Abaloparatide — Research, Dosing & Price Guide

Abaloparatide is a synthetic 34-amino-acid analog of parathyroid hormone-related protein (PTHrP) that potently stimulates new bone formation. FDA-approved in 2017 under the brand name Tymlos for the treatment of osteoporosis in postmenopausal women at high fracture risk, it represents a second-generation approach to anabolic bone therapy with advantages over teriparatide in certain clinical parameters.

Abaloparatide selectively activates the PTH1 receptor (PTH1R), preferentially binding its RG (G-protein coupled) conformation over the R0 (G-protein independent) conformation. This receptor selectivity is clinically significant: RG activation drives anabolic signaling (osteoblast stimulation, new bone formation) while R0 activation is associated with bone resorption and calcium mobilization. By favoring RG, abaloparatide achieves a more favorable anabolic window than teriparatide — more bone building, less bone breakdown, and less hypercalcemia. At the cellular level, RG-selective activation stimulates adenylyl cyclase in osteoblasts, increasing cAMP and activating protein kinase A (PKA). This drives the expression of osteoblast differentiation markers including RUNX2, osterix, and osteocalcin, while simultaneously activating the Wnt/β-catenin signaling pathway to promote osteoblast survival and proliferation. The net result is rapid increases in bone formation markers (P1NP) with only modest increases in resorption markers (CTX), creating a wide anabolic window. Abaloparatide also stimulates periosteal bone formation, improving both trabecular and cortical bone geometry.

• The ACTIVE trial (n=2,463 postmenopausal women) demonstrated abaloparatide reduced new vertebral fractures by 86% and nonvertebral fractures by 43% compared to placebo over 18 months.
• Head-to-head comparison with teriparatide in the ACTIVE trial showed comparable vertebral fracture reduction but significantly lower rates of hypercalcemia (3.4% vs. 6.4%).
• The ACTIVExtend follow-up study showed that patients transitioning from abaloparatide to alendronate maintained fracture protection and continued BMD increases for an additional 24 months.
• Bone mineral density increased by 11.2% at the lumbar spine and 4.2% at the total hip after 18 months of treatment — among the highest BMD gains reported for any osteoporosis therapy.
• Abaloparatide demonstrated faster onset of bone formation marker increases (P1NP elevated within 1 month) compared to teriparatide.
• Post-hoc analyses showed significant reduction in major osteoporotic fractures and clinical fractures across multiple skeletal sites.

• FDA-approved dose: 80 mcg subcutaneous injection once daily, administered in the periumbilical (around the navel) region of the abdomen.
• Rotate injection sites daily to minimize injection site reactions. Alternate left and right sides of the abdomen.
• Maximum recommended treatment duration: 2 years (based on osteosarcoma signal in rat studies at supratherapeutic doses).
• Following abaloparatide treatment, transition to an antiresorptive agent (bisphosphonate such as alendronate 70 mg weekly) to consolidate and maintain bone density gains.
• Inject at the same time each day for consistency. No specific food timing requirements.
• Allow the pre-filled pen to reach room temperature before injection (remove from refrigerator 30 minutes prior). Do not warm artificially.
• If a dose is missed, administer it as soon as remembered on the same day. Do not double-dose.

Known Side Effects

• Hypercalcemia — mild and transient elevations in serum calcium reported in approximately 3.4% of patients. Less frequent than with teriparatide.
• Injection site reactions — redness, swelling, or pain at injection site, occurring in up to 16% of patients. Usually mild and self-resolving.
• Dizziness — reported in 10% of patients, typically within 4 hours of injection. Related to transient blood pressure changes. Patients should inject while seated.
• Nausea — affects approximately 8% of patients, most common during the first month of treatment and tends to diminish.
• Tachycardia/palpitations — transient heart rate increases reported, usually within the first hour post-injection.
• Headache — reported by approximately 8% of patients in clinical trials.
• Orthostatic hypotension — a drop in blood pressure upon standing may occur shortly after injection. Recommend sitting or lying down for the first dose.

Safety Profile

Abaloparatide carries a boxed warning regarding osteosarcoma risk based on findings in Fischer 344 rats exposed to high doses for near-lifetime durations. However, this risk has not been observed in humans, and the rat strain used is uniquely susceptible to bone tumors. The 2-year treatment limitation is precautionary. It is contraindicated in patients with Paget's disease of bone, unexplained elevated alkaline phosphatase, open epiphyses (children/adolescents), prior radiation therapy involving the skeleton, pre-existing hypercalcemia, or bone metastases. Drug interactions are minimal, but concurrent use with digoxin requires monitoring due to potential hypercalcemia effects on cardiac glycoside sensitivity. Patients with renal impairment (eGFR <30 mL/min) should use with caution as calcium excretion may be impaired. The overall clinical safety profile is well-characterized from Phase III trials involving over 3,500 patients.

Month 1: Bone formation markers (P1NP) begin rising within the first 2–4 weeks. Injection site reactions are most common during this period. Mild dizziness after injection may occur as the body adjusts. Months 2–6: Bone mineral density increases become measurable on DXA scans. Most patients tolerate injections well by this point. Calcium levels should be monitored periodically. Months 7–12: Significant BMD gains are typically evident, with lumbar spine showing the most dramatic increases. Fracture risk reduction is well-established by this point. Side effects have generally plateaued or resolved. Months 13–18+: Continued BMD accrual, though the rate of gain may slow. Planning for transition to antiresorptive therapy should begin before the 24-month treatment limit.

Prices sourced from peptides.gg marketplace. Prices may vary.