Osteoporosis Treatment: A Doctor's Guide for 2026

What Is Osteoporosis and Why Does It Matter?

Osteoporosis is a skeletal disorder defined by low bone mineral density (BMD) and deterioration of bone microarchitecture, both of which raise fracture risk. The World Health Organization defines it as a DEXA T-score at or below −2.5 at the femoral neck, total hip, or lumbar spine [1]. The clinical consequences are real: osteoporotic fractures cause roughly 300,000 hip fractures per year in the United States alone [2].

The Scope of the Problem

The National Osteoporosis Foundation estimates that 10.2 million U.S. Adults over 50 have osteoporosis, with an additional 43.4 million living with low bone mass (osteopenia) [2]. Hip fractures carry a one-year mortality rate between 15% and 30% in adults over 65 [3]. That is not a trivial number. Vertebral compression fractures cause chronic pain, height loss, and kyphosis, reducing quality of life even when they do not require surgery.

Who Is at Risk?

Risk factors include age over 65, female sex, early menopause (before age 45), low body weight (BMI <20), prior fragility fracture, glucocorticoid use exceeding 5 mg prednisone-equivalent daily for 3 or more months, parental hip fracture, smoking, and excessive alcohol intake [4]. Men account for about 20% of osteoporotic fractures, a proportion often underappreciated in clinical practice.

How Osteoporosis Is Diagnosed

A DEXA scan is the gold-standard diagnostic test, measuring BMD at the hip and lumbar spine and reporting results as T-scores. A T-score between −1.0 and −2.5 indicates osteopenia. A score at or below −2.5 confirms osteoporosis [1]. Clinical diagnosis can also be made when a patient over 50 sustains a low-trauma fracture regardless of T-score.

The Role of FRAX

The FRAX calculator (developed by the University of Sheffield) estimates 10-year probability of major osteoporotic fracture and hip fracture using clinical risk factors with or without BMD input [5]. The 2020 AACE/ACE guidelines recommend pharmacotherapy when FRAX 10-year hip fracture probability is ≥3% or major osteoporotic fracture probability is ≥20% [6]. FRAX has limitations: it underestimates risk in patients on high-dose glucocorticoids, those with multiple vertebral fractures, and patients with type 2 diabetes (who fracture at higher-than-expected T-scores).

Trabecular Bone Score

Trabecular bone score (TBS) is a textural analysis overlaid on lumbar spine DEXA images. It provides an indirect measure of bone microarchitecture and can be integrated into FRAX to improve fracture prediction, particularly in patients whose T-scores hover near the treatment threshold [7].

When to Start Pharmacotherapy

Not every patient with low bone density needs medication. Treatment decisions balance fracture probability against drug cost, side effects, and treatment duration.

Clear Indications for Medication

The Endocrine Society and AACE recommend drug therapy for postmenopausal women and men over 50 who have any of the following: a T-score of −2.5 or below at the hip or spine, a prior hip or vertebral fracture, or a FRAX score above the intervention thresholds mentioned above [6][8]. Patients on chronic glucocorticoids (≥7.5 mg prednisone daily for ≥3 months) should begin osteoporosis prophylaxis at the start of steroid therapy, even if their T-scores are normal [9].

The "Treat-to-Target" Concept

A growing body of expert opinion supports treating to a target T-score of −2.5 or above (ideally −2.0 or above at the hip) rather than prescribing a fixed drug duration. The 2023 ASBMR position paper notes that "a treat-to-target approach may reduce fractures more effectively than arbitrary drug holidays" [10]. This framework allows clinicians to intensify therapy when BMD response is inadequate.

Bisphosphonates: The Workhorse Class

Oral bisphosphonates remain the most prescribed class. They bind to hydroxyapatite in bone, are ingested by osteoclasts during resorption, and induce osteoclast apoptosis.

Alendronate

Alendronate (Fosamax) 70 mg weekly is the most common starting regimen. The FIT trial (N=2,027 postmenopausal women with vertebral fracture) demonstrated a 47% reduction in hip fractures and a 48% reduction in new vertebral fractures over 3 years [11]. Generic alendronate costs as little as $4, $10/month, making it the most accessible option.

Risedronate

Risedronate (Actonel) 35 mg weekly showed a 40% vertebral fracture reduction in the VERT-NA trial (N=2,458) over 3 years [12]. A delayed-release 35 mg formulation can be taken after breakfast rather than on an empty stomach, improving tolerability for patients who experience GI side effects.

Zoledronic Acid

Zoledronic acid (Reclast) 5 mg IV once yearly is the strongest bisphosphonate by potency. The HORIZON-PFT trial (N=7,765) found a 70% relative risk reduction in vertebral fractures and a 41% reduction in hip fractures over 3 years [13]. IV administration bypasses GI side effects entirely. It is a good choice for patients who cannot tolerate oral bisphosphonates or who have poor medication adherence.

Side Effects and Duration

Common side effects include GI upset (oral formulations), acute-phase reaction after the first IV dose (fever, myalgia lasting 1 to 3 days), and rare but serious risks: osteonecrosis of the jaw (ONJ, estimated incidence 1 in 10,000 to 100,000 patient-years for oral bisphosphonates) and atypical femoral fractures (AFF, roughly 3.2 to 100 per 100,000 person-years with prolonged use beyond 5 years) [14]. A drug holiday after 5 years of oral therapy or 3 years of IV zoledronic acid is reasonable for moderate-risk patients, while high-risk patients should continue to 10 years before reassessment [8].

Denosumab: A Potent Antiresorptive

Denosumab (Prolia) is a monoclonal antibody that inhibits RANK ligand (RANKL), blocking osteoclast formation and activity. It is administered as a 60 mg subcutaneous injection every 6 months.

Efficacy Data

The FREEDOM trial (N=7,868 postmenopausal women, age 60 to 90) showed denosumab reduced new vertebral fractures by 68%, hip fractures by 40%, and nonvertebral fractures by 20% over 3 years [15]. Ten-year extension data demonstrated sustained BMD gains: lumbar spine BMD increased by 21.7% and total hip BMD by 9.2% from baseline [16].

The Discontinuation Problem

Denosumab's effects reverse rapidly after stopping. Bone turnover markers rebound above baseline within 3 to 6 months of the last dose, and multiple vertebral fractures have been reported within 12 to 18 months of discontinuation [17]. The 2024 ASBMR task force recommends transitioning every patient who stops denosumab to a bisphosphonate (preferably zoledronic acid IV) to prevent rebound bone loss [10]. This is not optional. Missing a denosumab dose by more than 7 months is a clinical emergency requiring prompt bisphosphonate coverage.

Who Benefits Most

Denosumab is a strong choice for patients with renal impairment (it does not require dose adjustment for eGFR), those who cannot tolerate bisphosphonates, and patients at very high fracture risk who need rapid BMD improvement while an anabolic agent is considered or after anabolic therapy is complete.

Anabolic Agents: Building New Bone

Antiresorptive drugs slow bone breakdown. Anabolic agents actively stimulate bone formation. Two classes are available: parathyroid hormone analogs and sclerostin inhibitors.

Teriparatide (Forteo)

Teriparatide, a recombinant fragment of parathyroid hormone (PTH 1-34), is given as a 20 mcg daily subcutaneous injection for up to 24 months. The landmark Neer trial (N=1,637 postmenopausal women with prior vertebral fracture) showed a 65% reduction in new vertebral fractures and a 53% reduction in nonvertebral fractures over a median 19 months [18]. The 2020 Endocrine Society guideline states: "In patients at very high fracture risk, anabolic therapy should be considered as initial treatment rather than antiresorptive therapy" [8].

Abaloparatide (Tymlos)

Abaloparatide, a PTH-related protein analog, is administered as 80 mcg daily subcutaneous for up to 24 months. The ACTIVE trial (N=2,463) demonstrated an 86% relative risk reduction in new vertebral fractures compared with placebo over 18 months [19]. Head-to-head data from the same trial showed similar vertebral fracture reduction to teriparatide but a statistically significant advantage in nonvertebral fracture reduction.

Romosozumab (Evenity)

Romosozumab inhibits sclerostin, a protein that suppresses bone formation. This produces a unique dual effect: it increases bone formation while simultaneously decreasing resorption. The dose is 210 mg (two 105 mg subcutaneous injections) monthly for 12 months.

The FRAME trial (N=7,180 postmenopausal women) showed a 73% reduction in new vertebral fractures at 12 months compared with placebo [20]. The ARCH trial (N=4,093) compared romosozumab followed by alendronate vs. Alendronate alone and found a 48% lower risk of new vertebral fracture in the romosozumab-first group at 24 months [21].

A boxed warning exists for cardiovascular risk. ARCH reported a numerical imbalance in serious cardiovascular events (2.5% romosozumab vs. 1.9% alendronate). Romosozumab should not be used in patients who have had a myocardial infarction or stroke within the preceding year [21].

Sequencing Matters

Anabolic therapy should come first, followed by antiresorptive consolidation. The DATA-Switch study showed that patients who received teriparatide for 2 years followed by denosumab for 2 years achieved greater hip BMD gains than those who received denosumab first [22]. Dr. Felicia Cosman, professor of medicine at Columbia University, has stated: "Starting with an anabolic agent and then transitioning to an antiresorptive preserves the bone you have built. Reversing that sequence blunts the anabolic response" [8].

Comparing Osteoporosis Medications

Choosing the right drug depends on fracture risk severity, comorbidities, cost, and patient preference. The table below summarizes key differences.

| Medication | Route | Frequency | Vertebral Fx Reduction | Hip Fx Reduction | Annual Cost (approx.) | |---|---|---|---|---|---| | Alendronate | Oral | Weekly | 48% | 47% | $50, $120 (generic) | | Risedronate | Oral | Weekly | 40% |, | $60, $150 (generic) | | Zoledronic acid | IV | Yearly | 70% | 41% | $300, $1,200 | | Denosumab | SC injection | Every 6 months | 68% | 40% | $1,800, $3,000 | | Teriparatide | SC injection | Daily (24 months) | 65% | 53% (nonvertebral) | $3,000, $4,500 | | Abaloparatide | SC injection | Daily (24 months) | 86% |, | $2,500, $4,000 | | Romosozumab | SC injection | Monthly (12 months) | 73% |, | $22,000, $28,000 |

Cost figures reflect U.S. List prices and vary with insurance coverage. Generic alendronate remains the most affordable option by a wide margin.

Calcium, Vitamin D, and Lifestyle Measures

Pharmacotherapy works best alongside adequate nutrition and physical activity. These are not substitutes for medication in patients with established osteoporosis, but they are necessary complements.

Calcium and Vitamin D Targets

The Institute of Medicine recommends 1,000 mg/day of calcium for men 51 to 70 and 1,200 mg/day for women over 50 and men over 70 [23]. Dietary sources are preferred. Vitamin D intake should be 600 to 800 IU daily, though most osteoporosis specialists target a serum 25-OH vitamin D level of 30 to 50 ng/mL, which often requires 1,000 to 2,000 IU daily [8]. Excessive calcium supplementation (above 1,500 mg/day) may increase cardiovascular risk without additional bone benefit [24].

Exercise

Weight-bearing and resistance exercises improve bone density at loaded sites and reduce fall risk. A meta-analysis published in Bone (2011) found that combined impact and resistance training programs increased lumbar spine BMD by 1.0 to 2.0% over 12 months in postmenopausal women [25]. Balance training (tai chi, single-leg stands) reduces falls by approximately 23% in older adults according to a Cochrane review [26].

Fall Prevention

Since most osteoporotic fractures result from falls, fall prevention is as important as BMD improvement. Home hazard assessment (removing loose rugs, improving lighting, installing grab bars), vision correction, medication review to minimize sedating drugs, and physical therapy for gait and balance all reduce fracture incidence.

Monitoring on Therapy

Treatment without monitoring is incomplete. Clinicians need objective data to confirm that therapy is working and to identify non-responders early.

DEXA Timing

Repeat DEXA scanning is recommended every 1 to 2 years after starting pharmacotherapy [6]. A stable or rising T-score confirms adequate response. A decline of more than 3 to 5% at the lumbar spine or more than 4 to 5% at the hip (beyond the least significant change for the machine) warrants investigation for secondary causes, medication non-adherence, or the need to switch therapy.

Bone Turnover Markers

Serum CTX (C-terminal telopeptide) and P1NP (procollagen type 1 N-terminal propeptide) can confirm drug effect within 3 to 6 months, much faster than DEXA. A drop in CTX below 0.200 ng/mL on bisphosphonate or denosumab therapy suggests adequate suppression of bone resorption [8]. These markers are especially useful for assessing adherence to oral bisphosphonates, where GI absorption varies.

Lab Work at Baseline

Before starting any osteoporosis drug, check: serum calcium, 25-OH vitamin D, creatinine/eGFR, CBC, TSH, and consider PTH if hypercalcemia or renal impairment is present. Secondary causes of bone loss (hyperparathyroidism, celiac disease, multiple myeloma, hyperthyroidism) must be excluded or treated concurrently.

Who Should Not Use Certain Medications

No drug fits every patient. Contraindications and relative cautions vary by class.

Bisphosphonate Contraindications

Oral bisphosphonates are contraindicated in patients with esophageal disorders (stricture, achalasia, inability to sit upright for 30 to 60 minutes) and in patients with eGFR <30 to 35 mL/min [8]. Zoledronic acid is contraindicated at eGFR <35 mL/min. All bisphosphonates should be avoided in patients with hypocalcemia until calcium levels are corrected.

Denosumab Considerations

Hypocalcemia must be corrected before starting denosumab. Patients with severe renal impairment are at higher risk for hypocalcemia on denosumab and need close monitoring. As noted above, stopping denosumab without a bisphosphonate bridge is dangerous.

Romosozumab Cardiovascular Warning

Romosozumab carries a boxed warning for potential increased risk of MI, stroke, and cardiovascular death. It should not be prescribed to patients with a cardiovascular event in the prior 12 months, and clinicians should weigh cardiovascular risk factors carefully before initiating treatment [21].

Teriparatide and Abaloparatide Restrictions

Both carry warnings against use in patients at increased risk for osteosarcoma: those with Paget's disease, unexplained alkaline phosphatase elevation, prior radiation to the skeleton, open epiphyses (children/adolescents), or pre-existing hypercalcemia. Treatment duration is limited to 24 months [18][19].

Special Populations

Premenopausal Women

Osteoporosis in premenopausal women is uncommon and usually secondary to glucocorticoid use, eating disorders, hypogonadism, or genetic conditions like osteogenesis imperfecta. DEXA interpretation differs: Z-scores (age-matched) are used instead of T-scores. A Z-score of −2.0 or below is considered "below expected range for age" [1]. Bisphosphonates cross the placenta and have a long skeletal half-life, so pregnancy planning must factor into treatment decisions.

Men with Osteoporosis

Men account for roughly 30% of hip fractures worldwide [3]. Testosterone replacement may improve BMD in men with documented hypogonadism, but it is not sufficient as sole therapy for osteoporosis with high fracture risk. Alendronate, risedronate, zoledronic acid, denosumab, and teriparatide are all FDA-approved for male osteoporosis [8].

Glucocorticoid-Induced Osteoporosis

The ACR 2022 guideline recommends fracture risk assessment within 6 months of starting glucocorticoids at ≥2.5 mg prednisone daily for ≥3 months [9]. Oral bisphosphonates are first-line. For patients at very high risk (prior fracture, T-score <−2.5, or high-dose steroids ≥30 mg/day), teriparatide or denosumab may be preferred as initial therapy.

Emerging Therapies and Pipeline

Several investigational agents are in late-stage development. Setrusumab, an anti-sclerostin antibody initially developed for osteogenesis imperfecta, is in Phase 3 trials. Lasofoxifene, a selective estrogen receptor modulator, has shown bone-protective effects alongside breast cancer risk reduction in preclinical extension analyses. Oral PTH analogs are also under investigation to replace the current injectable-only delivery of teriparatide [27].

The field is moving toward earlier, more aggressive treatment of very-high-risk patients, with anabolic-first sequencing becoming standard of care rather than a last resort.

Putting It All Together: A Treatment Algorithm

Moderate risk (T-score −1.5 to −2.5, FRAX above threshold, no prior fracture): Start oral bisphosphonate plus calcium/vitamin D. Reassess with DEXA at 2 years.

High risk (T-score ≤−2.5 or prior fragility fracture): Consider oral or IV bisphosphonate or denosumab. Check bone turnover markers at 3 to 6 months. Repeat DEXA at 1 to 2 years.

Very high risk (T-score ≤−3.0, multiple fractures, fracture on bisphosphonate, glucocorticoid-induced): Start anabolic therapy (romosozumab 12 months or teriparatide/abaloparatide 24 months), then transition to antiresorptive. This sequence maximizes BMD gain and fracture reduction.

The first DEXA after age 65 (or earlier with risk factors) should not be the last. Repeat testing at the intervals your clinician recommends, and do not stop therapy without a plan for what comes next. An untreated patient with a T-score of −3.0 has a 1-in-5 chance of hip fracture in the next 10 years [5].