Teriparatide — Complete Research Guide (2026)

Last updated 2026-06-30

What is Teriparatide?

Teriparatide is recombinant human parathyroid hormone fragment PTH(1-34), the anabolic (bone-building) osteoporosis drug sold as Forteo (US) and Forsteo (EU). It is approved to treat osteoporosis at high fracture risk in postmenopausal women and men, and glucocorticoid-induced osteoporosis.

Its efficacy rests on the pivotal Neer 2001 NEJM fracture-prevention randomized trial and later active-comparator RCTs against alendronate and risedronate.

How does Teriparatide work?

Given as a once-daily injection, teriparatide produces intermittent (pulsatile) exposure to PTH, which stimulates osteoblasts and net bone formation, unlike continuous PTH exposure which favors resorption.

It works largely by prolonging osteoblast survival and increasing osteoblast number, improving bone mass and microarchitecture. [INFOGRAPHIC: Intermittent PTH anabolic bone formation]

What does the research say about Teriparatide?

• In postmenopausal osteoporosis, teriparatide 20 mcg/day reduced new vertebral fractures by about 65% and nonvertebral fragility fractures by about 53% versus placebo. ^[1]
• In glucocorticoid-induced osteoporosis, new vertebral fractures occurred in only 0.6% of teriparatide patients versus 6.1% on alendronate over 18 months (P=0.004). ^[3]
• In women with severe osteoporosis (VERO), new vertebral fractures occurred in 5.4% on teriparatide versus 12.0% on risedronate (risk ratio 0.44). ^[4]

Clinical research & studies

The references below are the primary sources cited throughout this guide. Each links directly to PubMed or the regulator. Where evidence is preclinical (animal or in-vitro), that is stated rather than implied.

• [1] Effect of parathyroid hormone (1-34) on fractures and bone mineral density in postmenopausal women with osteoporosis — Neer RM et al., N Engl J Med 2001. (RCT n=1637)
• [2] A randomized double-blind trial to compare the efficacy of teriparatide [recombinant human parathyroid hormone (1-34)] with alendronate in postmenopausal women with osteoporosis — Body JJ et al., J Clin Endocrinol Metab 2002. (RCT n=146)
• [3] Teriparatide or alendronate in glucocorticoid-induced osteoporosis — Saag KG et al., N Engl J Med 2007. (RCT n=428)
• [4] Effects of teriparatide and risedronate on new fractures in post-menopausal women with severe osteoporosis (VERO): a multicentre, double-blind, double-dummy, randomised controlled trial — Kendler DL et al., Lancet 2018. (RCT n=1360 (VERO))
• [5] Molecular and cellular mechanisms of the anabolic effect of intermittent PTH — Jilka RL, Bone 2007. (review)

Dosing context

The approved product is delivered as 20 mcg injected subcutaneously once daily from a multidose pen.

Treatment is initiated and monitored by a clinician; this is descriptive product context, not a personal dosing recommendation.

Side effects & safety profile

Common adverse effects include transient hypercalcemia, nausea, headache, dizziness, leg cramps and orthostatic hypotension after the first doses.

Teriparatide originally carried an FDA boxed warning about osteosarcoma seen in rat studies and a 2-year lifetime-use limit; the FDA removed both the boxed warning and the cumulative-duration limit in November 2020, but the drug is still contraindicated or to be avoided in people at increased baseline osteosarcoma risk (Paget's disease of bone, prior skeletal radiation, unexplained high alkaline phosphatase, open growth plates, or bone metastases).

It should not be used in patients with pre-existing hypercalcemia.

Stacking & combinations

Anabolic teriparatide is typically followed by, rather than combined with, an antiresorptive such as a bisphosphonate or denosumab to preserve the bone gained, since concurrent alendronate can blunt its anabolic effect.

Finding Teriparatide vendors

User reviews

Frequently asked questions

References

1. [1] Effect of parathyroid hormone (1-34) on fractures and bone mineral density in postmenopausal women with osteoporosis — Neer RM et al., N Engl J Med 2001. PMID: 11346808. View sourceStudy: RCT n=1637Teriparatide 20 mcg reduced new vertebral fractures by 65% and nonvertebral fragility fractures by 53% versus placebo.
2. [2] A randomized double-blind trial to compare the efficacy of teriparatide [recombinant human parathyroid hormone (1-34)] with alendronate in postmenopausal women with osteoporosis — Body JJ et al., J Clin Endocrinol Metab 2002. PMID: 12364430. View sourceStudy: RCT n=146Teriparatide raised lumbar-spine BMD more than alendronate (about 12.2% vs 5.6%) with fewer nonvertebral fractures.
3. [3] Teriparatide or alendronate in glucocorticoid-induced osteoporosis — Saag KG et al., N Engl J Med 2007. PMID: 18003959. View sourceStudy: RCT n=428New vertebral fractures occurred in 0.6% on teriparatide vs 6.1% on alendronate (P=0.004), with larger spine BMD gains.
4. [4] Effects of teriparatide and risedronate on new fractures in post-menopausal women with severe osteoporosis (VERO): a multicentre, double-blind, double-dummy, randomised controlled trial — Kendler DL et al., Lancet 2018. PMID: 29129436. View sourceStudy: RCT n=1360 (VERO)New vertebral fractures occurred in 5.4% on teriparatide vs 12.0% on risedronate (risk ratio 0.44).
5. [5] Molecular and cellular mechanisms of the anabolic effect of intermittent PTH — Jilka RL, Bone 2007. PMID: 17517365. View sourceStudy: reviewIntermittent PTH increases osteoblast number chiefly by delaying osteoblast apoptosis, explaining teriparatide's bone-forming action.