Teriparatide: what the evidence shows

What the human research shows

A model of what an evidence-graded page looks like when the evidence is good: large randomised trials, hard endpoints, a head-to-head against the standard drug, and decades of use. Included because it is one of the most-searched peptide medicines in the world.

Evidence profile0–5

Metabolic & weight—0.0
Cardiovascular—0.0
Muscle & growth—0.0
Healing & repair—0.0
Neuro & sleep—0.0
Immune & inflammation—0.0
Sexual & hormonal—0.0
Skin & appearance—0.0
Ageing & longevity—0.0

No benefit outcome for Teriparatide has both human evidence and a measurable effect, so the profile is empty. That is the finding, not a gap in the chart.

Outcome	Grade	Effect size	Human studies	Where the evidence comes from
Vertebral fracture risk (postmenopausal osteoporosis)	AEstablished	Large	1 large RCT (n=1,637, median 21 mo)	New spinal fractures in 14% on placebo against 5% and 4% on the two teriparatide doses — a relative risk of about 0.35. The trial was stopped early, on a rat osteosarcoma signal rather than efficacy, and still showed this.1
Non-vertebral fracture risk	AEstablished	Moderate	Same RCT	Non-spinal fragility fractures fell from 6% to 3% — relative risk about 0.47. Hip fractures specifically were too few to analyse in this trial.1
Bone mineral density	AEstablished	Large	Same RCT + many	Spine density rose 9–13 percentage points more than placebo, femoral neck 3–6 — the largest gains of any osteoporosis drug — with a small loss at the wrist shaft.1
Versus risedronate (head-to-head)	AEstablished	Moderate	VERO RCT (n=1,360, 24 mo)	In a direct comparison against a standard bisphosphonate in women with severe osteoporosis, teriparatide produced fewer new vertebral fractures. The result that moved it from second-line to first-line for the highest-risk patients in many guidelines.2
Adverse effectsadverse	AEstablished	Small	Approval trial + 20 years of surveillance	Nausea, headache, leg cramps, transient high calcium. The rat osteosarcoma finding that limited use to two years was never seen at excess in people; the FDA removed the limit and the boxed warning in 2020.1 3

AMultiple good human trials, consistentBSome human trials, mostly consistentCFew or weak human studiesDAnimal or anecdotal onlyeffect size · red = adverse

Literature searched to 10 September 2026. Human studies only; animal and cell work informs the mechanism section and nothing else.

Registered trials

ClinicalTrials.gov lists 137 interventional studies naming Teriparatide as an intervention — 97 completed, 4 recruiting, and 53 with results posted to the registry.

A registration is not a result. Anyone can register a study, and many never report — so this list shows what has been attempted, not what has been shown. The graded evidence above is the answer to whether something works.

Study	Phase	Status	Participants	Sponsor	Results
VERtebral Fracture Treatment Comparisons in Osteoporotic WomenNCT01709110 · started Oct 2012	Phase 4	Completed	1,366	Eli Lilly and Company	Posted
A Study That Will Compare the Effect of Two Drugs on Participants With Low Bone Mass and a Recent Hip FractureNCT00887354 · started Apr 2009	Phase 4	Completed	224	Eli Lilly and Company	Posted
Study of Teriparatide (FORTEO) to Treat Adults With Osteogenesis ImperfectaNCT00131469 · started Jun 2005	Phase 4	Completed	79	Oregon Health and Science University	Posted
Denosumab and Teriparatide Study (DATA-HD and DATA-EX)NCT02176382 · started Aug 2014	Phase 4	Completed	76	Massachusetts General Hospital	Posted
Effects of Teriparatide or Denosumab on Bone in Postmenopausal Women With OsteoporosisNCT01753856 · started Jan 2013	Phase 4	Completed	69	Eli Lilly and Company	Posted
Effects of Teriparatide or Zoledronic Acid Treatment on Bone in Postmenopausal Osteoporotic WomenNCT00927186 · started Jul 2009	Phase 4	Completed	69	Eli Lilly and Company	Posted
Novel Combination Therapy for Osteoporosis in MenNCT03994172 · started Jul 2019	Phase 4	Completed	40	VA Office of Research and Development	Posted
Bone Modeling Effects of Combined Anabolic/Antiresorptive AdministrationNCT04026256 · started Sept 2019	Phase 4	Completed	37	Massachusetts General Hospital	Posted

129 further studies are registered. Participant counts marked * are the sponsor's estimate, not a final enrolment. Source: ClinicalTrials.gov, read directly from the registry and refreshed weekly.

What it is

Teriparatide is the biologically active N-terminal fragment of parathyroid hormone, made by recombinant DNA and sold by Lilly as Forteo (US) and Forsteo (EU) since 2002–2003, now with biosimilars. It is the original anabolic osteoporosis drug: every other class slows bone resorption, this one drives new bone formation.

It is used for people at highest fracture risk — after a vertebral fracture, or where bisphosphonates have failed — typically for up to two years, followed by an antiresorptive drug to hold the gain.

How it is thought to work

The paradox is timing. Parathyroid hormone continuously elevated, as in hyperparathyroidism, dissolves bone. The same hormone in a short daily pulse activates osteoblasts more than osteoclasts, and bone is built. A once-daily injection produces the pulse; a longer-acting version would produce the disease.

What is still unknown

Whether courses longer than two years add benefit now that the limit is gone; the trials were shorter.
The best sequence with newer anabolics (romosozumab) and antiresorptives.

The molecule and how long it lasts

Identity

Formula: C181H291N55O51S2
Molecular weight: 4118 g/mol
CAS number: 52232-67-4
PubChem: CID 16133850

PubChem record, read 23 September 2026.

Pharmacokinetics

Route: Subcutaneous injection, once daily
Half-life: About 1 hour
Licensed regimen (Forteo): 20 mcg subcutaneously once daily

From the approved product's prescribing information: Forteo prescribing information (DailyMed) The regimen is the label's own wording, reproduced as a regulatory fact.

Regulatory status

European Union

Approved, prescription-only

Centrally authorised (Forsteo) since 2003; biosimilars since 2017.

United States

Approved, prescription-only

FDA-approved 2002 (Forteo). Two-year lifetime limit and osteosarcoma boxed warning removed in November 2020.

United Kingdom

Licensed, prescription-only

Licensed; NICE-recommended for specific high-risk groups.

Australia

Registered, prescription-only

On the ARTG; PBS-subsidised for severe osteoporosis.

Canada

Authorised, prescription-only

Health Canada-authorised.

Sport (WADA)

Not prohibited

Parathyroid hormone analogues are not on the Prohibited List.

Questions people actually ask

Is teriparatide a steroid?

No. It is a peptide hormone fragment — 34 amino acids of parathyroid hormone — with no anabolic-steroid activity. 'Anabolic' here means it builds bone.

Why was there a two-year limit?

Rats given lifelong high doses developed osteosarcoma. Twenty years of human use found no excess, and the FDA removed the limit and the boxed warning in 2020. Many prescribers still use two-year courses, followed by a drug that holds the gain.

Is it better than bisphosphonates?

For severe osteoporosis, the head-to-head VERO trial found fewer new spinal fractures with teriparatide than with risedronate. It is more expensive, injected daily, and usually followed by a bisphosphonate anyway.

One page per claimed effect

ADoes Teriparatide help with vertebral fracture risk?1 large RCT (n=1,637, median 21 mo)
ADoes Teriparatide help with non-vertebral fracture risk?Same RCT
ADoes Teriparatide help with bone mineral density?Same RCT + many
ADoes Teriparatide help with versus risedronate?VERO RCT (n=1,360, 24 mo)
AHow common is adverse effects with Teriparatide?Approval trial + 20 years of surveillance

References

1
Neer RM, Arnaud CD, Zanchetta JR, et al. Effect of parathyroid hormone (1-34) on fractures and bone mineral density in postmenopausal women with osteoporosis.N Engl J Med, 2001Fracture Prevention Trial; 1,637 women; the approval trial.
2
Kendler DL, Marin F, Zerbini CAF, et al. 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.Lancet, 2018Head-to-head; 1,360 women; 24 months.
3
Teriparatide (Forteo) prescribing information — 2020 label update removing the two-year limit and boxed warning.FDARegulatory status.

Change log

2026-09-10Initial publication. Grade A on the Fracture Prevention Trial and VERO.