Abaloparatide (Tymlos): Uses, Dosage and Side Effects
Abaloparatide (Tymlos): the FDA-approved osteoporosis peptide - label dosing, the ACTIVE trial results, and its osteosarcoma warning.
The short version
Abaloparatide (Tymlos) is an FDA-approved daily-injection peptide that builds new bone through the parathyroid hormone pathway, like teriparatide. Its main ACTIVE trial found fewer new spine fractures and higher bone density than placebo. Its label carries osteosarcoma warning language from rat studies and a 2-year lifetime-use limit, which, unlike teriparatide's, has not been removed.
- FDA-approved for osteoporosis in postmenopausal women, and to raise bone density in men, at high fracture risk.
- The ACTIVE trial found fewer new spine fractures and higher bone density than placebo.
- The label still advises against more than 2 years of use in a lifetime; unlike teriparatide's, this limit has not been removed.
- I could not verify Australian (TGA) approval for abaloparatide.
Abaloparatide at a glance
- What it is
- Synthetic parathyroid hormone-related protein (PTHrP) analogue, a peptide
- Main use
- FDA-approved to treat osteoporosis in postmenopausal women at high fracture risk, and to increase bone density in men with osteoporosis at high fracture risk, by stimulating new bone formation.
- Generic name
- abaloparatide
- Brand names
- Tymlos (Radius Health) Label
- Molecular formula
- C174H300N56O49 (3961 g/mol) Structure
- Evidence
- Strong human evidence
- US status
- FDA-approved · prescription only
- Australia
- Not on the ARTG
- Dose
- Set by the FDA label Dosing page
Dosing: the FDA label schedule.
What is abaloparatide?
Abaloparatide is a synthetic 34-amino-acid version (analogue) of human parathyroid hormone-related protein (PTHrP). It is designed to favour the shape of the PTH1 receptor linked to bone formation. It is injected once a day and approved under the brand Tymlos.
It works on the same general logic as teriparatide, a related PTH-pathway peptide. The two are different molecules, approved from separate trials.
US legal status - FDA-approved · prescription only
FDA-approved as Tymlos since 2017 for postmenopausal women, later expanded to men. Requires a prescription.
AU legal status - Not on the ARTG
I could not verify a Therapeutic Goods Administration approval or ARTG listing for abaloparatide.
Regulators reach their own conclusions on their own timelines. Where these two disagree, the difference is the point - not an error.
Abaloparatide structure
- Molecular formula
- C174H300N56O49
- Molecular weight
- 3961 g/mol
- Length
- 34 amino acids
- Sequence
- AVSEHQLLHDKGKSIQDLRRRELLEKLLXKLHTA
- Modifications
- X at position 29 = Aib (2-aminoisobutyric acid); C-terminal amide.
- PubChem CID
- 76943386
Tymlos contains abaloparatide itself; the diagram is the peptide.
Identity checked against KEGG DRUG.
Abaloparatide benefits: what the research shows
Consistent findings across large trials or meta-analyses. FDA approval rests on the ACTIVE trial, a randomised study in postmenopausal women with osteoporosis, controlled against both placebo and an active comparator. It found fewer new spine (vertebral) fractures and higher bone mineral density.
The pivotal ACTIVE trial Miller 2016 - Miller PD, Hattersley G, Riis BJ et al. Effect of Abaloparatide vs Placebo on New Vertebral Fractures in Postmenopausal Women With Osteoporosis: A Randomized Clinical Trial. JAMA. 2016;316(7):722-33., in the references below was randomised and controlled against both placebo and an active comparator, in postmenopausal women with osteoporosis. Abaloparatide reduced new spine fractures and increased bone mineral density compared with placebo. That trial is the human evidence behind FDA approval.
It is approved for:
- postmenopausal women with osteoporosis at high fracture risk
- men with primary or hypogonadal osteoporosis at high fracture risk, to increase bone density
Abaloparatide dosage
The approved dose is 80 mcg once a day, injected under the skin from a prefilled pen. Full schedule and duration guidance: abaloparatide dosage.
Abaloparatide side effects
Common side effects on the label:
- high urine calcium (hypercalciuria)
- dizziness
- nausea
- headache
- palpitations
It can also cause brief high blood calcium (hypercalcaemia) or a drop in blood pressure on standing (orthostatic hypotension) shortly after a dose. Full detail: abaloparatide side effects.
Is abaloparatide legal?
US legal status - FDA-approved · prescription only
An FDA-approved prescription medicine. It has been through clinical trials for its approved use, and legally requires a prescription from a licensed clinician.
AU legal status - Not on the ARTG
Not on the Australian Register of Therapeutic Goods, so the TGA has not assessed it for safety, quality or effectiveness. Goods that are not on the ARTG cannot lawfully be supplied or advertised in Australia except through a specific pathway - the Special Access Scheme, an Authorised Prescriber, a clinical trial, or personal importation.
Regulators reach their own conclusions on their own timelines. Where these two disagree, the difference is the point - not an error.
In the US it is FDA-approved and needs a prescription. I could not verify approval in Australia. It isn’t sold over the counter anywhere, and it is not the same product as an unlabelled “research” vial sold outside the approved supply chain.
Related reading
- Abaloparatide dosage: the FDA label schedule
- Teriparatide (Forteo): the related PTH-pathway peptide
- US peptide regulation tracker
How Abaloparatide compares
Bone health. Doses for unapproved compounds are common practice, not trial-established. All bone health peptides →
| Compound | Main use | Evidence | Usual dose | US status |
|---|---|---|---|---|
| Teriparatide | FDA-approved to treat osteoporosis in postmenopausal women and men at high fracture risk, and glucocorticoid-induced osteoporosis in men and women at high fracture risk, by stimulating new bone formation. | Strong human evidence | FDA label | FDA-approved · prescription only |
| Abaloparatide | FDA-approved to treat osteoporosis in postmenopausal women at high fracture risk, and to increase bone density in men with osteoporosis at high fracture risk, by stimulating new bone formation. | Strong human evidence | FDA label | FDA-approved · prescription only |
Where to get Abaloparatide legally
Abaloparatide is an FDA-approved prescription medicine, so the legal route is a licensed prescriber, in person or by telehealth, and a licensed pharmacy.
How telehealth prescribing works, what it costs and what to check: telehealth peptide prescribing.
Common questions
What is the usual abaloparatide dose?
The FDA-approved dose is 80 mcg injected under the skin once a day from a prefilled pen. See the dosing page for the full schedule.
What are the side effects of abaloparatide?
The label lists high urine calcium (hypercalciuria), dizziness, nausea, headache and palpitations as common. It also carries osteosarcoma warning language, and warns of brief high blood calcium or a drop in blood pressure on standing shortly after a dose. Full detail is on the dosing page.
How is abaloparatide different from teriparatide?
Both are FDA-approved, once-daily injected peptides that build bone through the PTH1 receptor. They are different molecules (abaloparatide mimics PTHrP; teriparatide is a fragment of PTH), approved from separate trials. FDA removed teriparatide's 2-year lifetime-use limit in 2020 after real-world safety data, while abaloparatide's label still advises against use beyond 2 years.
What are the negative side effects of Tymlos?
In the women's trial, the most common were high urine calcium, dizziness, nausea, headache, palpitations, fatigue, upper abdominal pain and vertigo. 10% stopped because of side effects, against 6% on placebo. The label also warns of a drop in blood pressure on standing, usually within 4 hours of a dose, brief high blood calcium, and osteosarcoma seen in rats. See the side effects section above.
What type of drug is abaloparatide?
A bone-building (anabolic) osteoporosis medicine. It is a synthetic version of parathyroid hormone-related protein (PTHrP) that activates the PTH1 receptor to stimulate bone-forming cells. It is a prescription peptide injected once a day and works on the same pathway as teriparatide.
Is abaloparatide safe?
It is FDA-approved for people with osteoporosis at high fracture risk, based on placebo-controlled trials including ACTIVE, but it isn't risk-free. The label carries osteosarcoma warning language from rat studies, warns of dizziness and a drop in blood pressure on standing after a dose, and advises against more than 2 years of use in a lifetime. A prescriber weighs those risks against fracture risk.
Who cannot take Tymlos?
The label's only contraindication is a history of severe allergic reaction to abaloparatide or its inactive ingredients. It also says to avoid it in people at higher baseline risk of osteosarcoma: open epiphyses (still-growing bones), bone diseases other than osteoporosis such as Paget's disease, bone metastases or skeletal cancers, past radiation therapy involving the skeleton, or inherited conditions that predispose to osteosarcoma. It is not recommended with existing high blood calcium, primary hyperparathyroidism, or beyond 2 years of lifetime treatment.
What is the brand name of abaloparatide?
Abaloparatide is sold under the brand name Tymlos, made by Radius Health. Tymlos is approved for osteoporosis in postmenopausal women at high risk of fracture, and increasing bone density in men with osteoporosis at high risk of fracture.
What is the generic name for Tymlos?
The generic name for Tymlos is abaloparatide. Tymlos is Radius Health's brand, approved for osteoporosis in postmenopausal women at high risk of fracture, and increasing bone density in men with osteoporosis at high risk of fracture.
Is Tymlos the same as abaloparatide?
Yes. Tymlos is a brand of abaloparatide, made by Radius Health: the active ingredient is abaloparatide. It comes as a once-daily subcutaneous injection (prefilled pen, 30 daily doses), dosed at 80 mcg once daily. Compounded or research-vial abaloparatide is not Tymlos and has not been through its FDA review.
References (2 sources)
Bibliographic detail is fetched from PubMed, not written by me - so a citation here cannot drift from the paper it names. Study design comes from PubMed's own tags rather than my judgement.
- 1.Miller PD, Hattersley G, Riis BJ et al. Effect of Abaloparatide vs Placebo on New Vertebral Fractures in Postmenopausal Women With Osteoporosis: A Randomized Clinical Trial. JAMA. 2016;316(7):722-33.Randomised trialPMID 27533157
- 2.TYMLOS (abaloparatide) injection - full prescribing information, including dosing, both approved populations and osteosarcoma warning language.- DailyMed, US National Library of Medicinelabel