against current labeling and your local regulator.
References
- 1.
- 2.TYMLOS (abaloparatide) injection — Full Prescribing Information (FDA Label) — Radius Health, Inc., FDA Drugs@FDA Label Repository, 2017. source
- 3.TYMLOS (abaloparatide) injection — current Prescribing Information (boxed warning removed 22 Dec 2021) — FDA Drugs@FDA Label Repository, 2023. source
- 4.Radius Announces Update on TYMLOS (abaloparatide) Label — FDA removes boxed warning — Radius Health, Inc., BioSpace (company announcement), 2021. source
- 5.
- 6.European Commission Approves ELADYNOS (abaloparatide) for osteoporosis in postmenopausal women at increased risk of fracture — Radius Health / Theramex, Radius Pharmaceuticals (press release), 2022. source
- 7.
- 8.
- 9.Handling PTH1R in Skeletal Diseases: Abaloparatide — Trends in Endocrinology & Metabolism, 2019. source
- 10.Comparable Initial Engagement of Intracellular Signaling Pathways by PTHR Ligands — PMC (PMC8101618). source
- 11.Real-World Evidence to Support the Registration of a New Osteoporosis Medicinal Product in Europe — PMC (PMC11043175). source
Frequently asked questions
- What is Abaloparatide?
- A synthetic 34-amino-acid analog of parathyroid hormone-related protein (PTHrP 1-34) and an approved osteoanabolic (bone-forming) medicine for osteoporosis, marketed as Tymlos (US) and Eladynos (EU/UK). Approved medicine — the approval applies to the specific licensed products, not to research-grade material.
- Is Abaloparatide approved as a medicine, and where?
- It is an approved prescription medicine, but where it is approved matters: US (FDA — Tymlos) and EU (Eladynos); UK (MHRA — Eladynos). Approved for osteoporosis at high fracture risk. Approval applies to the specific licensed products, not to research-grade material. It should only be used under medical supervision.
- What is Abaloparatide studied for?
- Abaloparatide is most often discussed in the context of longevity & cellular health. Research has examined PTH1 receptor (PTH1R) signaling, Osteoanabolic bone formation, and Bone mineral density / fracture prevention. Being studied for an area does not mean it is proven or approved for it.
- Does Abaloparatide have human clinical trials?
- Yes. Abaloparatide has been studied in human clinical trials and is an approved medicine in at least some regions.
Educational disclaimer. This article summarizes published research for informational purposes and is not medical advice. Abaloparatide is a research chemical not approved for human use. Consult a qualified healthcare professional before making health decisions.