For years, one question hung over testosterone therapy: does it raise the risk of heart attack and stroke? Smaller studies pointed in different directions. In 2023, the TRAVERSE trial gave the clearest answer so far.
What the trial did
TRAVERSE enrolled 5,246 men aged 45 to 80 who had symptoms of low testosterone, low testosterone levels on blood tests, and either existing heart disease or a high risk of it. These are the men doctors worried about most.
Half used a daily testosterone gel, with the dose adjusted to keep levels in a normal range. The other half used a placebo gel. Neither the men nor their doctors knew who was getting which.
The main result
Major heart events (a heart attack, a stroke or death from heart disease) happened in 7.0% of men on testosterone and 7.3% of men on placebo. Statistically, testosterone was "noninferior": it did not increase the risk of these events.
The trial recorded more of these events than all earlier randomized testosterone trials combined, which is why its result carries so much weight.
What was more common with testosterone
The trial also found a few problems that were more frequent in the testosterone group:
- Atrial fibrillation, an irregular heart rhythm: 3.5% vs 2.4%
- Acute kidney injury: 2.3% vs 1.5%
- Blood clots in the lung: 0.9% vs 0.5%
These differences are small, but they are real reasons to monitor anyone on testosterone, and to take a careful history before starting.
What the trial doesn't tell you
TRAVERSE studied men with confirmed low testosterone and symptoms. It does not show that testosterone is safe or useful for men whose levels are normal, or at doses above the normal range. It also wasn't designed to prove that testosterone improves energy or strength; separate studies look at those questions.
The trial was funded by a group of testosterone manufacturers. It was run as a large, placebo-controlled study and published in the New England Journal of Medicine.
What this means for you
If you have symptoms and two low early-morning testosterone results, TRAVERSE is reassuring: treatment, done properly, did not raise the risk of heart attack or stroke in men like you. "Done properly" matters. That means confirming the diagnosis, keeping levels in a normal range, and checking your labs on a schedule.
Read how we diagnose and monitor testosterone therapy, or see how at-home lab testing works.
Sources
- Lincoff AM, et al. Cardiovascular safety of testosterone-replacement therapy. N Engl J Med. 2023;389(2):107–117. doi.org/10.1056/NEJMoa2215025
- Bhasin S, et al. Testosterone therapy in men with hypogonadism: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2018;103(5):1715–1744. doi.org/10.1210/jc.2018-00229
