Testosterone and Heart Health in Men: What the Evidence Says

The relationship between testosterone and heart health is one of the most debated topics in men’s medicine, and for good reason: for nearly a decade, men considering testosterone replacement therapy (TRT) heard conflicting messages about whether it might harm their hearts. The short answer the current evidence supports is reassuring but nuanced. The largest randomized trial to date, TRAVERSE, found that properly prescribed testosterone therapy did not increase major adverse cardiac events compared with placebo in men with low testosterone and existing cardiovascular risk (1). At the same time, low testosterone itself appears closely tied to the very metabolic problems that drive heart disease. Understanding both sides of this picture helps men make informed decisions with their clinicians.

How Low Testosterone Relates to Cardiometabolic Health

Before discussing therapy, it helps to understand why testosterone and heart health are linked in the first place. Low testosterone rarely travels alone. Research consistently shows associations between low T and a cluster of cardiometabolic risk factors, including abdominal obesity, insulin resistance, type 2 diabetes, and unfavorable cholesterol and inflammatory profiles (2).

This overlap is part of why men with low testosterone often have higher rates of metabolic syndrome. The direction of cause and effect is not fully settled, though. Excess body fat can lower testosterone (in part because fat tissue converts testosterone to estrogen), and low testosterone may in turn make it harder to maintain lean muscle and a healthy metabolism. The picture is likely bidirectional, with each factor reinforcing the other.

What this means practically: a low testosterone reading may be a useful signal. It is not a diagnosis of heart disease, but it can prompt a broader look at a man’s metabolic health, blood pressure, lipids, blood sugar, and body composition. For many men, addressing those underlying drivers, through weight management, exercise, sleep, and standard cardiac care, matters as much as any hormone decision. If you are noticing fatigue, low libido, or loss of muscle, the signs of low testosterone in men are worth reviewing alongside a full lab panel.

The Historical Safety Controversy

The worry about testosterone and cardiovascular harm did not appear out of nowhere. Around 2013 and 2014, a few observational studies and one trial in older men with limited mobility raised the possibility that TRT might increase cardiac events. The coverage was alarming, and in 2015 the U.S. Food and Drug Administration required a label warning about a possible cardiovascular risk while calling for more research.

Those early signals had real limitations. Some studies were observational and prone to confounding, meaning the men who received testosterone may have differed in important ways from those who did not. Others were small or measured outcomes that were hard to interpret. The result was genuine uncertainty rather than a clear answer, and the field needed a large, well-designed randomized controlled trial to resolve it. That is precisely what regulators eventually required, and that is what TRAVERSE was built to provide.

What the TRAVERSE Trial Found About TRT and Cardiovascular Risk

TRAVERSE (Lincoff et al., published in the New England Journal of Medicine in 2023) is the most important study yet on TRT cardiovascular risk. It enrolled more than 5,000 men aged 45 to 80 who had two low morning testosterone measurements, symptoms of hypogonadism, and either existing cardiovascular disease or a high risk of it. Participants were randomly assigned to a daily testosterone gel or a placebo gel and followed for an average of roughly two to three years (1).

The primary safety question was whether testosterone increased major adverse cardiac events, a composite of cardiovascular death, nonfatal heart attack, and nonfatal stroke. The result: testosterone was non-inferior to placebo, meaning the trial did not find that TRT increased the rate of these major events in this higher-risk population (1). For a treatment that had carried a cloud of suspicion for a decade, this was a meaningful and reassuring finding.

The nuance matters, though, and responsible reading of the data requires it. TRAVERSE also observed somewhat higher rates of a few specific events in the testosterone group, including atrial fibrillation (an irregular heart rhythm), pulmonary embolism (a blood clot in the lungs), and acute kidney injury (1). These were secondary findings and should be interpreted cautiously, but they are not nothing. They suggest that while testosterone did not raise the headline cardiac risk, it is not free of cardiovascular considerations, and certain men may warrant extra attention.

It is also worth noting what TRAVERSE was and was not designed to do. It tested a specific testosterone gel at therapeutic doses in men with diagnosed deficiency. It was not a study of high-dose testosterone, supraphysiologic use, or treatment of men with normal levels. The findings apply to legitimate medical therapy for genuine hypogonadism, which is exactly the context in which TRT belongs.

Why Proper Diagnosis, Dosing, and Monitoring Matter

The TRAVERSE results should not be read as a green light for testosterone in everyone. They are reassuring specifically because the men studied had confirmed low testosterone and were treated to a target range under medical supervision. The safety of any hormone therapy depends heavily on doing it correctly.

Proper diagnosis comes first. Endocrine Society guidance recommends diagnosing hypogonadism only in men with both consistent symptoms and unequivocally low testosterone confirmed on more than one morning blood test, since levels fluctuate and a single reading can mislead (2). Treating a number without symptoms, or chasing peak performance levels, is not the same as treating a medical condition.

Dosing and monitoring come next. One of the clearest, most consistent effects of testosterone therapy is a rise in hematocrit, the proportion of red blood cells in the blood. If hematocrit climbs too high, blood can thicken, which is why guidelines recommend checking it at baseline and during treatment and adjusting or pausing therapy if it rises excessively (2). Clinicians also typically monitor testosterone levels to keep them in a healthy range rather than overshooting, and they assess prostate health where appropriate. Understanding the full range of TRT side effects and how monitoring catches them early is part of doing therapy responsibly.

For men with existing heart disease, the calculus is individualized. Stable cardiovascular disease is not automatically a reason to avoid treatment, but recent unstable events generally are, and the modest atrial fibrillation and clot signals from TRAVERSE are reasons to personalize the decision. This is where an experienced clinician and honest shared decision-making make the difference.

The Bottom Line on Testosterone and Heart Health

Pulling it together: low testosterone is consistently associated with cardiometabolic risk, but that association does not mean testosterone therapy is either a cause of heart disease or a cure for it. The historical fear that TRT broadly raises cardiac risk was not confirmed by TRAVERSE, the largest randomized trial designed to answer the question, which found no increase in major adverse cardiac events versus placebo in higher-risk men (1). The hedged signals around atrial fibrillation and pulmonary embolism keep this from being a blanket all-clear, and they reinforce why diagnosis, dosing, and monitoring are not optional details but the core of safe care.

For men weighing their options, the practical path is straightforward: get an accurate diagnosis, address underlying metabolic health, and if therapy is appropriate, pursue it with proper lab monitoring. Our team can help you evaluate whether testosterone therapy fits your situation as part of a broader hormone therapy and longevity plan.

If you are in Miami and want a clear, evidence-based look at your testosterone and overall cardiometabolic health, our clinicians are happy to walk through your labs and goals with you. Reach out to schedule a TRT consult at Rewind Anti-Aging of Miami.

Sources

1. Lincoff AM, Bhasin S, Flevaris P, et al. Cardiovascular Safety of Testosterone-Replacement Therapy (TRAVERSE). New England Journal of Medicine. 2023;389(2):107-117.
2. Bhasin S, Brito JP, Cunningham GR, et al. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline. Journal of Clinical Endocrinology & Metabolism. 2018;103(5):1715-1744.

This article is for general educational purposes and is not medical advice; consult a qualified clinician about your individual health.