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Hormones & Men's HealthTestosterone Therapy and Your Heart: What the TRAVERSE Trial Changed
The largest randomized trial of testosterone therapy found no increase in heart attacks or strokes in men with low testosterone. It also found risks men should know about.
Key takeaways
- In more than 5,200 men with low testosterone and elevated heart risk, testosterone therapy did not increase major cardiovascular events compared with placebo.
- The testosterone group had higher rates of atrial fibrillation, acute kidney injury and pulmonary embolism.
- Low testosterone should be confirmed with repeated morning blood tests plus symptoms before treatment.
- Testosterone therapy suppresses sperm production, which matters for anyone hoping to have children.
For more than a decade, a cloud hung over testosterone replacement therapy (TRT): did it raise the risk of heart attack and stroke? A few observational studies suggested it might, and regulators added warnings. The TRAVERSE trial was designed to settle the question.
What the trial did
TRAVERSE, published in the New England Journal of Medicine in 2023, enrolled 5,246 men aged 45 to 80 who had symptoms of hypogonadism, low testosterone levels, and either existing cardiovascular disease or a high risk of it. They were randomly assigned to a daily testosterone gel or a placebo gel and followed for an average of about two years.
What it found
Major adverse cardiac events (cardiovascular death, nonfatal heart attack or nonfatal stroke) occurred in 7.0% of the testosterone group and 7.3% of the placebo group. Testosterone was “noninferior,” meaning it did not increase this risk.
But the trial also found higher rates of atrial fibrillation, acute kidney injury and pulmonary embolism in men receiving testosterone. Those are not trivial, and they are part of the conversation for men with a history of heart rhythm problems or blood clots.
What it doesn’t tell us
TRAVERSE studied men with confirmed low testosterone using doses aimed at normal levels. It says nothing about men with normal testosterone using it for performance or anti-aging, or about the high doses used for bodybuilding.
Getting the diagnosis right
Endocrine Society guidance calls for a diagnosis of hypogonadism only when a man has consistent symptoms (such as low libido, erectile dysfunction, fatigue or loss of muscle) and unequivocally low testosterone confirmed on more than one early-morning blood test. Levels fluctuate, and poor sleep, obesity, illness and some medications can lower them temporarily. Addressing those causes sometimes restores levels without treatment.
The fertility trade-off
Taking testosterone signals the brain to shut down the body’s own production, which also reduces sperm production, sometimes to zero. Men who want children in the future should discuss alternatives with a urologist or endocrinologist before starting.
Monitoring on therapy
Men on TRT need periodic blood tests, including testosterone levels, hematocrit (testosterone can thicken the blood) and, depending on age, prostate screening discussions.
Frequently asked questions
Does testosterone therapy cause heart attacks?
In the TRAVERSE trial of men with low testosterone and high cardiovascular risk, testosterone therapy did not increase heart attacks, strokes or cardiovascular death compared with placebo.
What are the risks of TRT?
TRAVERSE found higher rates of atrial fibrillation, acute kidney injury and pulmonary embolism. TRT can also raise red blood cell counts and suppress fertility.
How is low testosterone diagnosed?
Guidelines call for consistent symptoms plus low testosterone confirmed on at least two early-morning blood tests.