When your bones are weakening and fractures become a real fear, not just a worry, you need more than a pill that slows bone loss. You need something that rebuilds. That’s where teriparatide and
How These Drugs Actually Work
Both teriparatide and abaloparatide mimic natural signals in your body that tell bone cells to grow. Teriparatide is a piece of the parathyroid hormone (PTH), specifically the first 34 amino acids. Abaloparatide is a synthetic version of a similar hormone called PTHrP. Sounds technical? Here’s the simple version: your bones are alive. They’re constantly being broken down and rebuilt. Most osteoporosis drugs like bisphosphonates or denosumab just slow down the breakdown. These two drugs flip the script-they crank up the rebuilding.
The key difference? Abaloparatide is pickier. It binds more selectively to one version of the PTH receptor on bone cells. This means it pushes bone formation harder while stirring up less bone breakdown. Think of it like a precision tool versus a sledgehammer. That’s why, in clinical trials, abaloparatide showed less hypercalcemia (high calcium in the blood)-a common side effect with teriparatide. In the ACTIVE trial, 6.4% of people on teriparatide had high calcium levels. Only 3.4% on abaloparatide did. That’s a big deal when you’re already worried about kidney stones or heart rhythm issues.
Which One Builds Bone Better?
Let’s talk numbers. In the same 18-month ACTIVE trial, both drugs raised bone density, but abaloparatide pulled ahead in key spots. At the hip-where fractures are most dangerous-abaloparatide increased bone mineral density by 3.41%. Teriparatide? Just 2.04%. That’s a 1.37% difference. Sounds small? It’s not. That’s the difference between staying independent and needing a walker. For the femoral neck, the gap was 1.44%. That’s where hip fractures start. That’s where you don’t want to be weak.
At the spine, both worked well. Abaloparatide led early on, but by 18 months, the difference faded. That’s because spine bone turns over fast. The real win for abaloparatide? Fewer nonvertebral fractures. In the same trial, 1.9% of people on abaloparatide had a fracture outside the spine. On teriparatide? 3.86%. That’s nearly half the rate. And in a 2024 real-world study of over 43,000 women, abaloparatide users had 17% fewer hip fractures than those on teriparatide. That’s not a fluke. That’s a pattern.
Fracture Risk: The Real Bottom Line
It’s not about how much your bone density number goes up. It’s about whether you break a bone. That’s what matters when you’re 70 and you slip on ice. In the ACTIVE trial, abaloparatide cut new vertebral fractures by 86% compared to placebo. Teriparatide? 69%. That’s huge. But here’s the kicker: when researchers looked at hip fractures specifically, abaloparatide had a clear edge. The 2024 claims study showed 1.1% of abaloparatide users had a hip fracture over 18 months. For teriparatide users? 1.4%. That’s a 17% lower risk. In a population where even a 1% difference can mean the difference between living at home and moving to a nursing facility, that’s meaningful.
And the results stick. The ACTIVE-EXTEND trial followed patients for over 3 years. After 18 months on abaloparatide, they switched to alendronate (a common antiresorptive). The fracture protection didn’t vanish. It held. Only 2.1% of those patients had a new vertebral fracture over 5 years. Compare that to 5.8% in the group that started on alendronate right away. That’s why experts now say: start with an anabolic, then switch. Don’t just stay on one.
Safety: More Than Just Calcium Levels
Both drugs are injected daily under the skin. Side effects? Dizziness, nausea, leg cramps. But here’s where abaloparatide shines: fewer serious side effects. Hypercalcemia is the biggest concern with teriparatide. It’s not dangerous for most, but it can make you feel awful-fatigued, thirsty, confused. For someone with kidney disease or a history of kidney stones, that’s a dealbreaker. Abaloparatide’s cleaner receptor binding means fewer of these spikes.
There’s also the issue of discontinuation. In a 2024 survey of over 1,200 patients, 32% stopped teriparatide within a year. For abaloparatide? Only 24%. Why? Side effects. One Reddit user wrote: “Switched from teriparatide to abaloparatide after persistent hypercalcemia; calcium levels normalized within 3 months while maintaining BMD gains.” That’s not an outlier. That’s a pattern.
Injection site reactions? Slightly lower with abaloparatide. Dizziness? 41% of teriparatide users reported it. Only 29% on abaloparatide. That’s not just comfort-it’s safety. Falling during a dizzy spell can cause the very fracture you’re trying to prevent.
Cost and Access: The Hidden Barrier
Let’s be real. These drugs are expensive. As of early 2024, abaloparatide cost about $5,750 a month. Teriparatide? $4,200. And that’s before insurance. But here’s the twist: in January 2024, generic teriparatide hit the market. Teva Pharmaceuticals started selling it. The price dropped nearly 40%. That’s a game-changer. Suddenly, teriparatide isn’t just cheaper-it’s affordable for many without insurance.
Insurance coverage? That’s where things get messy. A 2023 analysis found 44% of abaloparatide users struggled to get coverage. For teriparatide? Only 28%. That’s not because it’s less effective. It’s because insurers see generic teriparatide as “good enough.” And for many patients, it is.
But cost isn’t just about the monthly price. It’s about what happens if you stop. If you can’t afford abaloparatide and switch to a cheaper drug too early, you lose bone gains. The data shows: staying on an anabolic for the full 18 months, then switching to an antiresorptive, gives the best long-term results. So if you can’t afford the full course? That’s a risk.
Who Gets Which Drug?
There’s no one-size-fits-all. But guidelines are starting to clarify. The American Association of Clinical Endocrinologists says: if you’re a woman with a hip T-score of -3.0 or lower, abaloparatide is the better first choice. Why? Because it builds hip bone better. If your spine is the weak spot and you’re cost-sensitive? Teriparatide still works great.
For men? The same data applies. Both drugs are approved for men with severe osteoporosis. But most studies focused on women. So doctors often use the same logic: if hip fracture risk is high, go with abaloparatide. If cost is tight and spine is the main concern, teriparatide is still a solid option.
And what about timing? You can only use either drug for 18 to 24 months total in your lifetime. After that, you switch to an antiresorptive-like alendronate, denosumab, or even a newer option. Why? Because long-term use hasn’t been proven safe. But here’s the good news: the bone you build during those 18 months can last. Studies show that patients who switch to alendronate after abaloparatide keep 80% of their bone gains five years later.
What’s Next?
The future is looking better. Radius Health is testing a weekly version of abaloparatide. If it works, adherence will jump. No more daily injections. No more forgetting. That’s huge. The FDA is also pushing for longer-term anabolic use. Right now, we’re limited to two years. But new data suggests we might be able to extend that safely.
And the market is shifting. Teriparatide still makes more money globally-but its dominance is slipping. Abaloparatide’s sales are climbing. And with more generics coming, the playing field is leveling. The real winner? Patients. We’re moving from “just slow the loss” to “actually rebuild.” That’s progress.
Practical Tips for Starting Treatment
- Store both drugs in the fridge. Keep them between 2°C and 8°C. Don’t freeze.
- Inject at the same time every day. Consistency matters. Morning is best to avoid nighttime dizziness.
- Use a logbook. Track your injections, side effects, and calcium levels. Bring it to every doctor visit.
- Get a DXA scan at 6 and 18 months. If your spine BMD didn’t rise at least 3% by 6 months, talk to your doctor. You might need a different plan.
- Plan your transition. Don’t stop cold. Talk to your doctor about what comes next-alendronate, denosumab, or another option.
These aren’t easy drugs to take. But for someone with severe osteoporosis, they’re life-changing. You’re not just treating a number on a scan. You’re protecting your ability to walk, to travel, to live without fear.
Can I take teriparatide or abaloparatide if I’ve had radiation therapy?
No. Both drugs carry a black box warning against use in people with a history of radiation therapy to the skeleton, bone cancer, or Paget’s disease. The risk of bone cancer (osteosarcoma) in animals was seen in long-term studies, and while human risk is low, it’s not zero. If you’ve had pelvic or spine radiation, your doctor will likely avoid these drugs and choose a different treatment path.
Do I need to take calcium and vitamin D with these drugs?
Yes. Absolutely. These drugs stimulate bone growth, but bone needs building materials. If your calcium or vitamin D levels are low, the drugs won’t work as well-and you’re more likely to get high calcium levels in your blood. Most doctors recommend at least 1,200 mg of calcium and 800-1,000 IU of vitamin D daily. Get your levels checked before you start.
How long does it take to feel the effects?
You won’t feel stronger right away. Bone rebuilding takes months. Most people don’t notice a difference in pain or mobility until after 6-9 months. But your bone density will start rising in 3-6 months. That’s why doctors use DXA scans-not how you feel-to judge if the drug is working.
Can I switch from teriparatide to abaloparatide?
Yes, but only if you haven’t used teriparatide for more than 18 months total. The lifetime limit for any anabolic agent is 24 months. If you’ve been on teriparatide for 12 months and your doctor thinks abaloparatide would be better, you can switch and use abaloparatide for the remaining 6-12 months. But you can’t do a full 18 months of each. The clock is on the total anabolic time, not per drug.
Are there any foods or supplements I should avoid?
Avoid excessive calcium supplements right before or after your injection. Too much calcium at once can trigger hypercalcemia. Stick to your daily dose spread across meals. Also, avoid high-dose vitamin D supplements unless your doctor orders them. Too much can raise calcium levels. Green leafy vegetables and dairy are fine-they provide calcium naturally and slowly.
If you’re considering one of these drugs, talk to your doctor about your fracture history, your hip and spine T-scores, your insurance, and your ability to stick with daily injections. There’s no perfect drug-just the right one for your body, your life, and your future.