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Prescription peptide hormoneHuman trialsFDA approved

Teriparatide

Teriparatide (recombinant human parathyroid hormone 1-34)

Last reviewed October 27, 2026 · 23 sources · Written for general readers · Compare with another compound →

The bottom line

Teriparatide is an FDA approved prescription drug that builds new bone in people with osteoporosis at high fracture risk. In large trials it cut new spine fractures by about two thirds versus placebo and by more than half versus a standard osteoporosis pill. Rats given it for most of their lives developed bone cancer, but large human safety studies have not shown higher bone cancer risk, so FDA removed the boxed warning in 2020. The one trial of tendon repair found no benefit, and claims for joints or sports injuries are untested.

Where the evidence stands

What it is

Teriparatide is a lab made copy of the first 34 amino acids of human parathyroid hormone (PTH), the active part of the full 84 amino acid hormone. It is made in E. coli bacteria using recombinant DNA.[1]

The FDA label lists its formula as C181H291N55O51S2 and its weight as about 4117.8 daltons.[1]

Forteo was first approved in the United States in November 2002.[2] Another teriparatide product, Bonsity, was approved in October 2019.[3]

It is approved for postmenopausal women with osteoporosis at high fracture risk, men with primary or low testosterone related osteoporosis, and men and women with osteoporosis caused by steroid medicines.[1]

Name
Teriparatide (Teriparatide (recombinant human parathyroid hormone 1-34))
Other names
Forteo, Bonsity, rhPTH(1-34)
Type
Prescription peptide hormone
Formula
C181H291N55O51S2
Molecular weight
About 4117.8 g/mol

What it does in the body

Natural parathyroid hormone controls how bone and kidneys handle calcium and phosphate. Teriparatide copies its active end and acts on the same receptors. Given in short daily bursts, it builds bone, while constant high PTH breaks bone down.[1]

This is the biology, area by area. A change measured in the body, like a higher blood level, does not always mean a person feels a benefit. The claims check below covers that.

Bones

Well established

Daily shots under the skin push bone building cells (osteoblasts) to work harder than bone removing cells (osteoclasts), adding bone on both the inner spongy bone and the hard outer shell.[1] In 1,637 postmenopausal women, spine bone density rose about 9.7% with teriparatide versus 1.1% with placebo over a median of 19 months.[1][4]

Bone renewal markers

Measured in people

Blood markers of new bone formation rose first, by about 41 to 45% in women and 23% in men, and markers of bone breakdown rose later.[1] This shows bone renewal speeds up, with building leading the way.

Blood calcium

Well established

After each shot, blood calcium starts rising within about 2 hours, peaks at 4 to 6 hours and returns to baseline by 16 to 24 hours. Brief high calcium readings occurred in 11% of women versus 2% on placebo.[1] In a 2,463 woman trial, high calcium occurred in 6.4% on teriparatide versus 3.4% on the related drug abaloparatide.[5]

Kidneys and minerals

Well established

Like natural PTH, it makes the kidneys release more phosphate, so blood phosphate dips briefly. Calcium in the urine rose slightly in women. Uric acid rose above normal in about 3% of users versus 1% on placebo, without more gout or kidney stones.[1]

Blood pressure

Measured in people

A brief drop in blood pressure on standing up occurred in about 5% of volunteers, mostly with the first few shots. In the main trials, dizziness affected 8.0% versus 5.4% on placebo.[1]

Jaw bone

Measured in people

In 40 adults having gum surgery, six weeks of shots led to more new bone around the teeth at one year than placebo (about 29% versus 3% bone gain).[6]

Bone cancer risk

Seen in animals

In rats given it for most of their lives, bone mass rose greatly and osteosarcoma, a bone cancer, appeared at every exposure level.[7] In people, a 15 year US cancer registry study found 3 osteosarcoma cases with past teriparatide use against about 4 expected by chance, so no increase was seen.[8]

How it works

Teriparatide copies the active end of the body's own parathyroid hormone.[1]

  • Given as a daily shot under the skin, it raises bone mass and bone density, as shown in both rat studies and human trials.[7][4]
  • Short daily bursts favor bone building, while continuous high PTH, as in overactive parathyroid glands, can harm the skeleton.[1]
  • It briefly raises blood calcium after each use, which explains some of its warnings.[1]

The bone building effect is well proven in people. Researchers think the rat tumors came from very long treatment and an exaggerated bone response that is specific to rats.[7]

What the research shows

We keep animal and human evidence apart. A result in animals is a reason to study something in people, not proof that it works in people.

Animal and lab studies

Rats developed bone cancer

  • In a two year rat study, teriparatide greatly increased bone mass and filled in much of the marrow space.[7]
  • Osteosarcoma (a bone cancer) appeared in every treated group, and more often with higher exposure and longer treatment.[1][7]
  • The study authors argued the rat findings likely do not predict cancer risk in adults with mature skeletons treated for a limited time.[7]

Limit: Rats were treated for most of their lifespan with a skeleton that keeps growing, which is very different from how people use the drug.

Human studies

Large controlled trials show fewer fractures

  • Postmenopausal women: a placebo controlled trial of 1,637 women with past spine fractures, treated for a median of 19 months, found new spine fractures in about 14% on placebo versus 5% on daily teriparatide shots, a 65% relative drop.[2][4][1]
  • The same trial showed fewer fractures outside the spine (about 5.5% versus 2.6%) and higher bone density in the spine (9.7% versus 1.1%) and hip (2.6% versus a 1.0% loss).[1][4]
  • Men: in 437 men with osteoporosis followed for a median of 10 months, spine bone density rose about 5.9% with teriparatide versus 0.5% with placebo. The hip change was small and not clearly different.[1]
  • Steroid users: in an 18 month double blind trial of 428 adults taking steroid medicines, teriparatide raised spine density more than alendronate, a common osteoporosis pill (7.2% versus 3.4%), and new spine fractures were 0.6% versus 6.1%. More people on teriparatide had high blood calcium readings.[9]
  • Severe osteoporosis: the VERO trial gave 1,360 women either teriparatide shots or risedronate pills for two years, each with a dummy version of the other. New spine fractures were 5.4% versus 12.0%, and fractures causing symptoms were 4.8% versus 9.8%. Fractures outside the spine (4.0% versus 6.1%) were not clearly different. The maker funded the trial.[10]
  • Hip fractures: a 2019 analysis of 23 randomized trials with 8,644 people, mostly comparing teriparatide with other osteoporosis drugs, found about 56% lower odds of hip fracture with teriparatide. Only 34 hip fractures occurred in total, and arm and wrist fractures did not clearly change.[11]
  • Against bisphosphonate pills: a 2024 analysis of 23 head to head trials with 6,680 people, comparing teriparatide or denosumab with bisphosphonate pills, found about 39% fewer fractures with teriparatide, with no increase in side effects.[12] A 2025 network analysis found the related drug abaloparatide did somewhat better than teriparatide for hip and other fractures outside the spine.[19]
  • Switching drugs: in the DATA-Switch study, 77 women who had used teriparatide, denosumab or both for two years were switched for two more years. Teriparatide followed by denosumab gave the largest spine gain (about 18%), while denosumab followed by teriparatide led to smaller hip gains and some bone loss.[18]
  • Against abaloparatide: in the ACTIVE trial of 2,463 women, 818 took open label teriparatide shots. High blood calcium occurred in 6.4% of them versus 3.4% on abaloparatide.[5]
  • Brittle bone disease: in the 2026 TOPaZ trial, 350 adults with osteogenesis imperfecta were assigned to two years of teriparatide shots followed by a bone drip, or to standard care. Bone density rose more, but new fractures were the same (about 37% in each group).[13]
  • Wrist fractures: in a double blind trial of 102 women, eight weeks of shots did not meet its main goal of faster healing. The lower amount healed somewhat faster than placebo in a secondary comparison.[14]
  • Pelvic fractures: in a placebo controlled trial of 35 adults with an average age of 82, healing at three months was similar (50% versus 53%), and pain fell equally, though walking and balance tests improved more with teriparatide.[15]
  • Hip fracture surgery: in a 2025 double blind trial of 50 patients, 12 weeks of shots after hip fracture fixation made bone union on x rays come about three weeks sooner than placebo, but function and walking tests did not differ.[16]
  • Shoulder tendon repair: in a 2025 triple blind trial, 50 adults having rotator cuff repair got three months of teriparatide or placebo shots. At one year, shoulder scores, range of motion, pain and retear rates were no different.[17]
  • Gum disease: in 40 adults having gum surgery, six weeks of shots gave more jaw bone regrowth at one year than placebo (29% versus 3%), with no serious side effects.[6]
  • Bone cancer safety: two large U.S. insurance database studies found 3 osteosarcoma cases among 379,283 Forteo users and none among 153,316 users, which the label says suggests a risk similar to people not taking it.[20][1] A separate 15 year cancer registry study found 3 cases with past teriparatide use against 4.17 expected, a ratio of 0.72.[8]

Limit: Fracture prevention is well proven. Healing and dental trials are small, and the cancer safety studies are observational and cannot rule out a very small risk.

Claims check

The most common claims about this compound, and what studies actually found. Verdicts rate the evidence, not whether you should use it.

Builds bone density

Shown in people

In a placebo controlled trial of 1,637 postmenopausal women, spine bone density rose about 9.7% with teriparatide versus 1.1% with placebo.[1][4] In 437 men, spine density rose about 5.9% versus 0.5% over a median of 10 months.[1] In 428 people on steroid medicines, it raised spine density 7.2% versus 3.4% with alendronate.[9]

Prevents broken bones

Shown in people

New spine fractures fell from about 14% with placebo to 5% with teriparatide in 1,637 women.[1][4] In 1,360 women with severe osteoporosis, new spine fractures were 5.4% versus 12.0% with risedronate over two years.[10] In steroid users, new spine fractures were 0.6% versus 6.1% with alendronate.[9] A 2019 analysis of 23 trials with 8,644 people linked teriparatide with about 56% lower odds of hip fracture, though hip fractures were few, and found no clear effect on wrist or arm fractures.[11] A 2024 analysis of 23 head to head trials with 6,680 people, which compared teriparatide or denosumab with bisphosphonate pills, found about 39% fewer fractures with teriparatide than with the pills.[12] It did not cut fractures in a 2026 trial of 350 adults with brittle bone disease.[13]

Speeds healing of broken bones

Mixed results

In 102 women with wrist fractures, the trial's main test failed, though the lower of two amounts healed somewhat faster (about 7.4 versus 9.1 weeks) in a later comparison.[14] In 35 older adults with pelvic fractures, about half healed by three months with either teriparatide or placebo.[15] In a 2025 double blind trial of 50 people with hip fractures fixed by surgery, bone union on x rays came sooner (about 7.4 versus 10.6 weeks), but hip function and walking tests were no better.[16]

Regrows jaw bone around teeth

Mixed results

In one trial of 40 people with severe gum disease having surgery, six weeks of teriparatide shots led to about 29% bone gain at one year versus 3% with placebo.[6] This was small and has not become an approved use.[1]

Heals tendons, joints and sports injuries

No benefit in trials so far

The only trial we found tested tendons: in a 2025 triple blind trial of 50 adults having shoulder rotator cuff repair, three months of shots gave no better shoulder scores, motion or pain than placebo, and retears were similar (about 9% versus 10%).[17] Ligament, cartilage and muscle injuries have not been tested. The label says to avoid it in young people whose growth plates are still open.[1]

Bone gains last after stopping

Mixed results

In the DATA-Switch study of 77 women, spine density kept rising when teriparatide was followed by denosumab, reaching about 18% above baseline at four years. Going the other way, from denosumab to teriparatide, gave smaller hip gains (about 2.8% versus 6.6%) and some bone loss.[18] So results depend on what comes next.

Known risks and side effects

  • Bone cancer warning remains. The label still warns about osteosarcoma and says to avoid teriparatide in people at higher risk, such as young people with open growth plates, Paget's disease, bone cancer or past radiation to the bones. Data on bone cancer risk beyond two years of use are limited.[1]
  • Dizziness and fainting. In the main trials, dizziness occurred in 8.0% versus 5.4% on placebo and fainting in 2.6% versus 1.4%. Brief low blood pressure on standing occurred in about 5% of volunteers, mostly with the first few shots.[1]
  • High calcium and uric acid. Brief high blood calcium a few hours after a shot occurred in 11% of women (2% on placebo) and 6% of men. Uric acid rose above normal in about 3% versus 1%. Skin calcium deposits, including a serious condition called calciphylaxis, have been reported.[1][21]
  • Common side effects. Joint pain (10.1% versus 8.4% on placebo), nausea (8.5% versus 6.7%) and leg cramps (2.6% versus 1.3%) were more common than with placebo. Serious allergic reactions have also been reported.[1]
  • Drug interactions, kidney stones and switching. Higher calcium can make the heart drug digoxin more toxic, and people with active or recent kidney stones need extra caution.[1] Switching from denosumab to teriparatide was linked to bone loss at the hip in one study.[18]

Regulatory status

Today: Teriparatide is FDA approved for osteoporosis in people at high fracture risk, sold as Forteo and other versions. The boxed warning was removed in 2020, but osteosarcoma is still listed as a warning.[1][21] Parathyroid hormone is not named on the 2026 WADA Prohibited List or on the 2027 list that starts January 1, 2027.[22][23]

  1. FDA approved Forteo with a boxed warning about osteosarcoma seen in rats, telling doctors to use it only when the benefit clearly outweighs the risk.[2]
  2. FDA approved Bonsity, another teriparatide product.[3]
  3. FDA approved a label update that removed the osteosarcoma boxed warning, added human safety study results, allowed longer treatment for people who stay at high fracture risk, and added calciphylaxis to the calcium warning.[21]
  4. FDA approved the most recent Forteo label update, which still lists osteosarcoma under warnings.[1]

Sources

  1. Eli Lilly and Company. Forteo (teriparatide) injection prescribing information. U.S. Food and Drug Administration. 2026. FDA label 2026
  2. Eli Lilly and Company. Forteo (teriparatide) injection prescribing information, original approval. U.S. Food and Drug Administration. 2002. FDA label 2002
  3. U.S. Food and Drug Administration. Drugs@FDA: Bonsity (teriparatide), NDA 211939. Drugs@FDA
  4. Effect of parathyroid hormone (1-34) on fractures and bone mineral density in postmenopausal women with osteoporosis. N Engl J Med. 2001;344(19):1434-41. PMID 11346808
  5. Miller PD, Hattersley G, Riis BJ, Williams GC, et al. Effect of Abaloparatide vs Placebo on New Vertebral Fractures in Postmenopausal Women With Osteoporosis: A Randomized Clinical Trial. JAMA. 2016;316(7):722-733. PMID 27533157
  6. Bashutski JD, Eber RM, Kinney JS, Benavides E, Maitra S, Braun TM, et al. Teriparatide and osseous regeneration in the oral cavity. N Engl J Med. 2010;363(25):2396-2405. PMID 20950166
  7. Vahle JL, Sato M, Long GG, Young JK, Francis PC, Engelhardt JA, Westmore MS, Ma YL, Nold JB. Skeletal Changes in Rats Given Daily Subcutaneous Injections of Recombinant Human Parathyroid Hormone (1-34) for 2 Years and Relevance to Human Safety. Toxicol Pathol. 2002;30(3):312-321. Toxicol Pathol 2002
  8. Gilsenan A, Midkiff KD, Harris D, Kellier-Steele N, et al. Teriparatide Did Not Increase Adult Osteosarcoma Incidence in a 15-Year US Postmarketing Surveillance Study. J Bone Miner Res. 2021;36(2):244-251. PMID 32990990
  9. Saag KG, Shane E, Boonen S, Marín F, Donley DW, Taylor KA, et al. Teriparatide or alendronate in glucocorticoid-induced osteoporosis. N Engl J Med. 2007;357(20):2028-2039. PMID 18003959
  10. Kendler DL, Marin F, Zerbini CAF, Russo LA, Greenspan SL, Zikan V, 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. 2018;391(10117):230-240. PMID 29129436
  11. Díez-Pérez A, Marin F, Eriksen EF, Kendler DL, et al. Effects of teriparatide on hip and upper limb fractures in patients with osteoporosis: A systematic review and meta-analysis. Bone. 2019;120:1-8. PMID 30268814
  12. Li M, Ge Z, Zhang B, Sun L, et al. Efficacy and safety of teriparatide vs. bisphosphonates and denosumab vs. bisphosphonates in osteoporosis not previously treated with bisphosphonates: a systematic review and meta-analysis of randomized controlled trials. Arch Osteoporos. 2024;19(1):89. PMID 39312040
  13. Hald JD, et al.; TOPaZ Investigators. Teriparatide Plus Zoledronic Acid for Osteogenesis Imperfecta: A Randomized Clinical Trial. JAMA. 2026;336(2):116-124. PMID 42133304
  14. Aspenberg P, Genant HK, Johansson T, Nino AJ, See K, Krohn K, et al. Teriparatide for acceleration of fracture repair in humans: a prospective, randomized, double-blind study of 102 postmenopausal women with distal radial fractures. J Bone Miner Res. 2010;25(2):404-414. PMID 19594305
  15. Nieves JW, Cosman F, McMahon D, Redko M, Hentschel I, Bartolotta R, et al. Teriparatide and pelvic fracture healing: a phase 2 randomized controlled trial. Osteoporos Int. 2022;33(1):239-250. PMID 34383100
  16. Tanavalee C, Ngarmukos S, Amarase C, Tantavisut S, et al. A randomized controlled trial of teriparatide for accelerating bone union and improving clinical outcomes in patients with pertrochanteric fracture fixation. Sci Rep. 2025;15(1):19465. PMID 40461584
  17. Guity MR, et al. Effectiveness of Teriparatide (rhPTH) in Enhancing Functional Recovery After Arthroscopic Rotator Cuff Repair: A Triple-Blind Randomized Clinical Trial. JB JS Open Access. 2025;10(3):e25.00035. PMID 40978001
  18. Leder BZ, Tsai JN, Uihlein AV, Wallace PM, et al. Denosumab and teriparatide transitions in postmenopausal osteoporosis (the DATA-Switch study): extension of a randomised controlled trial. Lancet. 2015;386(9999):1147-1155. PMID 26144908
  19. Beaudart C, Veronese N, Douxfils J, Thiyagarajan JA, et al. PTH1 receptor agonists for fracture risk: a systematic review and network meta-analysis. Osteoporos Int. 2025;36(6):951-967. PMID 40047881
  20. Eli Lilly and Company. Forteo (teriparatide) injection prescribing information, supplement 54. U.S. Food and Drug Administration. 2020. FDA label 2020
  21. U.S. Food and Drug Administration. Supplement approval letter, NDA 021318/S-054 (Forteo). November 2020. FDA letter
  22. World Anti-Doping Agency. The 2026 Prohibited List. WADA 2026
  23. World Anti-Doping Agency. The 2027 Prohibited List. In force January 1, 2027. WADA 2027
Medical disclaimer

This page is educational information only. It is not medical advice and does not replace care from a licensed medical provider. Do not use this page to decide whether to take any substance. Talk to a licensed medical provider first.

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