The latest evidence on testosterone, cardiovascular risk, and the TRAVERSE trial
For years, TRT was considered risky for the heart. New research tells a very different story. Here is what the latest evidence says about testosterone and cardiovascular health.
For more than a decade, testosterone replacement therapy carried a cloud of cardiovascular concern. Two studies published in 2010 and 2013 suggested a possible link between TRT and increased cardiovascular risk, triggering FDA warnings and causing many physicians to become reluctant to prescribe it. The medical community — and patients — were understandably cautious.
But science is self-correcting. Those early studies had significant methodological flaws, and the years since have produced far more rigorous evidence. The current picture is not just reassuring — it suggests that low testosterone itself may be the cardiovascular risk factor, not TRT.
Low testosterone is associated with a cluster of metabolic and cardiovascular risk factors:
Increased visceral fat. Testosterone plays a key role in regulating body composition. Low testosterone promotes the accumulation of visceral (abdominal) fat — the type most strongly associated with cardiovascular disease, insulin resistance, and metabolic syndrome.
Insulin resistance. Low testosterone is independently associated with insulin resistance and type 2 diabetes — both major cardiovascular risk factors.
Dyslipidemia. Men with low testosterone tend to have higher LDL cholesterol, lower HDL cholesterol, and higher triglycerides — a lipid profile associated with increased cardiovascular risk.
Endothelial dysfunction. Testosterone supports the health of the endothelium — the inner lining of blood vessels. Low testosterone is associated with impaired endothelial function, which is an early marker of atherosclerosis.
Inflammation. Low testosterone is associated with elevated inflammatory markers including C-reactive protein (CRP) and interleukin-6, both of which contribute to cardiovascular disease.
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The TRAVERSE trial, published in the New England Journal of Medicine in 2023, is the most definitive study to date on TRT and cardiovascular safety. This large, randomized controlled trial enrolled over 5,200 men with hypogonadism and cardiovascular risk factors and followed them for an average of ~33 months (nearly three years). For the broader safety picture across all monitored markers — prostate, hematocrit, liver, bone — see our long-term TRT safety post.
The conclusion: testosterone therapy did not increase the risk of major adverse cardiovascular events (heart attack, stroke, or cardiovascular death) compared to placebo. This was a landmark finding that significantly shifted the evidence base.
Earlier meta-analyses and observational studies have similarly found that TRT in men with documented hypogonadism is not associated with increased cardiovascular risk — and some suggest it may be protective, particularly for men with metabolic syndrome.
One legitimate cardiovascular consideration with TRT is the potential for elevated hematocrit — the percentage of red blood cells in the blood. Testosterone stimulates red blood cell production, and in some men, this can lead to polycythemia (too many red blood cells), which increases blood viscosity and theoretically raises clotting risk.
This is why regular lab monitoring is essential on TRT. Hematocrit should be checked at baseline and periodically during treatment. If it rises above 54%, dose adjustment or temporary cessation is warranted. This is a manageable, monitorable side effect — not a reason to avoid TRT, but a reason to do it under proper medical supervision.
The evidence increasingly suggests that low testosterone — not TRT — is the cardiovascular risk factor. Optimizing testosterone levels in men with documented hypogonadism appears to improve body composition, insulin sensitivity, lipid profiles, and endothelial function — all of which support cardiovascular health.
TRT should be done under physician supervision with regular lab monitoring. But for men with low testosterone and cardiovascular risk factors, the question may no longer be "is TRT safe for my heart?" — it may be "is leaving my testosterone low safe for my heart?"
The TRAVERSE trial (2023) — the largest randomized controlled trial on TRT and cardiovascular outcomes — found that testosterone therapy did not increase the risk of heart attack, stroke, or cardiovascular death compared to placebo.
Yes. Low testosterone is associated with increased visceral fat, insulin resistance, dyslipidemia, endothelial dysfunction, and inflammation — all of which are cardiovascular risk factors.
Hematocrit is the percentage of red blood cells in your blood. TRT can raise hematocrit, and if it gets too high (above 54%), it increases blood viscosity and clotting risk. Regular lab monitoring catches this early.
Men with a history of cardiovascular disease should discuss TRT carefully with their physician. It is not automatically contraindicated, but requires careful evaluation, monitoring, and individualized decision-making.
TRT can modestly reduce HDL (good) cholesterol in some men while improving body composition and insulin sensitivity. The net cardiovascular effect depends on the individual and should be monitored through regular labs.
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