Teriparatide (PTH Analog)
Recombinant human PTH(1-34), an approved anabolic osteoporosis therapy that increases bone formation with intermittent daily injection.
Overview
Teriparatide is a recombinant human parathyroid hormone fragment, PTH(1-34), containing the N-terminal 34 amino acids of the 84-amino-acid hormone. It is an approved anabolic osteoporosis therapy (Forteo and related products) that increases bone formation when given intermittently by daily injection. It is the most clinically established bone-anabolic peptide.
Mechanism
PTH acts through the PTH1 receptor on osteoblasts and osteocytes. The anabolic response depends on the mode of exposure: intermittent low-dose administration favors bone formation, whereas continuous exposure favors resorption. Daily teriparatide therefore shifts the bone-remodeling balance toward net formation, improving bone mass and microarchitecture.
Dosing
Approved dosing is a fixed daily subcutaneous injection (20 mcg per the label) with a limit on cumulative lifetime exposure. Research use in animal models follows species-specific intermittent protocols to reproduce the anabolic profile.
- Daily subcutaneous injection is the approved schedule
- The label limits cumulative lifetime exposure to approximately 24 months
- Animal models use intermittent injection to reproduce the anabolic pattern
Expected Effects
- Increased bone mineral density at the spine and hip in clinical trials
- Reduced vertebral and nonvertebral fracture risk in postmenopausal osteoporosis
- Improved bone-formation markers and trabecular architecture
Side Effects & Tolerability
Common side effects include injection-site reactions, leg cramps, dizziness, and transient hypercalcemia. The label carries a boxed warning about dose-dependent osteosarcoma observed in rats, which has not been confirmed in human use, and the drug is contraindicated in conditions associated with elevated bone-tumor risk, such as Paget disease or prior skeletal radiation.
Storage
Approved products require refrigeration and protection from light. Lyophilized research peptide should be stored cold and desiccated per the supplier certificate of analysis.