Evidence memo / Bone & musculoskeletal

Teriparatide

Also: Forteo · Bonsity · PTH 1-34

Teriparatide (Forteo) is a recombinant fragment of parathyroid hormone (PTH 1-34) approved as a bone-building treatment for osteoporosis in people at high fracture risk, including postmenopausal women, men, and those on long-term glucocorticoids. It is given by daily injection. The Watchlist boundary is keeping it to its approved osteoporosis use and accurately noting that the earlier osteosarcoma boxed warning, based on rat studies, was later removed.

Approved for specific usesPost-market evidenceSafety / regulatory watch

The verdict

Our read at a glance.

Whether teriparatide's approved anabolic osteoporosis benefit is understood within that specific high-fracture-risk setting, rather than generalized.

The signal
Randomized trials show teriparatide builds bone density and reduces fractures in osteoporosis. Unlike antiresorptive drugs, it stimulates new bone formation, so it is used in higher-risk patients.
The unknown
How best to sequence it with antiresorptive drugs, since bone gains can be lost after stopping, and its long-term positioning against newer anabolic agents.
Our read
A proven bone-building osteoporosis drug for high-risk patients. Teriparatide clearly works for its approved use, and the once-feared osteosarcoma signal came from rats and led to a boxed warning that was later removed when human data did not bear it out.

The mechanism

How it works.

Teriparatide is a recombinant copy of the first 34 amino acids of parathyroid hormone, the active end of the molecule. It binds the PTH-1 receptor on bone-building osteoblasts, and because the daily injection delivers the hormone in a brief spike rather than the steady high levels that drive bone loss, that intermittent signal tips the balance toward bone formation. The result is new bone and greater density in people with osteoporosis.

Safety & regulatory boundary

The consequential part.

Teriparatide once carried a boxed warning for a possible osteosarcoma risk based on rat studies, along with a lifetime-use limit. The FDA later removed that boxed warning and the limit after human data did not show the expected risk. It remains a prescription osteoporosis drug for specific high-risk patients. Forteo and other teriparatide products are not the same as compounded or research-labeled teriparatide, and the approved use does not extend to general wellness or anti-aging claims.

What's next

What we're watching.

Sequencing strategies with antiresorptive drugs, long-term safety follow-up, and comparisons with newer anabolic agents.

Context

Why this is discussed.

Teriparatide was the first bone-building osteoporosis drug, a different approach from the more common drugs that slow bone loss.

The evidence base

23 cited references.

Regulatory & labels3

DailyMed label: teriparatide

Alvogen, Inc. (FDA label) · 2025

DailyMed label: Bonsity

Alvogen Inc. (FDA label) · 2025

DailyMed label: Teriparatide

BluePoint Laboratories (FDA label) · 2026

Registered trials8

Teriparatide (Forsteo) Treatment in Postmenopausal Women: Mechanism of Action

ClinicalTrials.gov · PHASE4 · COMPLETED · 2011-01

A Study of B-3E07 and Forsteo® in Healthy Adult Female Participants

ClinicalTrials.gov · PHASE1 · RECRUITING · 2026-04-10

Novel Precision Medicine Approach to Treatment of Osteoporosis Based on Bone Turnover

ClinicalTrials.gov · PHASE4 · ACTIVE_NOT_RECRUITING · 2022-03-21

Teriparatide (PTH) and Bone Strength in Postmenopausal Women

ClinicalTrials.gov · ACTIVE_NOT_RECRUITING · 2008-06

Effects of Teriparatide (PTH) on Bone in Men and Women With Osteoporosis

ClinicalTrials.gov · ACTIVE_NOT_RECRUITING · 2004-11

Indexed literature (PubMed)12

Interventions for managing medication-related osteonecrosis of the jaw

Beth-Tasdogan NH et al. · Cochrane Database Syst Rev · 2022

Keep reading

Related published memos.