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Bone & mineral

Teriparatide

Also called Forteo, rhPTH(1-34), PTH 1-34, Bonsity, Parathar

Teriparatide is a lab-made copy of the first 34 amino acids of human parathyroid hormone. It is an FDA-approved daily injection for osteoporosis that builds new bone, unlike most osteoporosis drugs, which only slow bone loss.

FDA-approvedApproved by the FDA for at least one use after large human trials.

All printable flashcards

Drawn from its published sequence: 34 residues, one bead each.

Overview

Teriparatide is a lab-made copy of the first 34 amino acids of human parathyroid hormone. It is an FDA-approved daily injection for osteoporosis that builds new bone, unlike most osteoporosis drugs, which only slow bone loss.

How it works

Established: teriparatide activates the PTH1 receptor on bone-forming cells (osteoblasts). Given once a day in short pulses, this signal favors bone formation over bone breakdown, raising bone density and lowering fracture risk. Continuous high PTH levels (as in hyperparathyroidism) have the opposite effect, which is why the dosing pattern matters.

What research shows

  • Pivotal RCT in 1,637 postmenopausal women (median 19 months): new vertebral fractures 5.0% with 20 mcg/day vs 14.3% with placebo, a 65% relative reduction (FDA label).
  • Osteosarcoma surveillance programs (US case series, Nordic case series, a 75,247-patient registry linkage, Medicare and commercial-claims cohorts) found no increase over background rates (Krege et al., JBMR Plus 2022; authors employed by Lilly).
  • Also approved for men with primary or hypogonadal osteoporosis and for glucocorticoid-induced osteoporosis (FDA label).

Doses studied in people

Study or labelDose usedSource
FDA label (Forteo), all approved osteoporosis indications20 mcg subcutaneously once daily1

The label dose is 20 mcg once daily; using it for more than 2 years in a lifetime is advised only for patients who stay at high fracture risk.

Read this first: these are the amounts given to participants in published studies or written on official prescribing labels, reported for reference. They are not recommendations. Trial doses were chosen for specific patients under medical supervision, and a dose that is safe in one person can be harmful in another.

Weekly protocol

How the schedule looks week by week. Each chart says where it comes from: a prescribing label, a clinical trial, or a protocol commonly reported online.

Forteo label dosing

Prescribing label

One week

D1D2D3D4D5D6D7

Once daily · Subcutaneous injection

Dose by week

20 mcgwk 1+
Course
Up to 2 years in a lifetime, unless fracture risk stays high
Note
Use beyond 2 years should be considered only for patients who remain at, or return to, high fracture risk.
Source
FORTEO (teriparatide) injection prescribing information (FDA, 2026)

Reference only, not a recommendation. Label and trial schedules were set for specific patients under medical supervision. Use the calculator only to understand the arithmetic.

Safety

  • Osteosarcoma in rats; human studies show no increased risk, but data beyond 2 years are limited. Avoid in people at higher risk (open growth plates, Paget's disease, bone metastases, prior skeletal radiation) (FDA label).
  • Orthostatic hypotension: 5% of healthy volunteers, usually with the first doses; first doses should be given sitting or lying down (FDA label).
  • Transient rise in blood calcium; avoid in hypercalcemic disorders such as primary hyperparathyroidism; calciphylaxis has been reported; monitor patients on digoxin (FDA label).
  • Common adverse reactions vs placebo: arthralgia 10.1% vs 8.4%, nausea 8.5% vs 6.7%, dizziness 8.0% vs 5.4% (FDA label).
  • Hypersensitivity reactions, including anaphylaxis and angioedema (FDA label).

Report side effects of any drug or product to the FDA through MedWatch. For a possible poisoning in the US, call Poison Control at 1-800-222-1222.

Storage and stability

Pen kept refrigerated at 2-8°C at all times except during injection; do not freeze; discard 28 days after first use (FDA label).

General lab handling, not instructions for personal use. See Storage and stability.

History

Teriparatide acetate was first approved in the US in 1987 as a diagnostic agent (the label's 'initial approval' date). Eli Lilly's Forteo was approved in 2002 for osteoporosis. Its phase 3 trials stopped early when high-dose rat studies showed osteosarcoma, so the original label carried a boxed warning and a 2-year lifetime limit. After about 20 years of surveillance found no clear signal in people, the FDA removed the boxed warning in November 2020 and allowed use beyond 2 years for patients who stay at high fracture risk.

Common questions

Is teriparatide FDA-approved?

Yes. Forteo was approved in 2002 for osteoporosis in people at high fracture risk, including men and steroid-related bone loss 12.

Does teriparatide prevent fractures?

In a trial of 1,637 postmenopausal women, new spine fractures occurred in 5.0% on teriparatide vs 14.3% on placebo, a 65% relative reduction 1.

What dose is on the FDA label?

The label lists 20 mcg injected under the skin once daily 1. Use beyond 2 years in a lifetime is only for patients who remain at high fracture risk 1. This is label information, not advice.

Does teriparatide cause bone cancer?

High doses caused osteosarcoma in rats, but about 20 years of human surveillance found no increase above normal rates 2. The FDA removed the boxed warning in November 2020 2.

What are the common side effects?

Compared with placebo, joint pain affected 10.1% vs 8.4%, nausea 8.5% vs 6.7% and dizziness 8.0% vs 5.4% 1. Dizziness on standing can occur with first doses, so these are given sitting or lying down 1.

How is teriparatide stored?

The pen stays refrigerated at 2 to 8°C except during injection, must not be frozen, and is discarded 28 days after first use 1.

Related compounds

Bone & mineralFDA-approvedFlashcard

Abaloparatide

Tymlos · Eladynos

Abaloparatide is a lab-made peptide modeled on parathyroid hormone-related protein (PTHrP).

Bone & mineralFDA-approvedFlashcard

Calcitonin (salmon)

Miacalcin · salmon calcitonin

Salmon calcitonin is a thyroid-type hormone taken from salmon that lowers blood calcium and slows bone breakdown.

Sources

  1. FORTEO (teriparatide) injection prescribing information FDA label
  2. Teriparatide and Osteosarcoma Risk: History, Science, Elimination of Boxed Warning, and Other Label Updates (Krege et al., JBMR Plus 2022) PubMed review
  3. KEGG DRUG: Teriparatide (D06078) Journal
  4. WADA 2026 Prohibited List Regulatory

Last reviewed 2026-10-25 · How we research · Found an error? See our corrections policy.