What TRAVERSE found, in brief
Testosterone did not raise the risk of heart attack, stroke or cardiovascular death in men who already had heart disease or were at high risk of it. That was the headline of the TRAVERSE trial, published in the New England Journal of Medicine in June 2023, and it answered a question that had hung over testosterone therapy for about a decade.
The same trial found problems that get less airtime. Men on testosterone had more atrial fibrillation, more acute kidney injury and more pulmonary embolism than men on placebo, and a later analysis found more fractures. Read together, the results say testosterone is not the heart threat many feared, and it is not free of risk either.
Who was in the trial, and what did they take?
TRAVERSE enrolled 5,246 men aged 45 to 80 across the United States. Every man reported symptoms of low testosterone, had two fasting testosterone results under 300 ng/dL, and had either existing cardiovascular disease or a high risk of it. That design put the trial squarely on the men clinicians worry about most.
Men were randomly assigned to a daily 1.62% testosterone gel or a placebo gel. Doses were adjusted to hold testosterone between 350 and 750 ng/dL, roughly mid-normal. Average time on treatment was 21.7 months while average follow-up was 33 months, so many men spent part of the study off their gel. That gap is worth remembering when you read the numbers.
Did testosterone raise heart attack and stroke risk?
No, not in this trial. The main safety endpoint combined cardiovascular death, nonfatal heart attack and nonfatal stroke. It occurred in 182 men on testosterone (7.0%) and 190 men on placebo (7.3%), a hazard ratio of 0.96 with a 95% confidence interval of 0.78 to 1.17, which passed the trial’s preset test for noninferiority.
Noninferior is a careful word. It means testosterone was not meaningfully worse than placebo for these events; it does not mean testosterone protected anyone’s heart. Each piece of the composite, and a broader endpoint that added coronary procedures, also looked similar between the two groups.
What were the trade-offs?
The trade-offs were a handful of less common harms on one side and modest symptom benefits on the other.
Which risks were higher on testosterone?
Several other events were more common with testosterone, and they now sit in the warnings on testosterone labels. The Kyzatrex label reports these TRAVERSE figures:
| Event in TRAVERSE | Testosterone gel | Placebo gel |
|---|---|---|
| Nonfatal arrhythmias needing intervention | 5.2% | 3.3% |
| Atrial fibrillation | 3.5% | 2.4% |
| Acute kidney injury | 2.3% | 1.5% |
| Bone fracture | 3.5% | 2.5% |
| All venous blood clots | 1.7% | 1.2% |
| Pulmonary embolism | 0.9% | 0.5% |
The absolute gaps are about one or two percentage points, small for any single man, yet consistent enough that regulators wrote them down. The fracture analysis published in 2024 found clinical fractures in 3.50% of the testosterone group and 2.46% of the placebo group over a median of 3.19 years. That surprised many experts, because testosterone usually raises bone density.
Did the men get anything out of it?
TRAVERSE was built to measure safety, but a nested study also asked whether treatment helped. In 1,161 men who reported low libido, the sexual function substudy found that testosterone improved sexual activity, sexual desire and general low-testosterone symptoms compared with placebo, with the effect holding at 24 months. Erectile function itself did not improve.
That pattern matters when you set expectations. Testosterone tends to help desire and drive in men whose levels are truly low, while erections depend on blood vessels and nerves as much as hormones. Men whose main concern is erections often need a separate look at vascular health and ED treatment.
What changed after TRAVERSE?
Regulators and guideline writers responded in two steps. On February 28, 2025, the FDA announced class-wide labeling changes that added TRAVERSE results to every testosterone label, removed boxed warning language about increased cardiovascular risk and added blood pressure warnings. Our review of the 2025 FDA testosterone label changes covers that action in full.
In July 2026 the Endocrine Society summarized TRAVERSE as showing no meaningful increase in heart attack and stroke over one to four years, while flagging roughly a 50% relative increase in pulmonary embolism and more fractures. The Society also restated that diagnosis rests on symptoms plus consistently low, accurately measured testosterone.
What TRAVERSE means for monitoring on TRT
For a man on testosterone, the heart attack worry has shrunk while a short list of specific risks deserves routine attention. Each one maps to something a careful plan already checks.
- Heart rhythm. Report palpitations, a racing or irregular pulse, or new breathlessness on exertion. Our answer on whether TRT can cause atrial fibrillation explains what is known.
- Kidneys. A baseline creatinine and eGFR gives a reference point if kidney function dips later. The eGFR and creatinine test page explains both numbers.
- Blood clots. Learn the signs of a leg clot and a lung clot, listed on our page about blood clot warning signs on TRT.
- Red blood cells. Hematocrit tends to climb on testosterone and is checked on a schedule; see hematocrit testing for men.
- Blood pressure and bones. Home readings and attention to falls round out the list.
Sudden chest pain, sudden shortness of breath, coughing up blood or a swollen, painful calf are emergencies. Call 911 or go to the nearest emergency room instead of waiting for a clinic visit.
One limit applies to every figure here. TRAVERSE tested a daily gel in men 45 and older with heart risk, followed for about three years. Injections, pellets and younger men were outside its design, and nobody has ten-year data yet.
How Ultimate Male applies the TRAVERSE findings
At our San Gabriel and Downey clinics, an evaluation for testosterone therapy begins with your heart history, current medicines, blood pressure and baseline labs, drawn on site with results usually back in 24 to 48 hours. A PA-C or MD goes through them with you one-on-one. The visit is an evaluation, not a promise of treatment.
If you do start, follow-up visits and labs are part of the plan, and TRAVERSE gives you good reasons to ask about rhythm symptoms, kidney function and hematocrit at each one. Men with established heart disease can read our page for men with heart disease, and anyone weighing the wider debate may like our look at TRT myths checked against the evidence. The free 10-minute phone call is the simplest way to start.
