Abaloparatide: evidence, FDA status and research

A daily injection that helps thinning bones. It has been tested well: in 2,463 women, far fewer new spine breaks happened than on a dummy shot.

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Abaloparatide is a prescription bone-building drug, and online discussion of it centres on whether it builds bone faster than teriparatide with less hypercalcemia.

Studies say

A large randomized trial showed fewer new spine and non-spine fractures over 18 months compared with placebo, which meets the bar for grade A for postmenopausal osteoporosis.

Why grade A. Approval for osteoporosis rests on ACTIVE, a randomized, double-blind, placebo- and active-controlled phase 3 trial in 2,463 postmenopausal women with fracture endpoints, plus the ATOM trial in 228 men with a bone-density endpoint. Fracture reduction in women was shown directly; the men's approval relies on bone density as a surrogate. ⁵⁶

FDA. Abaloparatide is FDA-approved and sold as Tymlos, a once-daily subcutaneous injection. It was approved in April 2017 for postmenopausal women with osteoporosis at high risk of fracture and in December 2022 to increase bone density in men with osteoporosis at high risk of fracture. ⁶⁷

Written from 8 cited sources. Fact-checked 2026-10-27: 14 claims checked, 0 corrected. Last refreshed 2026-10-27. Not physician reviewed.

What this means for you

What people take it for: Building stronger bones when they are thin and break easily.
Can a US doctor prescribe it?: Yes, FDA approved for thin bones (osteoporosis) in women after menopause and in men.
Properly tested in people?: Yes, in large controlled trials: 2,463 women were followed for 18 months.

Evidence checklist

Randomised controlled trial ACTIVE, placebo and teriparatide controlledyes
Human study over 100 people ACTIVE 2,463 women; ATOM 228 menyes
More than one research group Sponsor-run trials; no independent replication citedno information
Clinical outcomes, not surrogate markers Fracture reduction in womenyes
Human safety data beyond case reports Phase 3 safety plus label warningsyes

Drawn from the cited studies below. A dash means the sources give no information.

What it is

Abaloparatide is a lab-made peptide with 34 amino acids. It is modelled on parathyroid hormone-related protein (PTHrP), a natural hormone that helps control bone and calcium. Its first part matches PTHrP. It was built to switch on the same receptor as parathyroid hormone, but to favour bone growth over bone loss. ¹²

It is in the bone-building class of osteoporosis drugs. These drugs make new bone. Bisphosphonates only slow bone loss. The other peptide in this class is teriparatide, a piece of parathyroid hormone itself. Radius Health sells Tymlos as a prefilled pen. ⁶⁷⁸

How it works

Bone is always being rebuilt. Cells called osteoclasts break down old bone (resorption). Osteoblasts lay down new bone (formation). Abaloparatide binds the PTH1 receptor, a G-protein-coupled receptor on osteoblasts. A short daily switch-on of this receptor tips the balance toward growth. ²³

The drug binds best to a short-lived form of the PTH1 receptor. This gives a briefer signal than teriparatide does. That is the proposed reason it raises bone formation markers. It also causes less of the lasting calcium release seen with teriparatide. ²⁸

What human research shows

The ACTIVE trial randomized 2,463 postmenopausal women with osteoporosis. They got abaloparatide, placebo or open-label teriparatide for 18 months. New spine fractures hit 0.58% of women on abaloparatide and 4.22% on placebo. Non-spine fractures hit 2.7% versus 4.7%. Bone mineral density rose at the spine, hip and femoral neck, compared with placebo. ⁵

Next to teriparatide, abaloparatide gave bigger gains in total hip and femoral neck density at 18 months. It also caused less hypercalcemia (3.4% versus 6.4%). Fracture rates did not differ significantly between the two drugs. ⁵

The approval for men came from ATOM. This was a 12-month randomized placebo-controlled trial in 228 men with osteoporosis. Lumbar spine density rose 8.5% with abaloparatide versus 1.2% with placebo. The trial measured bone density, not fractures. ⁶

Study	Model	Finding
ACTIVE trial, JAMA 2016	Humans, n=2,463 postmenopausal women, randomized double-blind placebo- and teriparatide-controlled, 18 months	New vertebral fractures fell from 4.22% with placebo to 0.58% with abaloparatide, with fewer non-vertebral fractures and less hypercalcemia than teriparatide. ⁵
ATOM trial (men), FDA label 2022	Humans, n=228 men with osteoporosis, randomized placebo-controlled, 12 months	Lumbar spine bone density rose 8.5% versus 1.2% with placebo, supporting the men's indication on a surrogate endpoint. ⁶
Receptor pharmacology review	Receptor binding and signalling studies	Abaloparatide favours a transient PTH1 receptor conformation, consistent with a shorter calcium-mobilising signal than teriparatide. ²

Safety

The most common side effects in trials were hypercalciuria (extra calcium in urine), dizziness, nausea, headache, palpitations, fatigue, upper belly pain and vertigo. Orthostatic hypotension is a drop in blood pressure on standing. It can happen within hours of a dose. So the label says to give the first shots where the patient can sit or lie down. ⁶

Rats on abaloparatide got osteosarcoma, a bone cancer, and the risk rose with the dose. The label first had a boxed warning about this. The FDA removed it in late 2021 after reviewing post-marketing data from this drug and the related parathyroid hormone class. The risk now sits in the warnings section. The label still advises against the drug for people at higher baseline risk of osteosarcoma. These include people with Paget's disease of bone or past skeletal radiation. ⁶

Questions for your clinician

How does abaloparatide compare with other osteoporosis drugs for my fracture risk?
What did the rat osteosarcoma finding mean for people, and how long is treatment limited?
Should I take the first doses sitting or lying down because of dizziness?

Questions people ask

Is abaloparatide FDA-approved?

Yes. Tymlos was approved in 2017 for postmenopausal women with osteoporosis at high risk of fracture. In December 2022 it was approved for men with osteoporosis at high risk of fracture. ⁶⁷

How does abaloparatide differ from teriparatide?

Both switch on the PTH1 receptor and build bone. Abaloparatide is based on PTHrP, not on parathyroid hormone itself. It binds the receptor in a way that gives a shorter signal. In the ACTIVE trial it gave bigger hip density gains and about half the rate of hypercalcemia. Fracture rates were similar. ²⁵

Did the osteosarcoma warning go away?

The boxed warning was removed in late 2021. The label still lists the risk in its warnings section, based on rat studies. It advises against use in people with conditions that already raise osteosarcoma risk. ⁶

Does it reduce fractures or just improve bone density scans?

In postmenopausal women it cut real fractures in an 18-month randomized trial. In men the approval rested on bone density. That predicts fracture risk, but it is not a fracture count. ⁴⁵⁶

Citations

StatPearls: Abaloparatide ncbi.nlm.nih.gov
PMC review: PTH1 receptor pharmacology of abaloparatide pmc.ncbi.nlm.nih.gov
StatPearls: Physiology, bone remodeling ncbi.nlm.nih.gov
NIAMS: Bone mineral density tests, what the numbers mean niams.nih.gov
Miller 2016, JAMA: ACTIVE trial of abaloparatide vs placebo in postmenopausal osteoporosis jamanetwork.com
FDA: Tymlos (abaloparatide) prescribing information, 2024 accessdata.fda.gov
Radius Health: Tymlos product site tymlos.com
Biochemical Pharmacology 2019: abaloparatide, a first-in-class PTHrP analog sciencedirect.com