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)
Postmenopausal Osteoporosis
Most effectiveFDA-approved for women with osteoporosis at high risk of fracture.
Male Osteoporosis
Most effectiveFDA-approved for men with primary or hypogonadal osteoporosis at high risk.
Glucocorticoid-Induced Osteoporosis
EffectiveFDA-approved for men and women with osteoporosis from sustained corticosteroid use.
Bone Health Research
Fracture Healing
ModerateResearch interest in accelerating fracture healing and bone repair.
Dental Bone Regeneration
ModerateInvestigated for jawbone regeneration in dental applications.
Dosing protocols
Common protocols by delivery method. Adjust the curve below to model accumulation in your own cycle.
Injectable
Teriparatide is administered as a once-daily subcutaneous injection, typically in the thigh or abdomen. It comes in pre-filled pen devices (Forteo) containing a 28-day supply. Treatment is typically limited to 2 years due to theoretical bone cancer risk from long-term use (seen only in rats at high doses).
| Protocol | Dose | Frequency | Route / duration |
|---|---|---|---|
| Osteoporosis treatment | 20 mcg | Once daily | SubQ (thigh or abdomen) |
Preparation
You will need
- Pre-filled pen device (Forteo)
- Pen needles
- Alcohol swabs
Steps
- Store pen refrigerated (do not freeze)
- Allow to reach room temperature before injection
- Attach new needle for each injection
- Inject subcutaneously in thigh or abdomen
- Discard pen after 28 days even if medication remains
Work out the water volume and syringe units in the reconstitution calculator →
Interactions
Pairwise interactions with other compounds you might be cycling — the same data behind the cycle builder's safety check.
Bisphosphonates
TimingAntiresorptive agents often needed after teriparatide to maintain bone gains. Can be used sequentially.
Calcium/Vitamin D
SynergisticAdequate calcium and vitamin D intake recommended during teriparatide therapy.
BPC-157
CompatibleDifferent mechanisms; no known interactions.
TB-500
CompatibleDifferent mechanisms; no known interactions.
Timeline
Typical week-by-week effects reported in clinical and observational data.
- Month 1-3
Bone formation begins; spine BMD increases
- Month 3-6
Continued bone density improvements
- Month 6-12
5-9% spine BMD increase; fracture risk reduction
- Year 1-2
Maximum benefits achieved; transition to maintenance
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)
Stop signs — stop and seek advice
- Signs of hypercalcemia (confusion, fatigue, nausea)
- Persistent bone pain
- Allergic reactions
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
Quality checks
What a legitimate product looks like, what should give pause, and what should make you stop.
Good signs
- Clear, colorless solution
- Pharmaceutical grade (Forteo)
- Proper cold chain maintained
- Intact pen device
Warning signs
- Research-grade products lack FDA oversight
- Temperature excursions may affect potency
Stop signs — don't use
- Cloudy or discolored solution
- Particulates visible
- Exposed to freezing or high temperatures
References
Primary literature and clinical-trial data informing this entry.
Teriparatide
StatPearls (NCBI Bookshelf) · 2024
Intermittent PTH exposure induces bone formation more than resorption; FDA-approved for osteoporosis.
The effect of teriparatide therapy on bone density in men with osteoporosis
PubMed · 2002
Spine BMD increased 5.9% (20mcg) and 9.0% (40mcg); femoral neck increased 1.5-2.9%.
Teriparatide: 2.5 Years of Experience
Journal of Bone and Mineral Research · 2006
Reduced vertebral fractures by 65% and nonvertebral fractures by 35% after 20 months.
Parathyroid Hormone (1-84) and Teriparatide in Postmenopausal Osteoporosis
Women's Health · 2006
Initial formation without resorption creates 'anabolic window' for rapid bone volume increase.
Last updated . How this page was sourced is described in the methodology.