Home Heart and Cardiovascular Health Low Testosterone and Heart Health: What We Know and What We Don’t

Low Testosterone and Heart Health: What We Know and What We Don’t

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Low testosterone is linked with heart risk, but cause and effect are complex. Learn what TRAVERSE showed, TRT safety concerns, monitoring needs, and key unknowns.

Low testosterone and heart disease often occur in the same men, but that does not mean one simply causes the other. Testosterone levels can fall with aging, obesity, diabetes, sleep apnea, chronic illness, and poor overall health—many of the same factors that raise cardiovascular risk. As a result, low testosterone can be both a hormone problem and a marker of broader metabolic health.

Testosterone replacement therapy, or TRT, has also carried years of cardiovascular controversy. The strongest recent randomized evidence is reassuring about major heart attacks and strokes when TRT is prescribed to appropriately selected men with confirmed hypogonadism and monitored carefully. However, that does not make testosterone a heart-protection drug. Therapy can raise hematocrit and blood pressure, and some studies have raised questions about atrial fibrillation, kidney events, and blood clots in certain patients.

The practical takeaway is balanced: diagnose true testosterone deficiency correctly, treat symptoms when benefits outweigh risks, and manage cardiovascular risk factors directly. Do not use testosterone simply to improve energy, muscle, or heart health without a proper diagnosis and monitoring plan.

Table of Contents

How Low Testosterone and Heart Risk Are Connected

Men with low testosterone often have higher cardiovascular risk, but much of that relationship overlaps with obesity, diabetes, aging, chronic illness, and other health conditions. This makes cause and effect difficult to separate.

Testosterone is produced mainly by the testes under signals from the pituitary gland and hypothalamus. Levels vary by time of day, age, body composition, sleep, illness, and medication use. A single low test does not prove hypogonadism.

Low testosterone is commonly seen in men with:

  • obesity, especially visceral or abdominal fat;
  • type 2 diabetes and insulin resistance;
  • obstructive sleep apnea;
  • chronic kidney, liver, or inflammatory disease;
  • opioid use;
  • pituitary or testicular disease;
  • severe acute illness;
  • older age.

Many of these conditions independently raise the risk of coronary artery disease, stroke, heart failure, and atrial fibrillation. That is why an observational study can find that men with low testosterone have more cardiovascular events without proving that raising testosterone will prevent those events.

Low testosterone can be a health signal

In some men, a low level is a clue that broader metabolic health needs attention. Excess body fat can suppress the hormone signaling that supports testosterone production, while low testosterone may in turn make it harder to maintain muscle and favorable body composition. The relationship can become circular.

That means a low result should prompt a thoughtful evaluation rather than an automatic prescription. Blood pressure, lipids, blood sugar, weight, sleep, smoking, physical activity, and family history often deserve attention at the same time.

If your main concern is cardiovascular risk, tracking blood pressure, lipids, and other heart-health numbers is usually more actionable than focusing on testosterone alone.

Does Low Testosterone Cause Heart Disease?

Low testosterone is associated with cardiovascular disease, but current evidence does not establish that testosterone deficiency is a major direct cause of atherosclerosis in the same way high LDL cholesterol, smoking, or high blood pressure are.

Several biologic links are plausible. Testosterone affects body composition, insulin action, vascular function, inflammation, red blood cell production, and muscle mass. Very low testosterone can be associated with increased fat mass and reduced lean mass. But plausible biology is not the same as proof that replacing testosterone prevents cardiovascular events.

The strongest causal evidence in cardiovascular medicine usually comes from randomized trials showing that changing a factor changes outcomes. For LDL cholesterol, that evidence is extensive: lowering ApoB-containing lipoproteins reduces heart attacks and strokes. For testosterone, the evidence is more complicated.

Observational studies can be especially misleading because illness itself lowers testosterone. A man with obesity, diabetes, untreated sleep apnea, and chronic inflammation may have a low testosterone level because of those conditions. Those same conditions may explain much of his cardiovascular risk.

Do not use testosterone as a cardiovascular prevention strategy

TRT may be appropriate for symptomatic hypogonadism, but it is not a substitute for proven cardiovascular prevention. It should not replace:

  • LDL- or ApoB-lowering treatment when indicated;
  • blood-pressure control;
  • diabetes treatment;
  • smoking cessation;
  • physical activity;
  • sleep apnea treatment;
  • weight management when excess body fat is present.

Someone can have a normal testosterone level and high cardiovascular risk, or low testosterone and relatively low risk. The hormone result is one part of the picture.

What the TRAVERSE Trial Changed

The TRAVERSE trial provided the strongest reassurance to date that properly prescribed testosterone did not increase major adverse cardiovascular events in men with confirmed hypogonadism who already had cardiovascular disease or were at high risk.

TRAVERSE enrolled 5,246 men ages 45 to 80 who had symptoms of hypogonadism, two fasting testosterone levels below 300 ng/dL, and either existing cardiovascular disease or high cardiovascular risk. Participants received transdermal testosterone gel or placebo and were followed for about 33 months on average.

The primary endpoint—cardiovascular death, nonfatal heart attack, or nonfatal stroke—occurred in 7.0% of men assigned to testosterone and 7.3% assigned to placebo. Testosterone met the trial’s criterion for cardiovascular noninferiority.

That finding matters because earlier studies and regulatory warnings had left substantial uncertainty about heart attack and stroke risk.

What TRAVERSE did not prove

TRAVERSE did not show that testosterone prevents cardiovascular disease. The trial was designed to test whether treatment was unacceptably worse than placebo for major cardiovascular events, not whether TRT should be prescribed to improve heart health.

It also studied a specific population and treatment approach: men with symptoms and confirmed low testosterone using titrated transdermal gel. The results should not be automatically extended to bodybuilding doses, anabolic steroid misuse, unmonitored injections, or men with normal testosterone who take TRT for performance or anti-aging purposes.

Importantly, TRAVERSE observed higher rates of atrial fibrillation, acute kidney injury, and pulmonary embolism in the testosterone group. These were secondary findings and require context, but they reinforce the need for individualized prescribing and monitoring.

The broader evidence is consistent with this overall picture. A 2022 individual-patient-data meta-analysis and a 2024 updated meta-analysis did not find a clear increase in major cardiovascular events with appropriately prescribed testosterone in men with hypogonadism, while also emphasizing limits in long-term data.

Cardiovascular Risks and Monitoring With Testosterone Therapy

The main cardiovascular safety issues with testosterone are not limited to heart attack and stroke. Blood pressure, hematocrit, fluid status, rhythm symptoms, and clot risk also matter.

Blood pressure can rise

Postmarketing ambulatory blood-pressure studies led the FDA to require class-wide warnings that testosterone products can increase blood pressure. Even a modest chronic rise in pressure matters because hypertension is a major cause of heart disease and stroke.

If you use TRT, blood pressure should be checked periodically. Men with uncontrolled hypertension need particular caution. A home monitor can be useful when treatment is started or adjusted. If you are unsure what your numbers mean, see normal blood pressure ranges and interpretation.

Hematocrit can rise

Testosterone stimulates red blood cell production. This can help men who are anemic, but it can also cause erythrocytosis—an excessive rise in red blood cell concentration. Hematocrit that becomes too high can increase blood viscosity and may contribute to thrombotic risk.

Clinicians generally measure hematocrit before therapy and again during treatment. If it rises excessively, treatment may need to be paused, reduced, or changed while the cause is evaluated. Untreated sleep apnea, smoking, dehydration, and high altitude can also affect hematocrit.

Blood clots and pulmonary embolism

The relationship between TRT and venous thromboembolism remains an area of monitoring and debate. TRAVERSE observed more pulmonary embolism in the testosterone group. A personal history of unexplained blood clots or known thrombophilia should be discussed before therapy.

Seek urgent care for sudden unexplained shortness of breath, chest pain that worsens with breathing, coughing blood, or one-sided leg swelling.

Atrial fibrillation and palpitations

TRAVERSE also found a higher incidence of atrial fibrillation with testosterone. It is not yet clear how broadly this finding applies or whether it represents a consistent class effect across all treatment settings.

New sustained palpitations, an irregular pulse, fainting, or unexplained shortness of breath during TRT should be evaluated rather than dismissed as a harmless side effect. For background on common triggers and symptoms, see atrial fibrillation symptoms and warning signs.

Fluid retention and heart failure

Androgens can promote sodium and water retention in some people. Men with significant heart failure or edema require careful assessment before and during treatment. Rapid weight gain, worsening leg swelling, or increasing shortness of breath should prompt medical review.

Who Should Be Tested for Low Testosterone?

Testing is most useful when a man has symptoms or signs consistent with testosterone deficiency, not as routine screening for everyone. Diagnosis generally requires both compatible symptoms and repeatedly low morning testosterone values.

Symptoms can include:

  • reduced libido;
  • fewer spontaneous or morning erections;
  • erectile dysfunction in some cases;
  • reduced energy;
  • loss of muscle mass or strength;
  • low bone density or fractures;
  • infertility;
  • hot flashes in severe deficiency;
  • depressed mood or reduced motivation, although these are nonspecific.

One low result is not enough

Testosterone follows a daily rhythm and is usually highest in the morning. Acute illness, poor sleep, calorie restriction, and recent medication changes can temporarily lower it. For that reason, diagnosis commonly relies on at least two morning measurements obtained on separate days under appropriate conditions.

The exact laboratory threshold varies somewhat by guideline and assay. Many U.S. practices use around 300 ng/dL as an important cutoff, while some European guidance uses 12 nmol/L, about 346 ng/dL, in the right clinical context. Numbers should be interpreted with symptoms, assay quality, and sometimes free testosterone or sex hormone-binding globulin.

Additional testing can include luteinizing hormone, follicle-stimulating hormone, prolactin, iron studies, pituitary evaluation, or other tests to determine whether the problem is testicular, pituitary/hypothalamic, medication-related, or functional.

Fertility changes the decision

Exogenous testosterone suppresses the hormonal signals that drive sperm production and can markedly reduce fertility. Men who want to preserve fertility should discuss alternatives with an endocrinologist, urologist, or reproductive specialist before starting TRT.

Lifestyle, Weight, Sleep, and Metabolic Health

For men with obesity, poor sleep, or metabolic disease, improving overall health can sometimes raise testosterone while directly lowering cardiovascular risk. This is especially relevant when the low level is functional rather than caused by permanent testicular or pituitary damage.

Weight loss can help

Excess visceral fat is strongly linked to lower testosterone. In men with obesity, meaningful weight loss often raises endogenous testosterone while improving blood pressure, triglycerides, glucose control, sleep apnea severity, and mobility.

That does not mean every man can “diet his way out” of true hypogonadism. Men with primary testicular failure or pituitary disease may still need hormone treatment. But weight management is an important part of the cardiovascular plan when excess body fat is present. The guide to visceral fat and heart risk explains why abdominal fat matters metabolically.

Exercise improves risk even without a large testosterone change

Resistance training helps preserve muscle and strength, while aerobic exercise improves fitness, blood pressure, insulin sensitivity, and cardiovascular risk. Exercise may modestly influence testosterone depending on body composition, training status, and energy balance, but its cardiovascular benefits do not depend on raising the hormone.

Treat sleep apnea

Obstructive sleep apnea is associated with metabolic dysfunction and can coexist with low testosterone. Untreated severe sleep apnea also complicates TRT because testosterone can worsen breathing-related sleep problems in some patients and sleep apnea can contribute to elevated hematocrit.

Avoid “testosterone boosters” and anabolic steroid cycles

Over-the-counter testosterone boosters are often poorly supported by evidence, and some may contain undeclared or pharmacologically active ingredients. Supraphysiologic anabolic steroid use is a different exposure from medically supervised TRT and is associated with adverse lipid changes, hypertension, cardiomyopathy, arrhythmias, thrombosis, and other harms.

A prescription that restores a deficient man into a physiologic range should not be equated with bodybuilding doses that push androgen levels far above normal.

Treat reversible contributors before assuming testosterone is the main problem

Obesity, untreated sleep apnea, poor sleep, heavy alcohol use, severe illness, some opioid medicines, and certain pituitary or testicular disorders can contribute to low testosterone. Addressing a reversible cause may improve both testosterone and cardiovascular risk at the same time. For example, weight loss can improve blood pressure, insulin resistance, sleep apnea severity, and testosterone in some men, making it more useful than treating the laboratory value in isolation.

If testosterone therapy is started, monitoring is part of the treatment rather than an optional extra. Clinicians commonly follow symptoms, testosterone level, hematocrit or hemoglobin, and blood pressure, with additional monitoring based on age and prostate risk. A rising hematocrit matters because excessive red-cell concentration can increase blood viscosity and may require dose adjustment or interruption. New leg swelling, sudden shortness of breath, chest pain, palpitations, or neurologic symptoms need prompt medical assessment rather than waiting for the next routine visit.

Men who want future fertility should also discuss that goal before treatment. External testosterone can suppress sperm production. This issue is separate from heart safety, but it can substantially change the best treatment choice and is easy to miss when attention is focused only on testosterone levels.

What We Still Do Not Know

The biggest remaining questions involve very long-term cardiovascular outcomes, differences among formulations and dosing strategies, and which subgroups are most vulnerable to specific adverse effects.

TRAVERSE substantially reduced uncertainty about major cardiovascular events over several years, but many men use testosterone for much longer. Long-term randomized data extending a decade or more are limited.

Questions that remain include:

  • whether different injections, gels, pellets, and oral formulations carry meaningfully different cardiovascular risks;
  • how much treatment-related blood-pressure elevation matters over many years;
  • whether the atrial fibrillation and pulmonary embolism signals seen in TRAVERSE will be confirmed in other datasets;
  • which men are most likely to develop clinically important erythrocytosis;
  • whether treating functional low testosterone related to obesity produces the same risk-benefit balance as treating clear pituitary or testicular disease;
  • how best to individualize treatment in men with established coronary disease, heart failure, prior clots, or arrhythmias.

Regulatory guidance has changed as evidence has evolved. In 2025 the FDA removed older boxed-warning language about increased major cardiovascular events after reviewing TRAVERSE, while adding class-wide blood-pressure warnings. Further labeling updates occurred in 2026 as the agency continued to reassess testosterone use and indications. The direction of travel is important: safety recommendations are becoming more evidence-based, but they still require careful diagnosis and monitoring.

For a man with confirmed symptomatic hypogonadism, the current evidence is more reassuring than it was a decade ago. For a man with normal testosterone looking for a heart-health, anti-aging, or performance shortcut, the evidence does not support TRT as a cardiovascular strategy.

The practical approach is straightforward: confirm the diagnosis, treat symptoms rather than a number, monitor blood pressure and hematocrit, watch for rhythm or clot symptoms, and manage established cardiovascular risks directly.

The formulation and dose also matter. Injections, gels, patches, and other preparations can produce different peaks, troughs, skin-transfer concerns, and effects on hematocrit. The goal of replacement is usually to restore testosterone into a physiologic range while improving symptoms—not to push levels above normal. Higher doses used for bodybuilding are a different exposure and should not be assumed to have the same safety profile as medically supervised replacement. When symptoms fail to improve despite a confirmed normal treatment level, the diagnosis and treatment plan should be reassessed instead of automatically escalating the dose.

References

Disclaimer

This article is for general education and does not replace individualized medical care. Testosterone therapy should be used only after an appropriate evaluation confirms deficiency and the potential benefits and risks are discussed. Seek urgent care for chest pain, severe shortness of breath, fainting, or symptoms of a possible blood clot.

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