Parathyroid Hormone 1-34 (Teriparatide)
Also known as: Forteo, PTH(1-34), Rheumatoid bone loss treatment
Overview
Teriparatide (Forteo) is a synthetic 34-amino acid N-terminal fragment of human parathyroid hormone (PTH) representing the biologically active portion of the full 84-amino acid hormone. Unlike full-length PTH or bisphosphonates that reduce bone resorption, teriparatide is an anabolic bone agent that actually stimulates new bone formation when administered as once-daily injections (as opposed to continuous infusion, which causes resorption). FDA-approved in 2002 for osteoporosis in postmenopausal women, men, and glucocorticoid-induced osteoporosis at high fracture risk, teriparatide typically increases lumbar spine BMD by 9–13% and reduces vertebral fracture risk by 65%.
Mechanism of Action
Teriparatide binds PTH receptor 1 (PTH1R), a class B GPCR expressed on osteoblasts, osteoclasts, and renal tubular cells. Intermittent (pulsatile) PTH1R activation on osteoblasts paradoxically stimulates bone formation by: (1) reducing osteoblast apoptosis via anti-apoptotic signaling; (2) activating quiescent lining cells to become active osteoblasts; (3) stimulating osteoblast precursor differentiation; (4) inhibiting the expression of sclerostin and DKK1 (Wnt signaling inhibitors), thereby activating Wnt-mediated osteogenesis. Net effect: anabolic bone formation exceeds bone resorption in the intermittent dosing regimen.
Potential Benefits
- Anabolic bone formation (unique mechanism vs. antiresorptive drugs)
- 65% reduction in vertebral fracture risk
- 35–53% reduction in nonvertebral fracture risk
- FDA-approved for multiple osteoporosis indications
- Effective in glucocorticoid-induced osteoporosis
- Can re-anabolize bone even after prolonged antiresorptive treatment
Dosage Protocols
The following reflects doses used in published research studies. This is not medical advice. Consult a qualified healthcare professional.
| Beginner | 20 mcg SC daily (only approved dose) |
| Intermediate | 20 mcg SC daily |
| Advanced | 20 mcg SC daily — do not exceed |
| Cycle Duration | Maximum 24 months lifetime (FDA label) |
FDA-approved (Forteo, 2002). Anabolic osteoporosis therapy. Black box warning (rodent osteosarcoma) — limit to 2 years lifetime.
Use our Reconstitution Calculator to determine exact syringe units for your protocol.
Routes of Administration
Subcutaneous Injection (pen) ~95%
Inject into thigh or abdominal wall. Pre-filled multi-dose pen, once daily.
Read our full Routes of Administration Guide for detailed comparison of all delivery methods.
Stacking Protocols
Popular research stacks involving Parathyroid Hormone 1-34 (Teriparatide):
Osteoporosis Anabolic → Antiresorptive Sequence
Standard practice: follow 2-year anabolic teriparatide course with antiresorptive therapy to lock in BMD gains.
Teriparatide + Denosumab (DATA trial)
Combination shown in DATA study to produce greater BMD gains than monotherapy.
Explore our complete Peptide Stacking Guide for more combinations and safety considerations.
Reconstitution
| Storage | Refrigerate pen at 2-8°C. Do not freeze. Discard 28 days after first use. |
|---|
No reconstitution. Recap pen and return to fridge between doses.
Need exact syringe measurements?
Amino Acid Sequence
Ser-Val-Ser-Glu-Ile-Gln-Leu-Met-His-Asn-Leu-Gly-Lys-His-Leu-Asn-Ser-Met-Glu-Arg-Val-Glu-Trp-Leu-Arg-Lys-Lys-Leu-Gln-Asp-Val-His-Asn-Phe (34 AA)
Side Effects & Safety
- Nausea, dizziness, leg cramps
- Transient hypercalcemia
- Orthostatic hypotension
- Black box warning: osteosarcoma risk (based on rat data; not confirmed in humans)
- Contraindicated in patients at high osteosarcoma risk (Paget's disease, prior radiation)
Safety & Contraindications
This information is for educational purposes only. Consult a qualified healthcare provider before using any peptide.
Pregnancy / Lactation
Bleeding Disorders
Active Skin Infection at Injection Site
FDA Safety Information
FDA previously carried a boxed warning for osteosarcoma risk observed in rats; the boxed warning was removed in 2020 but the risk is still described in labeling. Contraindicated in patients at increased baseline risk of osteosarcoma.
Pharmacokinetics
| Half-Life | ~1 hour |
|---|---|
| Storage | Refrigerate pens at 2-8°C. Do not freeze. Protect from light. Discard 28 days after first use. |
Synergistic Compounds
The following compounds have been studied alongside Parathyroid Hormone 1-34 (Teriparatide) for potential complementary or synergistic effects:
Learn More
References & Further Reading
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