Quick summary
Abaloparatide (Tymlos) is an FDA-approved PTHrP analog that preferentially stimulates bone formation, reducing vertebral fractures by 86% and non-vertebral fractures by 43% in the ACTIVE trial. Indicated for high-risk osteoporosis.
Overview
Abaloparatide is a 34-amino acid synthetic analog of parathyroid hormone-related protein (PTHrP) approved by the FDA under the brand name Tymlos for treating osteoporosis in postmenopausal women and men at high fracture risk. It is an anabolic agent that preferentially stimulates bone formation with minimal increase in bone resorption, distinguishing it from antiresorptive therapies. FDA approval was granted in 2017.
Mechanism of action
Abaloparatide acts as a selective agonist at the PTH1 receptor (PTH1R), activating the Gs-protein–mediated cyclic adenosine monophosphate (cAMP) signaling pathway in osteoblasts. Compared to teriparatide (PTH 1-34), abaloparatide shows greater selectivity for the RG conformation of PTH1R, which is associated with transient cAMP signaling and predominantly anabolic bone effects. This selectivity reduces prolonged receptor activation that drives osteoclast coupling and bone resorption. The net result is increased osteoblast activity, stimulation of new bone formation on trabecular and cortical surfaces, and improved bone mineral density (BMD) with a relatively favorable bone formation-to-resorption ratio compared to teriparatide.
Dosing protocols
| Purpose | Route | Dosage | Frequency | Notes |
|---|---|---|---|---|
| Osteoporosis — bone formation | subcutaneous | 80–80 mcg | once daily | Inject into periumbilical abdomen. Administer initially in a setting where patient can sit or lie down if dizziness occurs. Maximum duration 2 years lifetime; follow with antiresorptive therapy. |
Dosing information is for educational purposes only. Consult a qualified healthcare professional before using any peptide.
Research summary
The pivotal ACTIVE trial (n=2,463) demonstrated abaloparatide 80 mcg daily reduced vertebral fracture risk by 86% and non-vertebral fracture risk by 43% versus placebo over 18 months. Head-to-head comparison with teriparatide showed significantly greater improvements in total hip and femoral neck BMD. The ACTIVExtend extension study confirmed durable fracture protection after transitioning to alendronate. Markers of bone formation (P1NP) increased rapidly, while resorption markers (CTX) showed a lesser rise than with teriparatide, supporting the favorable anabolic window hypothesis.[1][2][3][4][5]
Evidence grading
Each claimed benefit is graded by the strength of available evidence. Grades reflect study quality, not effect size.
Strong = multiple RCTs · Moderate = limited trials or observational · Preliminary = animal or in vitro only · Insufficient = anecdotal or no published data
Side effects
Side effects vary by individual. This is not an exhaustive list. Report unusual symptoms to a healthcare professional.
Common stacks
Peptides commonly paired with Abaloparatide for synergistic effects.
Legal status
FDA-approved (NDA 208743, 2017) for treatment of osteoporosis in postmenopausal women and men at high risk for fracture, defined as history of fracture, multiple risk factors, or failure/intolerance of other osteoporosis therapy. Prescription-only; limited to 2-year cumulative lifetime use.
Sourcing & access
Prescription required
Abaloparatide is an FDA-approved prescription medication available through licensed healthcare providers, telehealth platforms, and 503A/503B compounding pharmacies.
Frequently asked questions
Abaloparatide (Tymlos) is a 34-amino acid synthetic analog of parathyroid hormone-related protein (PTHrP) approved by the FDA in 2017 for treating osteoporosis in postmenopausal women and men at high fracture risk. It is an anabolic bone-building agent.
Abaloparatide shows greater selectivity for the RG conformation of the PTH1 receptor, associated with transient cAMP signaling and predominantly anabolic effects. This reduces bone resorption relative to teriparatide, giving a more favorable bone formation-to-resorption ratio.
The ACTIVE trial of 2,463 patients showed abaloparatide reduced vertebral fractures by 86 percent and non-vertebral fractures by 43 percent versus placebo over 18 months, with greater hip and femoral neck BMD improvements compared to teriparatide.
Common side effects include hypercalciuria, dizziness from orthostatic hypotension, nausea, headache, palpitations, injection site reactions, upper abdominal pain, and fatigue. Patients should be able to sit or lie down after initial doses in case of orthostatic symptoms. Cumulative lifetime use is limited to 2 years, after which patients typically transition to an antiresorptive therapy such as alendronate to preserve bone gains.
Research references
- Effect of Abaloparatide vs Placebo on New Vertebral Fractures in Postmenopausal Women With Osteoporosis: A Randomized Clinical Trial (ACTIVE)PubMed
- Abaloparatide: A Review of Preclinical and Clinical StudiesPubMed
- The Efficacy and Safety of Abaloparatide-SC in Men With Osteoporosis: A Randomized Clinical TrialPubMed
- Abaloparatide for Risk Reduction of Nonvertebral and Vertebral Fractures in Postmenopausal Women with Osteoporosis: A Network Meta-AnalysisPubMed
- Abaloparatide: Review of a Next-Generation Parathyroid Hormone AgonistPubMed