Abaloparatide rebuilds bone, fast.
If your doctor told you a fracture changed everything, you already know the fear of the next one. Maybe a wrist snapped on a curb. Maybe a vertebra cracked from leaning into a kitchen drawer. Abaloparatide is one of the few drugs that can actually grow new bone instead of just slowing the loss, and that distinction matters when you are standing in a pharmacy trying to decide what to inject for the next 18 months.
🔑 Key Takeaways
- Abaloparatide is a synthetic PTHrP analog that builds bone, not just preserves it.
- It is sold as Tymlos in the US and Eladynos in Europe.
- One 80 mcg subcutaneous injection daily, capped at 18 months lifetime.
- In the ACTIVE trial, the drug cut new vertebral fractures by 86% vs placebo.
- The old osteosarcoma boxed warning was removed by the FDA in 2022.
- Most common side effects: dizziness, nausea, headache, palpitations, injection-site redness.
What abaloparatide actually does
Most osteoporosis drugs slow bone breakdown. This one does the opposite. It tells the body to lay down new bone, which is why it is classed as an anabolic agent rather than an antiresorptive.
The molecule is a 34-amino-acid synthetic version of parathyroid hormone-related protein (PTHrP). It binds selectively to the PTH1 receptor on osteoblasts, the cells that build bone. That selective binding is the reason this drug drives a faster, larger jump in bone density at the hip than its older cousin teriparatide does in the same time window.
Who abaloparatide is approved for
The FDA approved Tymlos in April 2017 for postmenopausal women with osteoporosis at high risk of fracture. In December 2022, the label expanded to include men with osteoporosis at high risk of fracture. The European Union approved the drug as Eladynos in December 2022 for the same postmenopausal indication.
"High risk" usually means one of three things: a previous osteoporotic fracture, a very low T-score (typically below -2.5 with risk factors), or failure to respond to bisphosphonates like alendronate.
Dose, injection, and timing
| Detail | Specifics |
|---|---|
| Standard dose | 80 mcg subcutaneous, once daily |
| Injection sites | Periumbilical region of the abdomen (rotate sites) |
| Best time of day | Same time daily; many patients prefer evening to reduce orthostatic dizziness during the day |
| Maximum course | 18 months cumulative lifetime use |
| Pen storage | Refrigerate before first use; in-use pen good 30 days at room temp under 25 C |
| Missed dose | Take that day if remembered the same day; skip if next day arrived. Never double up. |
The pen comes pre-filled, delivers 30 doses, and clicks audibly when fired. Most users describe the injection as a brief sting, similar to insulin pens.
Abaloparatide vs teriparatide (Forteo)
This is the comparison that matters, because both drugs hit the same receptor and treat the same patients. Teriparatide came first in 2002. The newer option arrived in 2017 with a head-to-head trial built into its phase III program.
| Feature | Abaloparatide (Tymlos) | Teriparatide (Forteo) |
|---|---|---|
| Origin | PTHrP analog, 34 amino acids | PTH(1-34) fragment |
| Daily dose | 80 mcg SC | 20 mcg SC |
| Hip BMD gain at 18 months | ~3.4% | ~2.0% |
| Vertebral fracture risk reduction (vs placebo) | 86% | ~65% |
| Hypercalcemia rates | Lower (about 3.4%) | Higher (about 6.4%) |
| Brand cash price (US, monthly) | $1,800 to $2,400 | $3,500 to $4,200 |
| Refrigeration | Only before first use | Always refrigerated |
Tymlos builds hip bone faster, has fewer episodes of high blood calcium, and costs less per month. Teriparatide has the longer real-world track record. For most postmenopausal women with high fracture risk, the newer agent is now the first-choice anabolic.
Side effects worth knowing about
The side effects that show up most often in trial data and pharmacy reports:
- Dizziness and orthostatic hypotension. About 1 in 10 patients feel lightheaded after the first few doses. Inject sitting or lying down for the first week.
- Hypercalciuria. Calcium levels in the urine climb in roughly 1 in 5 users, which can occasionally trigger kidney stones.
- Nausea, headache, palpitations, fatigue. Usually peaks in the first month and fades.
- Injection-site reactions. Mild redness and itching at the abdominal site is common but rarely treatment-limiting.
- Joint and back pain. Reported by 5 to 10% of users.
About the old osteosarcoma warning
Until 2022, the drug carried a boxed warning about a rat-study cancer signal. The FDA removed that warning in 2022 after long-term human surveillance found no increased osteosarcoma risk in people. Tymlos is still avoided in patients with Paget's disease, prior radiation to bones, or unexplained elevated alkaline phosphatase, but the boxed warning is gone.
What happens after the 18 months are up
Anabolic gains fade if nothing follows. The standard sequence after stopping abaloparatide is an antiresorptive, usually alendronate or denosumab, to lock in the new bone. The ACTIVExtend study showed that two years of alendronate after the active phase preserved most of the bone density gain and kept fracture risk suppressed.
Skipping the follow-on therapy lets bone turnover rebound and erases part of what was built. Do not end an 18-month course without a clear next-drug plan in writing.
Cost and insurance reality
List price for a 30-day Tymlos pen runs about $2,200 in the US. Most commercial insurance covers it for patients with a documented fracture history or a failed bisphosphonate trial, with copays in the $30 to $150 range. Medicare Part D plans usually require step therapy.
The manufacturer copay card (for commercially insured US patients) can drop out-of-pocket cost to as low as $4 per month. Cash-pay patients should ask the pharmacist about manufacturer patient assistance programs before paying full price.
Where abaloparatide fits in the broader peptide picture
Tymlos is a prescription bone-building peptide and lives in a different category from the recovery and longevity peptides on PeptideDeck. If you are researching how peptide therapies work in general, the list of peptides and their uses covers the broader landscape, and the peptides for beginners guide explains how injection-based peptide therapy fits into a real routine. For bone and joint recovery questions specifically, our BPC-157 dosage guide and TB-500 dosage guide cover the most-asked dosing questions.
If you are using a pen-injectable like this one and also working with reconstituted vials for other peptides, the reconstitution calculator handles the dose math.
Medical disclaimer: This article is for general education only and is not medical advice. Abaloparatide is a prescription medication that must be initiated and supervised by a licensed clinician. Talk to your doctor about whether it is right for you, especially if you have a history of cancer, kidney stones, or elevated calcium.