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FDA approved prescription peptideHuman trialsFDA approved

Abaloparatide

Abaloparatide

Last reviewed October 27, 2026 · 24 sources · Written for general readers · Compare with another compound →

The bottom line

Abaloparatide, sold as Tymlos, is an FDA approved drug that builds new bone in people with osteoporosis at high risk of fractures.[1] In a trial of about 1,600 women it cut new spine fractures from 4.2% to 0.6% over 18 months.[2] It can cause dizziness, a racing heart and high calcium, it caused bone cancer in rats, its label advises against more than two years of use in a lifetime, and there is no evidence it helps healthy people.[1]

Where the evidence stands

What it is

Abaloparatide is a lab made peptide of 34 amino acids. It is modeled on PTHrP, a natural protein related to parathyroid hormone, with a few changes, including one unusual building block called Aib near the end.[1][3]

It is FDA approved as Tymlos, an injection under the skin. It is approved for women after menopause and for men with osteoporosis who are at high risk of breaking a bone, or who could not use or did not respond to other osteoporosis drugs.[1]

Its FDA label groups it with parathyroid hormone analogs such as teriparatide, a similar bone building drug based on parathyroid hormone itself.[19]

Online, it is sometimes promoted outside medical care for faster healing and general wellness. The claims section below checks these against the evidence.

Name
Abaloparatide (Abaloparatide)
Other names
Tymlos, abaloparatide acetate
Type
FDA approved prescription peptide
Sequence
AVSEHQLLHDKGKSIQDLRRRELLEKLL-Aib-KLHTA-NH2
CAS number
247062-33-5
Formula
C174H300N56O49
Molecular weight
About 3961 g/mol (label value, in daltons)

What it does in the body

Abaloparatide is not made by the body. It is a lab made copy of part of PTHrP, a natural protein related to parathyroid hormone, the hormone that controls calcium.[1][3] It switches on the PTH1 receptor on bone cells, and when given as short daily pulses this tips the balance toward building bone rather than breaking it 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

Its label says it boosts osteoblasts, the cells that lay down new bone, on both the spongy inner bone and the hard outer shell.[1] In bone samples taken from the hip bone of 23 women after three months of daily shots, the share of bone surface that was actively forming new bone rose about 5 times in the spongy bone and about 13 times on the outer surface.[4] In blood, a marker of bone building rose to about 140% above starting levels by week 6, while a marker of bone breakdown rose less and later fell back toward placebo levels.[5]

Bone strength and shape

Measured in people

In men in the ATOM trial, scans showed bone density rose in the hip socket and the upper thigh bone over 12 months, and estimated thigh bone strength rose, mostly from the spongy inner bone. On placebo these measures barely changed.[6] In men, bigger early rises in the bone building blood marker predicted bigger spine density gains a year later.[7]

Calcium and kidneys

Measured in people

Because it acts on the same receptor parathyroid hormone uses, it can raise calcium in the blood and in the urine, which can lead to kidney stones.[1] In the main women's trial, high blood calcium was found in 3.4% of women on abaloparatide versus 6.4% on teriparatide, a similar drug.[2]

Heart and blood vessels

Measured in people

It relaxes blood vessels for a short time. One hour after the first shot, heart rate rose about 7.9 beats per minute on abaloparatide versus 1.2 on placebo, and in healthy volunteers it settled within about four hours.[8] Blood pressure can drop on standing in the first hours, causing dizziness.[1] Serious heart problems were about 1% in every group of the main trial.[8]

Cell signaling

Lab finding

In cell tests, abaloparatide binds more selectively than the PTH fragment teriparatide to one shape of the PTH1 receptor, which gives a shorter burst of the inner cell signal called cAMP.[9] Researchers think this shorter signal may favor bone building with less calcium release, but that link is a theory.[9]

Bone tumors

Seen in animals

In a two year rat study, it caused osteosarcoma, a bone cancer, in up to 87% of male and 62% of female rats at the highest dose.[1] Rats are very sensitive to this drug family, and whether this applies to people is not known.[1]

How it works

Bone is constantly broken down and rebuilt. Most osteoporosis drugs slow the breakdown. Abaloparatide instead speeds up the building.

  • It activates the PTH1 receptor on bone cells, which turns on a signaling chain inside the cell.[1]
  • This boosts osteoblasts, the cells that lay down new bone, on both the spongy inner bone and the hard outer shell.[1]
  • In the Japanese ACTIVE-J trial, a blood marker of bone building rose to about 140% above starting levels by week 6, while a marker of bone breakdown rose less and later fell back to placebo levels.[5]
  • Compared with the PTH fragment teriparatide, it favors a receptor shape that gives a shorter signal inside the cell, which may explain some differences in calcium effects.[9]

The bone building mechanism is well established and described on the FDA approved label. The receptor shape idea comes from lab work.

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

Bone building in monkeys, rats and mice, bone cancer in rats

  • In a two year study in rats, abaloparatide caused a strong, dose related rise in osteosarcoma, a bone cancer, and benign bone tumors in both males and females.[1]
  • At the highest dose, 87% of male rats and 62% of female rats developed osteosarcoma, versus 0 to 2% of untreated rats. Drug levels were 4 to 28 times those in people.[1]
  • In 80 monkeys, 65 of them with bone loss after removal of the ovaries, 16 months of daily shots raised spine bone density from month 4 and made spine bone stronger at the higher doses, without raising blood calcium or making outer bone more porous.[20]
  • In male rats whose testes were removed to cause bone loss, eight weeks of shots raised bone density and partly or fully reversed the loss, and made outer leg bone thicker, without more bone removing cells. There were 10 rats per group.[21]
  • In 120 mice with bone injuries, abaloparatide improved healing about as well as teriparatide, and the authors estimated it was about 2.5 times as potent by weight.[17]

Limit: Rats are very sensitive to this drug family, and whether the bone cancer risk applies to people is unknown.

Human studies

Large trials proved fewer fractures in women

  • ACTIVE trial: 2,463 women past menopause with osteoporosis (average age 69) got daily shots of abaloparatide, placebo or open label teriparatide for 18 months. New spine fractures occurred in 0.6% on abaloparatide versus 4.2% on placebo, an 86% lower risk.[1][2]
  • In the same trial, fractures outside the spine occurred in 2.7% on abaloparatide versus 4.7% on placebo, and high blood calcium occurred in 3.4% on abaloparatide versus 6.4% on teriparatide.[1][2]
  • ACTIVExtend: 1,139 women from ACTIVE then took alendronate, a bone pill, for two years. Over 43 months in total, spine fractures occurred in 0.9% of those who had started on abaloparatide versus 5.6% of those who started on placebo. Side effects were similar.[12]
  • ACTIVE-J: in a 78 week placebo controlled trial in Japanese women and men, spine bone density rose 12.5% more than placebo. Three people on placebo and none on abaloparatide had new spine fractures.[5]
  • ATOM trial: 228 men (average age 68) were randomly given daily shots of abaloparatide or placebo for 12 months. Spine density rose 8.5% versus 1.2%. Injection site reactions, dizziness, colds, joint pain, bronchitis, high blood pressure and headache each affected at least 5% of men.[10]
  • Bone samples from 23 women after three months of shots, in a study with no comparison group, showed the share of actively forming bone surface rose about 3 to 13 times depending on the bone surface.[4]
  • Heart rate: one hour after the first shot, heart rate rose about 7.9 beats per minute on abaloparatide, 5.3 on teriparatide and 1.2 on placebo. In healthy volunteers it settled within 4 hours, and serious heart problems were about 1% in every group.[8]
  • Patch trial: in 511 women, a skin patch version raised spine bone density 7.1% versus 10.9% with shots over 12 months and failed its main goal.[18]
  • Real world records: among 21,676 matched women on each drug, hip fractures over 18 months were 1.1% on abaloparatide versus 1.4% on teriparatide, and heart events were similar. The study was observational and funded by the maker.[15]
  • In women, the most common side effects were extra calcium in the urine, dizziness, nausea, headache and a pounding or racing heartbeat (5% versus under 1% on placebo).[1]

Limit: Strong fracture evidence exists for women, but the men's trial only measured bone density, head to head comparisons with teriparatide were not blinded, and no study has looked beyond two years of use.

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 78 week placebo controlled trial in Japan, spine bone density rose 12.5% more than on placebo and hip density 4.3% more.[5] In a 12 month trial of 228 men, spine density rose 8.5% versus 1.2% on placebo.[10] In the large ACTIVE trial of women, bone density gains were greater than on placebo at every site measured.[2] By 18 months, 44.5% of women on abaloparatide had gained more than 3% at the spine, hip and thigh neck together, versus 32.0% on teriparatide and 1.9% on placebo.[11]

Prevents broken bones

Shown in people

In the ACTIVE trial, about 1,600 women past menopause used abaloparatide or placebo for 18 months. New spine fractures fell from 4.2% to 0.6%, and fractures elsewhere from 4.7% to 2.7%.[1][2] When both groups then took alendronate for two more years, spine fractures over the whole 43 months were 0.9% versus 5.6%.[12] A review for the American College of Physicians found it lowers spine fractures, though more people quit because of side effects than on placebo.[13] The men's trial measured bone density only, not fractures.[10]

Raises bone density in men

Shown in people

In the ATOM trial, 228 men with osteoporosis were randomly given daily shots of abaloparatide or placebo for 12 months. Spine density rose 8.5% versus 1.2%, hip 2.1% versus 0.0%, and thigh neck 3.0% versus 0.2%.[10] At 12 months, 31.9% of men on the drug gained more than 3% at all three sites versus 1.5% on placebo.[14] Fractures were not measured.[10]

Works better than teriparatide

Mixed results

In ACTIVE, high blood calcium was less common on abaloparatide than on teriparatide, 3.4% versus 6.4%, and more women passed set bone density gains, but teriparatide was given open label, so people knew which drug they got.[2][11] Heart rate rose more after the first shot, about 7.9 beats per minute versus 5.3.[8] In insurance records of 21,676 matched women per drug, hip fractures over 18 months were 1.1% versus 1.4%, but this was a company funded look back study, not a randomized trial.[15] A 2025 pooled analysis of 17 studies, several of them observational, also favored abaloparatide for fractures outside the spine and hip fractures.[16]

Speeds healing of broken bones

Only in animals

In mice with a drilled bone hole or a cut thigh bone, both abaloparatide and teriparatide improved healing compared with saltwater shots. Callus density, a measure of new bone at the break, was 47% with abaloparatide, 38% with teriparatide and 23% in controls.[17] We found no controlled human trial of fracture healing.

A skin patch works as well as shots

No benefit in trials so far

In a 12 month trial of 511 women, a daily patch raised spine bone density 7.1% versus 10.9% for shots, so it failed to prove it was as good. Skin reactions at the patch site occurred in 94% of patch users versus 71% at shot sites.[18]

Anti aging or wellness for healthy people

Not tested

Every trial we found enrolled people with osteoporosis at high fracture risk.[2][10] We found no study testing it in healthy people for aging or wellness, and its label advises against more than two years of use in a lifetime.[1]

Known risks and side effects

  • Bone cancer in rats. Osteosarcoma rose sharply in rats, so the label says to avoid it in people at higher risk, such as those with Paget's disease, past bone radiation or bone cancer, and children with growing bones.[1]
  • Dizziness and racing heart. Blood pressure can drop when standing within about four hours of a shot, causing dizziness, a fast heartbeat or nausea. A pounding or racing heartbeat affected about 5% of women in the main trial, and dizziness was among the most common complaints in men.[1][10]
  • High calcium and kidney stones. It can raise blood calcium and urine calcium, which may lead to kidney stones. High blood calcium occurred in 3.4% of women in ACTIVE.[1][2]
  • Allergic reactions. Serious allergic reactions, including swelling of the face and throat, have been reported.[1]
  • Two year lifetime limit. Safety has not been studied beyond two years, and lifetime use longer than that is not recommended. Product bought outside a pharmacy has none of the label's quality controls.[1]

Regulatory status

Today: Abaloparatide is FDA approved as Tymlos for osteoporosis in women after menopause and in men at high fracture risk. The original boxed warning about bone cancer is no longer on the label, but osteosarcoma remains a listed warning.[1][19] It is not named on the 2026 World Anti Doping Agency list now in force or on the 2027 list that takes effect January 1, 2027.[22][23]

  1. FDA approved Tymlos for women after menopause, with a boxed warning about osteosarcoma seen in rats.[19][24]
  2. FDA approved a new indication for men with osteoporosis.[24]
  3. Results showed a skin patch version did not match the shots for raising spine bone density.[18]
  4. FDA approved the latest label update.[1][24]

Sources

  1. Radius Health. Tymlos (abaloparatide) injection prescribing information. U.S. Food and Drug Administration. Revised August 2026. FDA label 2026
  2. Miller PD, Hattersley G, Riis BJ, Williams GC, Lau E, Russo LA, et al; ACTIVE Study Investigators. 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
  3. U.S. Food and Drug Administration and NCATS. Global Substance Registration System: abaloparatide (UNII AVK0I6HY2U), codes. FDA GSRS
  4. Dempster DW, Zhou H, Rao SD, Recknor C, Miller PD, Leder BZ, Annett M, Ominsky MS, Mitlak BH. Early Effects of Abaloparatide on Bone Formation and Resorption Indices in Postmenopausal Women With Osteoporosis. J Bone Miner Res. 2021;36(4):644-653. PMID 33434314
  5. Matsumoto T, Sone T, Soen S, Tanaka S, Yamashita A, Inoue T. Abaloparatide Increases Lumbar Spine and Hip BMD in Japanese Patients With Osteoporosis: The Phase 3 ACTIVE-J Study. J Clin Endocrinol Metab. 2022;107(10):e4222-e4231. PMID 35977548
  6. Deal C, et al. The effects of abaloparatide on acetabular bone mineral density and proximal femur strength in men with osteoporosis. J Clin Densitom. 2026;29(2):101686. PMID 41812602
  7. Eastell R, et al. Bone turnover markers predict changes in bone mineral density in men treated with abaloparatide: results from the ATOM study. J Bone Miner Res. 2025;40(3):315-322. PMID 39791502
  8. Cosman F, Peterson LR, Towler DA, Mitlak B, Wang Y, Cummings SR. Cardiovascular Safety of Abaloparatide in Postmenopausal Women With Osteoporosis: Analysis From the ACTIVE Phase 3 Trial. J Clin Endocrinol Metab. 2020;105(11):3384-3395. PMID 32658264
  9. Hattersley G, Dean T, Corbin BA, Bahar H, Gardella TJ. Binding Selectivity of Abaloparatide for PTH-Type-1-Receptor Conformations and Effects on Downstream Signaling. Endocrinology. 2016;157(1):141-149. PMID 26562265
  10. Czerwinski E, et al. The Efficacy and Safety of Abaloparatide-SC in Men With Osteoporosis: A Randomized Clinical Trial. J Bone Miner Res. 2022;37(12):2435-2442. PMID 36190391
  11. Miller PD, Hattersley G, Lau E, Fitzpatrick LA, Harris AG, Williams GC, Hu MY, Riis BJ, Russo L, Christiansen C. Bone mineral density response rates are greater in patients treated with abaloparatide compared with those treated with placebo or teriparatide: Results from the ACTIVE phase 3 trial. Bone. 2019;120:137-140. PMID 30359763
  12. Bone HG, Cosman F, Miller PD, Williams GC, Hattersley G, Hu MY, et al. ACTIVExtend: 24 Months of Alendronate After 18 Months of Abaloparatide or Placebo for Postmenopausal Osteoporosis. J Clin Endocrinol Metab. 2018;103(8):2949-2957. PMID 29800372
  13. Ayers C, Kansagara D, Lazur B, Fu R, Kwon A, Harrod C. Effectiveness and Safety of Treatments to Prevent Fractures in People With Low Bone Mass or Primary Osteoporosis: A Living Systematic Review and Network Meta-analysis for the American College of Physicians. Ann Intern Med. 2023;176(2):182-195. PMID 36592455
  14. Dhaliwal R, et al. Response rates for lumbar spine, total hip, and femoral neck bone mineral density in men treated with abaloparatide: results from the ATOM study. JBMR Plus. 2024;8(2):ziae009. PMID 38505522
  15. Tabatabai L, Cosman F, Curtis JR, DeSapri KT, LaBaume CT, Reginster JY, Rizzoli R, Cortet B, Wang Y, Chiodo J 3rd, Mitlak BH. Comparative Effectiveness of Abaloparatide and Teriparatide in Women 50 Years of Age and Older: Update of a Real-World Retrospective Analysis. Endocr Pract. 2025;31(2):159-168. PMID 39551187
  16. Beaudart C, Veronese N, Douxfils J, Thiyagarajan JA, Bolzetta F, Albanese P, et al. PTH1 receptor agonists for fracture risk: a systematic review and network meta-analysis. Osteoporos Int. 2025;36(6):951-967. PMID 40047881
  17. Bernhardsson M, Aspenberg P. Abaloparatide versus teriparatide: a head to head comparison of effects on fracture healing in mouse models. Acta Orthop. 2018;89(6):674-677. DOI 10.1080/17453674.2018.1523771
  18. Lewiecki EM, Czerwinski E, Recknor C, Strzelecka A, Valenzuela G, Lawrence M, et al. Efficacy and Safety of Transdermal Abaloparatide in Postmenopausal Women with Osteoporosis: A Randomized Study. J Bone Miner Res. 2023;38(10):1404-1414. PMID 37417725
  19. Radius Health. Tymlos (abaloparatide) injection prescribing information, original approval. U.S. Food and Drug Administration. April 2017. FDA label 2017
  20. Doyle N, Varela A, Haile S, Guldberg R, Kostenuik PJ, Ominsky MS, Smith SY, Hattersley G. Abaloparatide, a novel PTH receptor agonist, increased bone mass and strength in ovariectomized cynomolgus monkeys by increasing bone formation without increasing bone resorption. Osteoporos Int. 2018;29(3):685-697. DOI 10.1007/s00198-017-4323-6
  21. Chandler H, Lanske B, Varela A, Guillot M, Boyer M, Brown J, et al. Abaloparatide, a novel osteoanabolic PTHrP analog, increases cortical and trabecular bone mass and architecture in orchiectomized rats by increasing bone formation without increasing bone resorption. Bone. 2019;120:148-155. PMID 30343166
  22. World Anti-Doping Agency. World Anti-Doping Code International Standard: Prohibited List 2026. Effective 1 January 2026. WADA 2026 List
  23. World Anti-Doping Agency. World Anti-Doping Code International Standard: The 2027 Prohibited List. In force 1 January 2027. WADA 2027 List
  24. U.S. Food and Drug Administration. Drugs@FDA: Tymlos (abaloparatide), NDA 208743, approval history. Drugs@FDA
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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