More testosterone isn’t always better, and neither is less.
An analysis of previous research suggests that men whose testosterone strays too far in either direction face a higher risk of serious heart rhythm problems that can lead to stroke.
“These new findings assert that keeping testosterone level in mid-range of normal continues to be the right target,” Dr. Malek Cheikh, an endocrinologist at MedStar Union Memorial and MedStar Good Samaritan hospitals in Baltimore, who was not involved in the study, told The Epoch Times.
A U-Shaped Risk Curve
The review, published in September in the Journal of the Endocrine Society, looked at data from previous studies to understand how testosterone levels affect heart health. It found a “U-shaped” pattern, meaning that both low and high testosterone levels are linked to a higher risk of atrial fibrillation, a type of irregular heartbeat.
Testosterone influences the heart’s electrical system, and having either too little or too much can cause abnormal heart rhythms.
Studies suggest that high testosterone may shorten the time heart cells need to recover between heartbeats. This can allow abnormal electrical signals to circulate repeatedly, causing an abnormal heart rhythm. Low testosterone may disrupt calcium handling within heart cells, triggering extra electrical impulses that can initiate abnormal rhythms.
“Both too little and too much testosterone appear to raise the risk of atrial fibrillation, through separate biological mechanisms, which means the dose and the target level matter,” senior researcher Dr. Rajat Barua, a heart specialist at the Kansas City Veterans Affairs Medical Center in Missouri, said in a press statement.
Cheikh said the U-shaped model suggested by the new findings fits with existing research, but cautioned against treating the study’s suggested target—350 to 550 nanograms per deciliter (ng/dL)—as a strict rule for every patient.
“A more personalized targeting would serve our patients better,” he added.
Testosterone Can Increase Risks Through Many Pathways
When testosterone climbs too high, it can raise cardiovascular risk in several ways:
Testosterone stimulates the bone marrow to produce excess red blood cells. This can thicken the blood and directly increase the risk of developing blood clots.
Testosterone causes the body to retain sodium. The resulting fluid retention can increase blood pressure (hypertension), forcing the heart to work harder and increasing long-term cardiovascular strain.
High or unmonitored doses of testosterone can negatively affect cholesterol profiles. They can lower high-density lipoprotein (HDL, or “good” cholesterol) and elevate low-density lipoprotein (LDL, or “bad” cholesterol), accelerating plaque buildup in the arteries.
Personalized Treatment
The landmark TRAVERSE trial found that testosterone replacement therapy (TRT) was generally safe regarding major cardiac events in men with low testosterone and heart disease or elevated cardiovascular risk, though atrial fibrillation was more common with TRT.
Barua recommends that treatment should be personalized and carefully monitored, with testosterone levels kept within the normal range of 350 to 550 nanograms per deciliter, in line with current medical guidelines rather than increasing it to the high end.
Steady-release testosterone medications can help maintain stable levels. Doctors should also monitor patients’ heart rhythm, blood test results, blood pressure, and kidney and liver function during treatment.
Before starting testosterone therapy, doctors should consider factors such as obesity, sleep apnea, high blood pressure, and alcohol use, the researchers said.
What Screening Should Look Like Before Starting TRT
Men considering TRT should have a good understanding of their overall health status, Dr. Cory Rice, chief clinical advisor and a member of the medical advisory board at Biote, a hormone optimization company that trains and certifies healthcare providers in hormone therapy and TRT, who was not involved in the study, told The Epoch Times.
“Before starting TRT, the patient and doctor together need a solid read of their metabolic health,” said Rice, pointing to blood sugar or insulin levels, blood pressure, body composition, and an advanced lipid profile as starting points.
“Depending on the male patient’s risk factors such as age and family history,” Rice added, “that conversation should also include whether preventive screening for heart disease such as coronary calcium CT or stress testing makes sense.”
