Teriparatide is a lab-made copy of the first 34 amino acids of human parathyroid hormone, sold as Forteo, Bonsity and as generic teriparatide injection.[1] The FDA first approved it in 2002, and it is a daily bone-building shot for osteoporosis in people at high risk of breaking a bone.[2][1] In its main trial, it cut new spine fractures from 14% to 5% compared with placebo.[3]
What is teriparatide?
Most osteoporosis drugs, such as alendronate, slow the breakdown of bone. Teriparatide works the other way: once-daily doses stimulate bone-forming cells and build new bone.[1] It binds the same receptors as natural parathyroid hormone and is made in modified E. coli bacteria.[1]
Teriparatide is approved for three groups at high fracture risk, or who could not tolerate other treatment:[1]
- Postmenopausal women with osteoporosis
- Men with primary or low-testosterone (hypogonadal) osteoporosis
- Men and women with osteoporosis from long-term steroid (glucocorticoid) use of 5 mg prednisone a day or more
Teriparatide sits in our healing peptides category because it builds bone, but it is a prescription drug with large trials, unlike most peptides there.
What the research shows
- Fracture Prevention Trial (1,637 women): new spine fractures occurred in 5% on 20 mcg versus 14% on placebo; non-spine fragility fractures fell from 6% to 3%. Spine bone density rose 9 percentage points more than placebo.[3]
- Men (437 men): spine bone density rose 5.9% on 20 mcg after a median 11 months. The trial was stopped early because of the rat osteosarcoma finding.[4]
- Steroid users (428 patients): spine bone density rose 7.2% versus 3.4% with alendronate, and new spine fractures were 0.6% versus 6.1%.[5]
- VERO (1,360 women with severe osteoporosis): new spine fractures were 5.4% with teriparatide versus 12.0% with weekly risedronate, and clinical fractures were roughly halved. Non-spine fractures were lower but not significantly so.[6]
International research
In Japan, a once-weekly 56.5 mcg form was tested in the TOWER trial of 578 older adults; new spine fractures were 3.1% versus 14.5% on placebo.[7] This weekly form is not sold in the US. A Russian study of 100 adults aged 60 and older with severe osteoporosis and falls reported fewer new low-energy fractures, less chronic pain and higher bone density over 24 months of daily teriparatide, though it had no control group.[15]
Teriparatide dosage
| Forteo label | |
|---|---|
| Dose | 20 mcg injected under the skin once a day[1] |
| Where | Thigh or abdomen[1] |
| Pen | One pen holds 28 daily doses; discard 28 days after first use[1] |
| Storage | Keep refrigerated at 2 to 8°C at all times except when injecting[1] |
| First doses | Take where you can sit or lie down in case of dizziness[1] |
| Duration | Over 2 years in a lifetime only if fracture risk stays high[1] |
The label also suggests calcium and vitamin D if dietary intake is low.[1] Teriparatide comes ready to use in a prefilled pen, so no mixing is needed.
Teriparatide side effects
Events more common than placebo in the two main trials (Forteo label):[1]
| Side effect | Teriparatide | Placebo |
|---|---|---|
| Joint pain | 10.1% | 8.4% |
| Nausea | 8.5% | 6.7% |
| Dizziness | 8.0% | 5.4% |
| Leg cramps | 2.6% | 1.3% |
| Fainting (syncope) | 2.6% | 1.4% |
- High calcium: blood calcium peaks 4 to 6 hours after a dose. At least one high reading occurred in 11% of women and 6% of men, versus 2% and 0% on placebo.[1]
- Dizziness on standing: in healthy volunteers, 5% had brief orthostatic hypotension, usually within 4 hours of early doses.[1]
- Other warnings: allergic reactions, skin calcification (calciphylaxis), kidney stones and digoxin toxicity.[1]
The osteosarcoma warning and the 2020 label change
Rats given high doses for most of their lives developed osteosarcoma, a bone cancer, so Forteo launched with a boxed warning and a 2-year lifetime limit.[8][1] A 15-year US surveillance study interviewed 1,173 adults with osteosarcoma and found 3 prior teriparatide users, when about 4.2 were expected by chance.[9] In November 2020 the FDA removed the boxed warning and relaxed the 2-year limit.[2][8] The current label still says to avoid teriparatide in people at higher baseline risk, such as children with open growth plates, Paget’s disease or prior skeletal radiation.[1]
Teriparatide for fracture and tendon healing
Animal studies prompted interest in using teriparatide to speed fracture repair, but human results are mixed and this is off-label.
- Wrist fractures (102 women): the 40 mcg dose did not speed healing, which was the main goal. In a later analysis, 20 mcg shortened healing time (7.4 vs 9.1 weeks), but the authors urged caution.[12]
- 2026 meta-analysis: teriparatide did not delay healing and may shorten time to union, but the authors said more evidence is needed.[13]
- Rotator cuff repair (50 patients): 3 months of 20 mcg daily gave no better function or retear rate than placebo at 1 year.[14]
Teriparatide vs abaloparatide
Abaloparatide (Tymlos) is the other daily PTH1 receptor drug. In the ACTIVE trial, which included an open-label teriparatide group, high blood calcium occurred in 3.4% on abaloparatide versus 6.4% on teriparatide.[16] A meta-analysis of manufacturer-sponsored trials found slightly larger hip bone density gains with abaloparatide, but not enough fracture data to compare.[17]
Who should not use teriparatide
- People with a history of severe allergy to teriparatide.[1]
- People with high blood calcium or a disorder that raises it, such as primary hyperparathyroidism.[1]
- Children and young adults with open growth plates, and people with Paget’s disease, bone cancer or bone metastases, or prior radiation to the skeleton.[1]
- People taking digoxin should be monitored, since a rise in calcium can raise the risk of digoxin toxicity.[1]
Generics and cost
Bonsity was approved in 2019 through a separate application, and generic teriparatide injection followed, including an Amphastar version approved in December 2025.[10][11] All carry the same 20 mcg daily dose and indications. Prices vary by product and insurance.
Is teriparatide legal?
Yes, by prescription. It is FDA-approved for osteoporosis, and products sold online as research chemicals are not FDA-approved teriparatide.[1]
