Teriparatide vs Abaloparatide for Osteoporosis: What Works Better and Why

When your bones are breaking easily-maybe from a simple fall or even just standing up too fast-you need more than just a calcium pill. Osteoporosis isn’t just about getting older. It’s about losing bone strength so fast that everyday life becomes risky. For people with severe osteoporosis, especially those who’ve already had a fracture, standard drugs like bisphosphonates or denosumab often aren’t enough. That’s where anabolic agents come in. Unlike older drugs that slow bone loss, these medications actually build new bone. Two names stand out: teriparatide and abaloparatide.

What Makes These Drugs Different?

Teriparatide and abaloparatide both come as daily injections under the skin. They’re not pills. They’re not infusions. You have to stick yourself every day for up to 18 months. But that’s where the similarity ends.

Teriparatide, sold as Forteo, is a piece of your body’s own parathyroid hormone-specifically, the first 34 amino acids. It’s been around since 2002. Abaloparatide, sold as Tymlos, is a lab-made copy of a different hormone your body makes called PTHrP. It came out in 2017. On paper, they sound similar. But in practice, they work differently.

Here’s the key: teriparatide activates both sides of the bone-building process. It tells your body to make new bone, but it also briefly wakes up cells that break bone down. Abaloparatide is more selective. It leans heavily on the bone-building side and barely touches the bone-breaking side. That’s why, in studies, people on abaloparatide had fewer cases of high calcium in their blood-a common side effect of teriparatide.

Which One Builds Bone Better?

Let’s look at the numbers. In the ACTIVE trial, which tracked over 2,400 postmenopausal women with osteoporosis, abaloparatide showed stronger gains in bone density at the hip-where fractures are most dangerous. After 18 months, hip bone density increased by 3.41% with abaloparatide versus 2.04% with teriparatide. That’s a big difference when you’re trying to prevent a hip fracture.

At the spine, both drugs did well. Abaloparatide had a faster jump early on-6.58% at six months versus 5.25%-but by 18 months, the gap closed. That means if your main concern is spine fractures, either drug will help. But if you’ve had a fall before, or your hip T-score is below -3.0, abaloparatide gives you a clearer edge.

Real-world data backs this up. A 2024 study of over 43,000 women found that those on abaloparatide had 17% fewer hip fractures than those on teriparatide. That might sound small-0.3% difference-but for someone at high risk, that’s the difference between staying on your feet and needing surgery.

Side Effects: More Than Just a Shot

Both drugs can cause dizziness, nausea, or leg cramps. But the big difference is in how often they raise your blood calcium.

Teriparatide leads to high calcium in about 6.4% of users. Abaloparatide? Just 3.4%. That’s nearly half the rate. Why does it matter? High calcium can make you feel tired, throw off your heart rhythm, or even cause kidney stones. One Reddit user switched from teriparatide to abaloparatide after months of persistent high calcium levels. Within three months, his levels normalized-and his bone density stayed strong.

Injection site reactions are common with both, but slightly less so with abaloparatide. About 52% of abaloparatide users reported redness or itching at the injection site, compared to 68% on teriparatide. Dizziness was also less frequent: 29% vs 41%.

And here’s something most doctors don’t talk about enough: discontinuation rates. In a 2024 survey of over 1,200 patients, 32% stopped teriparatide within a year. Only 24% stopped abaloparatide. The main reason? Side effects-especially high calcium.

Cost and Access: The Hidden Barrier

Abaloparatide costs about $5,750 a month. Teriparatide? Around $4,200. That’s not just a few bucks. That’s thousands. And it’s not just the price tag-it’s insurance.

A 2023 analysis showed 44% of abaloparatide users struggled to get coverage. For teriparatide, it was 28%. Why? Because teriparatide went generic in January 2024. Teva Pharmaceuticals started selling it for a fraction of the cost. Suddenly, the price gap widened. Many insurers now require patients to try the generic version first.

That’s a problem. Because if you’re at high risk for hip fracture, you might need the better-performing drug right away. But insurers don’t always see it that way. Some patients end up on teriparatide first, only to switch later when side effects hit-and by then, they’ve lost valuable time.

Who Gets Which Drug?

Guidelines from the American Association of Clinical Endocrinologists (AACE) in 2023 are clear: if you have severe osteoporosis with a hip T-score of -3.0 or lower, abaloparatide is the preferred choice. For everyone else? Teriparatide is still the first-line option-mostly because it’s cheaper and has 20 years of real-world data behind it.

Dr. Benjamin Leder, who led the main trial on abaloparatide, says its selective action on bone-forming cells makes it ideal for patients who need fast, strong results. Dr. Ethel Siris, on the other hand, argues that the small fracture reduction advantage doesn’t justify the cost for most people. That’s the debate in a nutshell.

But here’s what matters most: if you’ve broken a bone already, or your doctor says you’re at high risk, you need an anabolic agent. Neither drug works if you’re only taking it for six months. You need the full 18-24 months. And you need to follow it up with a drug like alendronate or denosumab to keep the new bone from melting away.

What Happens After the Injections?

These drugs aren’t meant to be lifelong. After 18 months, your body gets used to them. That’s why doctors always pair them with an antiresorptive drug afterward.

The ACTIVE-EXTEND trial showed that if you switch from abaloparatide to alendronate, you keep 68% of your hip bone density gains after 3.5 years. Without that follow-up, you lose most of the progress. That’s why timing matters. Don’t stop the injection and do nothing. Talk to your doctor about what comes next.

What’s Coming Next?

Both drugs are being improved. Radius Health is testing a weekly version of abaloparatide. If it works, it could solve the biggest problem: sticking to daily shots. Right now, only about 60% of patients complete the full 18-month course. A weekly shot could change that.

The FDA is also encouraging research into longer-term use. Right now, the limit is 24 months. But new data suggests some patients might benefit from longer courses-especially if they’re on a protective drug after.

The market is shifting too. Teriparatide’s sales dropped after generics arrived, but abaloparatide’s growth is slowing because of cost. Still, the global osteoporosis market is expected to hit $14.7 billion by 2028. Aging populations mean more people will need these drugs. The question isn’t whether we need them-it’s who gets access to the best one.

Practical Tips for Patients

• Store both drugs in the fridge. They’re sensitive to heat. Don’t leave them on the counter.
• Inject at the same time every day. Consistency helps your body respond better.
• Track your calcium levels. Get a blood test at 4 and 8 weeks after starting. If your calcium is high, talk to your doctor.
• Don’t skip doses. Even one missed day can reduce effectiveness. Use phone alarms.
• Plan for the next step. Ask your doctor about what drug you’ll take after 18 months. Don’t wait until the injection runs out.

Final Thoughts

There’s no single ‘best’ drug for everyone. If cost is tight and your fracture risk is moderate, teriparatide still delivers strong results. But if your hip is weak, you’ve had a fall, or you can’t tolerate high calcium, abaloparatide is the smarter choice. It’s not just about numbers on a scan-it’s about staying independent, avoiding surgery, and living without fear.

The science is clear: these drugs rebuild bone. The real challenge is making sure the right person gets the right drug at the right time-and that insurance doesn’t get in the way.