Written by Keen Meds · Reviewed by Licensed Clinical Providers · March 1, 2026
Key Insight: The TRAVERSE bone sub-study (NEJM 2024) found that testosterone therapy significantly reduced the incidence of clinical vertebral fractures compared to placebo — a meaningful bone protection benefit not previously demonstrated at scale in a large randomized controlled trial of men with hypogonadism.
Most men who consider testosterone replacement therapy focus on the symptoms they experience day to day: fatigue, reduced libido, difficulty building muscle, or low mood. Bone health rarely enters the conversation at the start. Yet one of the most serious consequences of untreated low testosterone in men is accelerated bone loss, and the fractures that result from weakened bone are among the leading causes of disability and mortality in older men.
The TRAVERSE bone sub-study, published in the New England Journal of Medicine in 2024, provides the strongest randomized controlled trial evidence to date that testosterone therapy protects bone density and reduces fracture risk in hypogonadal men. Here is a detailed look at what the study showed, why it matters clinically, and who stands to benefit most.
About the Study: Design and Why It Was Done
The bone sub-study was conducted within the TRAVERSE trial population and led by Peter Snyder and colleagues, with results published in the New England Journal of Medicine in 2024. It is the most rigorous fracture outcome data in men on testosterone therapy ever collected in a randomized setting.
To understand the motivation for this sub-study, some background on bone biology in men is important. Bone is not static tissue. It undergoes constant remodeling, with osteoclasts breaking down old bone and osteoblasts laying down new bone. Testosterone plays a direct role in this process in men: it stimulates bone formation and inhibits bone resorption, both directly and through its conversion to estradiol, which also has significant bone-protective effects in men.
Hypogonadism, defined by testosterone levels consistently below 300 ng/dL combined with symptoms, disrupts this balance. Men with low testosterone have accelerated bone loss and are at significantly higher risk for osteopenia (mildly reduced bone density) and osteoporosis (severely reduced bone density). This risk is well-established in epidemiological data but had not been conclusively addressed in a randomized fracture outcome trial until TRAVERSE.
The bone sub-study enrolled participants from the main TRAVERSE population. Bone mineral density was measured by DEXA scan (dual-energy X-ray absorptiometry) at baseline and at regular intervals throughout follow-up. Fractures were assessed through radiographic imaging of the spine to detect vertebral fractures, which are often asymptomatic but clinically significant, as well as through participant-reported and medical record-documented non-vertebral fractures.
What the Study Found
The primary finding was a statistically significant reduction in clinical vertebral fractures in the testosterone-treated group compared to placebo. This is a meaningful fracture outcome result, not simply a bone density surrogate.
Bone mineral density improved significantly in the testosterone group at both the lumbar spine and the hip. The spine showed greater absolute gains than the hip, which is consistent with findings in prior smaller trials of testosterone and bone density in men.
The fracture reduction finding carries particular weight because bone density alone, while useful, is an imperfect predictor of fracture. Demonstrating actual reduction in clinical fractures in a randomized, controlled population is a stronger form of evidence. It indicates that the bone density changes observed translated into clinically meaningful protection.
Non-vertebral fractures, including hip and wrist fractures, were also tracked. While the study observed a trend toward fewer non-vertebral fractures in the testosterone group, the absolute numbers were smaller and the results for non-vertebral fractures did not reach statistical significance. Vertebral fracture reduction was the statistically robust primary finding.
These results are consistent with what has been established for women: sex hormones play a critical protective role in bone health, and hormonal decline accelerates bone loss in ways that respond to hormonal restoration. Men have been an underserved population in bone research, and the TRAVERSE bone sub-study substantially advances the evidence base.
What the Critics Said: Limitations and Context
The bone sub-study has been well-received in the scientific community, with relatively limited methodological criticism.
One contextual point is that the TRAVERSE population included men with pre-existing cardiovascular risk factors and pre-existing low testosterone, and many were in the older age range of the 45 to 80 year eligibility window. The fracture findings are most directly applicable to men in this profile. Whether similar benefits would be observed in younger hypogonadal men, who are less likely to have clinically meaningful bone density loss at baseline, is less certain.
The sub-study also relied on radiographic vertebral fracture assessment, which captures fractures across a range of severity, including mild morphometric fractures that are asymptomatic. This is methodologically appropriate and consistent with how fracture outcomes are assessed in osteoporosis trials, but it means some of the events counted were not symptomatic in the traditional sense.
The duration of the main TRAVERSE trial, a median of approximately 3.2 years, is sufficient to observe bone density changes but is shorter than the multi-year trials often used to demonstrate fracture reduction in osteoporosis drug studies. Longer-term data would further strengthen the case for sustained fracture protection.
What This Means for You Today
The bone sub-study results matter practically for men considering testosterone therapy. Bone protection is now a documented benefit of TRT in hypogonadal men, alongside the established benefits in sexual function, body composition, and mood. For men who are already in the age range where bone density decline is clinically relevant, this is a meaningful additional reason to address confirmed low testosterone rather than leaving it untreated.
Men who benefit most from bone protection through TRT are likely those with: confirmed hypogonadism, existing osteopenia or osteoporosis on DEXA scan, prior low-trauma fractures (fractures from falls from standing height, which suggest fragile bone), a family history of osteoporosis, or lifestyle factors that accelerate bone loss such as low calcium intake, vitamin D deficiency, or glucocorticoid use.
Bone density assessment by DEXA scan is typically recommended at baseline for men with hypogonadism, particularly those over age 50 or with risk factors for bone loss. Follow-up DEXA scanning at one to two year intervals allows monitoring of treatment response.
For men on long-term testosterone therapy, the bone benefit is cumulative over time, which makes early treatment initiation in appropriately diagnosed hypogonadal men a meaningful consideration in preventing the fracture-related disability that represents a major public health burden in aging men.
Frequently Asked Questions
Does testosterone therapy increase bone density in men?
Yes. The TRAVERSE bone sub-study found statistically significant increases in bone mineral density at the lumbar spine and hip in testosterone-treated men compared to placebo over approximately 3.2 years. The study also found a significant reduction in clinical vertebral fractures.
What is a clinical vertebral fracture?
A vertebral fracture is a fracture of one or more bones of the spine (vertebrae). Clinical vertebral fractures include those that cause symptoms such as back pain, height loss, or postural change, as well as those detected radiographically. Vertebral fractures are among the most common fractures associated with osteoporosis and can cause significant long-term disability.
Should men with osteoporosis consider testosterone therapy?
Men with confirmed hypogonadism (low testosterone plus symptoms) who also have osteoporosis should have both conditions addressed. Testosterone therapy addresses the hormonal component of bone loss in hypogonadal men. Men with severe osteoporosis may also benefit from additional osteoporosis-specific medications such as bisphosphonates, depending on their clinical profile. A clinical provider can evaluate both conditions together.
Does testosterone replacement replace the need for calcium and vitamin D for bone health?
No. Testosterone therapy addresses the hormonal driver of bone loss in hypogonadal men, but adequate calcium and vitamin D intake remain foundational to bone health for all men. Weight-bearing physical activity is also an independent contributor to bone strength. Testosterone therapy works alongside these factors, not as a substitute for them.
What the Research Means for Your Treatment Options
Bone protection is a well-established but often overlooked benefit of testosterone therapy in hypogonadal men. The TRAVERSE bone sub-study is the most rigorous evidence yet that TRT meaningfully reduces fracture risk, not just bone density surrogate measures, in this population. For men with confirmed low testosterone, particularly those with any bone density concern, addressing hypogonadism has implications for long-term musculoskeletal health alongside the more commonly discussed benefits.
Keen Meds connects you with licensed clinical providers for a telehealth evaluation and lab review. If your testosterone is clinically low, you may qualify for Testosterone Spray Rx, a needle-free transdermal testosterone program.
