Is TRT Safe for Your Heart? What the Research Shows
Disclaimer: The content provided on this website is for informational and educational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. The information presented does not constitute medical recommendations and should not be used to guide clinical decisions. Always seek the advice of a licensed healthcare provider regarding any medical condition or treatment. Do not disregard or delay professional medical care based on information found on this site. Some services may involve compounded medications that have not been reviewed by the FDA for safety or effectiveness; no therapeutic claims are made for these products. Visuals are for illustrative purposes only; individuals shown are not actual patients. Individual results may vary. See full safety information for more details.
Testosterone therapy is generally started to treat fatigue, low motivation, and other symptoms of low testosterone. But because testosterone also affects blood vessels, red blood cell production, and circulation, heart health is part of the conversation from the start.
That connection raises a natural question: is testosterone therapy safe for the heart long term? Current research offers a clearer answer than many men expect.
Why Heart Health Is Considered During Testosterone Therapy
Most people think of testosterone as a “male hormone” connected to sex drive or muscle. In reality, testosterone acts more like a messenger. It sends signals throughout the body, not just to one area.
Some of the systems that respond to testosterone include:
blood vessels
the bone marrow, where red blood cells are made
how the body handles cholesterol
how the immune system responds to inflammation
All of those systems also play a role in heart health. That overlap explains why a good provider doesn’t look at testosterone in isolation. They look at the whole picture.
Clinical guidelines recommend considering symptoms, lab findings, and heart risk factors together when deciding whether testosterone therapy is appropriate and how it should be monitored (Bhasin et al., 2018).
How Testosterone Relates to Blood Vessels
Inside every blood vessel is a thin inner lining. This lining helps blood move smoothly and signals when vessels should relax or tighten.
Healthy vessels expand easily. Under strain from aging, high blood pressure, insulin resistance, or chronic inflammation, they become less flexible.
Testosterone receptors are present in these vessel-lining cells. Research shows that men with low testosterone often have reduced vessel flexibility compared to men with normal levels (Empen et al., 2012). More recent studies link low testosterone with higher levels of inflammation inside blood vessels (Babcock et al., 2022).
This helps explain why hormone levels and circulation are connected. It does not mean testosterone therapy guarantees vascular improvement. It does mean the two systems influence each other.
Red Blood Cells, Blood Thickness, and Circulation
One consistent effect of testosterone therapy is increased production of red blood cells. Red blood cells carry oxygen, which supports energy use and tissue health.
This change is measured using a lab value called hematocrit, which reflects how much of the blood is made up of red blood cells.
Small increases in hematocrit are common
Larger increases can make blood thicker
When blood becomes thicker, it moves less easily through blood vessels. That can raise circulation-related risks for some individuals.
A hematocrit above about 54% is referred to as erythrocytosis and represents one of the most common side effects seen with testosterone therapy (Bachman et al., 2014; Basaria, 2014).
This is why hematocrit is checked:
before starting therapy
within the first few months
and at regular intervals afterward
Tracking this value allows providers to make adjustments early and maintain safety over time.
What Large Studies Have Found
One of the most important recent studies on this topic is the TRAVERSE trial. Researchers followed men with confirmed low testosterone who also had cardiovascular disease or significant risk factors.
Over several years, they tracked heart attacks, strokes, and cardiovascular deaths.
The rates of these major events were similar in men receiving testosterone and those receiving placebo (Lincoff et al., 2023).
The study did observe higher rates of pulmonary embolism and atrial fibrillation in the testosterone group. These findings support careful screening and follow-up, especially in men with clotting or rhythm history.
In 2024, the Androgen Society reviewed available data and concluded that testosterone therapy is not associated with increased risk of heart attack, stroke, or cardiovascular death when prescribed and monitored appropriately (Morgentaler et al., 2024).
A 2025 review in The New England Journal of Medicine reached similar conclusions while reinforcing the importance of ongoing monitoring (Bhasin & Snyder, 2025).
Taken together, current evidence shows cardiovascular stability for major events, with specific risks that providers actively watch for.
Why Ongoing Monitoring Is Part of Care
Testosterone therapy involves follow-up because the body changes over time.
Providers commonly monitor:
hematocrit and hemoglobin
blood pressure
cholesterol patterns
blood sugar markers
symptoms related to clotting or heart rhythm
Many of these values shift due to age, weight changes, sleep quality, stress, and lifestyle factors. Monitoring creates a clear picture of trends and supports informed adjustments throughout care.
Nitric Oxide and Blood Flow
Nitric oxide is a molecule produced by blood vessel cells. It helps blood vessels relax so blood can flow more easily.
Nitric oxide production depends on:
healthy blood vessel lining
balanced inflammation
availability of certain nutrients
Two nutrients involved in nitric oxide production are L-arginine and L-citrulline. Research shows these can lead to modest reductions in blood pressure, usually a few points. Broader cardiovascular outcomes have not been clearly established (Khalaf et al., 2019; Allerton et al., 2018).
Because of this role in circulation, these nutrients are sometimes included in general cardiovascular support formulations. For example, Superior Cardio contains L-arginine and L-citrulline as part of its ingredient profile. These ingredients are discussed in the context of supporting normal vascular physiology rather than as medical treatment.
What Responsible Testosterone Care Includes
Responsible testosterone care focuses on evaluation, follow-up, and communication.
Key elements include:
reviewing cardiovascular history and risk factors
confirming diagnosis using symptoms and lab data
monitoring blood work over time
adjusting care based on how the body responds
Clear information and regular follow-up help men engage in decisions grounded in evidence and clinical context.
Learn how cardiovascular health is evaluated as part of responsible testosterone care.
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Disclaimer
This content is provided for informational and educational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. The information presented does not constitute medical recommendations and should not be used to guide clinical decisions. Always seek the advice of a licensed healthcare provider regarding any medical condition or treatment. Do not disregard or delay professional medical care based on information found on this site. Some services may involve compounded medications that have not been reviewed by the FDA for safety or effectiveness. Visuals are for illustrative purposes only; individuals shown are not actual patients. Individual results may vary.
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit MedWatch or call 1-800-FDA-1088.
References
Basaria, S. (2014). Male hypogonadism. The Lancet, 383(9924), 1250–1263.
