Teriparatide
Also known as: PTH 1-34, Forteo, rhPTH(1-34), Parathyroid Hormone Fragment
PTH(1-34) | Bone-Building Anabolic Peptide
Overview
Teriparatide is an FDA-approved anabolic bone-building agent consisting of the first 34 amino acids of parathyroid hormone. Unlike antiresorptive osteoporosis drugs that slow bone loss, teriparatide actively stimulates new bone formation. The key to its mechanism is intermittent exposure: while continuous PTH causes bone resorption, daily injections stimulate osteoblasts more than osteoclasts, resulting in net bone formation. Clinical trials show 8% spine bone density increases and 65% reduction in vertebral fractures.
Key benefits
- FDA-approved for osteoporosis treatment
- Actively builds new bone (anabolic)
- Increases spine bone density by 5-9%
- Reduces vertebral fracture risk by 65%
- Reduces nonvertebral fractures by 35%
- Works differently than antiresorptive drugs
- Benefits seen within 3 months
- Creates 'anabolic window' for bone growth
Mechanism of action
Teriparatide binds to PTH type 1 receptors (G-protein coupled receptors) on osteoblasts, osteocytes, and renal tubular cells. This activates PKA and PKC signaling pathways that promote osteoblast activity. The intermittent daily dosing creates an 'anabolic window' where bone formation exceeds resorption. Teriparatide upregulates IGF-1 and FGF2 expression, stimulates bone formation on trabecular and cortical surfaces, and increases bone mineral density through preferential osteoblast stimulation.
Molecular data
- Type
- Recombinant PTH fragment
- Half-life
- ~1 hour (subcutaneous); ~5 minutes (intravenous)
Sequence
N-terminal 1-34 of parathyroid hormone
Indications
What the research community uses this compound for, with self-reported effectiveness.
Osteoporosis (FDA-Approved)
Bone Health Research
Dosing protocols
Common protocols by delivery method. Adjust the curve below to model accumulation in your own cycle.
Delivery method
| Protocol | Dose | Frequency | Duration |
|---|---|---|---|
| — | 20 mcg | Once daily | — |
Safety
Reported adverse effects, contraindications, and what to monitor on cycle.
Common side effects
- Injection site reactions
- Nausea
- Headache
- Leg cramps
- Dizziness
- Joint pain
Rare side effects
- Hypercalcemia
- Orthostatic hypotension
- Hypercalciuria
- Osteosarcoma (theoretical - seen in rats at high doses)
Contraindications
- Paget's disease of bone
- Prior skeletal radiation therapy
- History of skeletal malignancies
- Metabolic bone diseases other than osteoporosis
- Pre-existing hypercalcemia
- Pregnancy
Monitoring
- Serum calcium levels
- Bone mineral density testing
- Treatment limited to 2 years maximum
- Follow with antiresorptive therapy to maintain gains