When your bones are weakening and fractures become a real fear, treatment isn’t just about slowing down damage-it’s about rebuilding. For people with severe osteoporosis, especially those who’ve already broken a bone or have T-scores below -3.0, two drugs stand out: teriparatide and abaloparatide. These aren’t your typical osteoporosis pills. They’re anabolic agents, meaning they actually stimulate your body to grow new bone, not just stop it from breaking down. If you’re considering these treatments, you need to know how they differ, what the data says, and which one might actually work better for you.
How These Drugs Actually Work
Both teriparatide and abaloparatide mimic natural signals in your body that tell bone cells to build more bone. Teriparatide is a piece of human parathyroid hormone-specifically, the first 34 amino acids. It’s been around since 2002 and was the first drug of its kind approved by the FDA. Abaloparatide, approved in 2017, is a synthetic version of a different hormone called PTHrP. It’s designed to bind more selectively to the receptor on bone cells.
This small difference in molecular shape matters. Abaloparatide favors a specific receptor shape (the RG conformation) that triggers bone formation more strongly while causing less bone breakdown. Teriparatide activates both bone-building and bone-resorbing pathways more equally. That’s why abaloparatide often leads to bigger gains in hip bone density-where fractures are most dangerous-and why it causes fewer cases of high calcium levels in the blood.
Fracture Reduction: The Real Goal
Everyone wants to avoid another fracture. The ACTIVE trial, which followed over 2,400 postmenopausal women for 18 months, showed abaloparatide cut new vertebral fractures to just 0.58% compared to 4.22% in the placebo group. Teriparatide also reduced fractures, but direct comparisons show abaloparatide had a slight edge in nonvertebral fractures, especially hip fractures.
A 2024 study of over 43,000 women found that those on abaloparatide had a 17% lower risk of hip fracture than those on teriparatide. That might sound small, but for someone with a T-score of -3.2 or worse, it’s meaningful. Hip fractures in older adults often lead to long-term disability or even death. Reducing that risk-even by a few percentage points-is a big win.
Both drugs reduce spine fractures by over 80% compared to no treatment. But if your biggest concern is falling and breaking your hip, abaloparatide’s data is stronger.
Bone Density Gains: Numbers That Matter
DXA scans measure bone mineral density (BMD), and these drugs make it go up-fast. After 18 months:
- Abaloparatide increases lumbar spine BMD by about 9.5%
- Teriparatide increases lumbar spine BMD by about 8.7%
- Abaloparatide boosts total hip BMD by 3.4%
- Teriparatide boosts total hip BMD by just 2.0%
The hip numbers are especially important. Most osteoporosis drugs don’t help the hip much. But abaloparatide does. In fact, over half of women starting with a total hip T-score as low as -2.7 reached a safer level above -2.5 after 18 months on abaloparatide. Teriparatide got most people there too-but slightly fewer.
At six months, abaloparatide already showed significantly greater gains in the hip. That’s useful if you need quick results before switching to a maintenance drug.
Safety: Hypercalcemia and Side Effects
One of the biggest differences between the two is side effects. Teriparatide causes high calcium levels in the blood (hypercalcemia) in about 6.4% of users. Abaloparatide? Only 3.4%. That’s nearly half the rate.
Why? Because abaloparatide doesn’t overstimulate the receptor pathways that cause calcium to leak out of bone into the bloodstream. That’s why patients switching from teriparatide to abaloparatide often report their calcium levels normalize within months.
Other common side effects include dizziness, nausea, and leg cramps. Patient surveys show 41% of teriparatide users report dizziness, compared to 29% on abaloparatide. Injection site reactions are also slightly more common with teriparatide-68% vs. 52%.
Neither drug is linked to jaw bone problems or atypical femur fractures like some other osteoporosis treatments. Both are safe for up to 24 months of use. After that, you switch to an antiresorptive like alendronate or denosumab to lock in the gains.
Cost and Access: The Practical Reality
Cost is where things get messy. In 2024, abaloparatide cost about $5,750 per month. Teriparatide, now available as a generic since January 2024, costs around $4,200. That’s a 30% difference. And it’s not just the sticker price-insurance approval is harder for abaloparatide. A 2023 analysis found 44% of abaloparatide users had coverage issues, compared to 28% for teriparatide.
Some patients pay out of pocket for abaloparatide because their doctor says it’s the better choice. Others stick with teriparatide because their insurance won’t cover the other. The American Association of Clinical Endocrinologists still recommends teriparatide as first-line because of its long track record and lower cost. But they specifically recommend abaloparatide for patients with severe hip osteoporosis (T-score ≤-3.0).
There’s also a practical side: you have to inject yourself every single day. Miss a day, and you lose the benefit. Some people struggle with the routine. A 2024 survey found 32% of teriparatide users stopped treatment within a year, compared to 24% on abaloparatide. The lower side effects of abaloparatide might help with adherence.
What Happens After 18 Months?
Neither drug is meant to be taken forever. The FDA limits both to 24 months total in a lifetime because of a small risk of bone cancer in rats (never seen in humans). After 18 months, you switch to a bone-preserving drug like alendronate, risedronate, or denosumab.
The ACTIVE-EXTEND trial showed that if you take abaloparatide for 18 months and then switch to alendronate, you keep most of your bone gains. At 3.5 years, 68% of patients still had a total hip T-score above -2.5. That’s a big deal. If you don’t follow up with an antiresorptive, you’ll lose most of the gains within a year.
Doctors now recommend checking your BMD at 6 and 18 months. If your spine BMD hasn’t increased by at least 3% by six months, you might not be responding well-and you should talk to your doctor about alternatives.
What’s Coming Next?
Researchers are already working on better versions. Radius Health is testing a weekly injection of abaloparatide. If it works, it could solve the biggest problem with both drugs: daily injections. A Phase 3 trial finished enrollment in December 2023, with results expected in late 2025.
The FDA is also encouraging drugmakers to study longer treatment durations. Right now, we’re stuck with 18-24 months. But what if you could take an anabolic agent for a year, then pause, then restart? That’s the next frontier.
Meanwhile, the market is shifting. Generic teriparatide is driving down prices. By 2025, its cost could drop another 40%. That could make it the default choice for many, even if abaloparatide is technically better.
So Which One Should You Choose?
There’s no one-size-fits-all answer. Here’s a simple guide:
- Choose abaloparatide if: You have a hip T-score of -3.0 or worse, you’ve had a nonvertebral fracture before, you’re prone to high calcium levels, or you can afford it and get insurance approval.
- Choose teriparatide if: Cost or insurance is a barrier, your main concern is spine fractures, you’ve used it before and tolerated it well, or you’re looking for the most proven option with the longest real-world data.
Both drugs are better than nothing. If you’re at high risk for fracture, not treating osteoporosis is the biggest danger. Talk to your doctor about your fracture history, your hip BMD, your budget, and your tolerance for side effects. The right choice isn’t just about science-it’s about what works for your life.
What Patients Are Saying
Real people have real experiences. On patient forums, some say:
"Switched from teriparatide to abaloparatide after persistent hypercalcemia; calcium levels normalized within 3 months while maintaining BMD gains." - Reddit user BoneWarrior42
"Teriparatide worked better for my lumbar spine density (12.3% increase vs 9.8% with abaloparatide), but I couldn’t tolerate the dizziness episodes." - Reddit user FractureFree88
These aren’t outliers. They’re reflections of the data: abaloparatide is gentler on the body, teriparatide might work better for the spine in some cases. But for most people with high hip fracture risk, abaloparatide offers a better balance of safety and effectiveness.
Can I take teriparatide and abaloparatide together?
No. Both drugs work the same way and are only approved for use one at a time. Taking them together offers no benefit and increases side effect risks. You must choose one, use it for up to 24 months, then switch to a different type of osteoporosis medication.
How long do I need to take these drugs before I see results?
Bone density changes are measurable by DXA scan after 6 months, but the biggest improvements happen between 12 and 18 months. Fracture risk reduction takes longer to prove-studies show clear benefits after 18 months of treatment. Don’t expect immediate results; this is a long-term rebuild.
Are there alternatives to injections?
Yes, but they’re not anabolic. Oral bisphosphonates like alendronate or injectables like denosumab stop bone loss but don’t build new bone. If your goal is to reverse severe osteoporosis, injections like teriparatide or abaloparatide are currently the only options that stimulate bone formation. A weekly abaloparatide injection is in development and may become available by 2026.
Can men use these drugs too?
Yes. Both teriparatide and abaloparatide are FDA-approved for men with severe osteoporosis who are at high risk of fracture. The same dosing, safety profile, and treatment duration apply. Men with low testosterone or long-term steroid use often benefit the most.
What if I can’t afford either drug?
Talk to your doctor about patient assistance programs. Eli Lilly offers savings cards for teriparatide, and Radius Health has similar support for abaloparatide. Generic teriparatide is now available and costs significantly less. If cost is prohibitive, your doctor may recommend starting with an antiresorptive like denosumab or a bisphosphonate to reduce fracture risk while you explore options.
Do I need to take calcium and vitamin D with these drugs?
Absolutely. Both drugs require adequate calcium and vitamin D to work. If your levels are low, your bones won’t respond well. Most doctors recommend at least 1,200 mg of calcium and 800-1,000 IU of vitamin D daily. Blood tests before starting are standard to make sure you’re not deficient.
Can I exercise while on these drugs?
Yes-and you should. Weight-bearing exercise like walking, resistance training, and balance work helps the drugs work better. Bone responds to mechanical stress, so combining medication with physical activity gives you the best chance of rebuilding strength. Avoid high-impact activities if you’ve had fractures, but low-impact strength training is encouraged.
Final Thoughts
Teriparatide and abaloparatide aren’t just drugs-they’re tools for rebuilding. If you’ve been told your bones are dangerously weak, these are among the most powerful options available. Abaloparatide offers slightly better hip protection and fewer side effects. Teriparatide is the proven, more affordable choice. Neither is perfect. But both are far better than doing nothing.
The future of osteoporosis treatment is moving toward personalized, sequential therapy: an anabolic agent to rebuild, then a long-term maintenance drug to preserve. By 2028, this approach will be standard. Right now, the choice comes down to your fracture risk, your budget, and your tolerance for side effects. Talk to your doctor. Get your numbers. Make the decision that fits your life-not just the data.
