• Posted September 1, 2026

High Testosterone Increases Risk Of Heart Rhythm Disorder, Review Finds

“Low T” is a trendy health topic, with aging men sold testosterone as a veritable Fountain of Youth.

But too much testosterone can also pose a risk to heart health, a new evidence review says.

Men with low testosterone or high testosterone levels both have a higher risk of atrial fibrillation, a heart health disorder that increases risk of stroke, researchers report in the Journal of the Endocrine Society.

“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,” said senior researcher Dr. Rajat Barua in a news release. He is a cardiologist at the Kansas City Veterans Affairs Medical Center in Kansas City, Missouri.

For the review, researchers analyzed data from previous studies to look into the heart risks associated with low and high levels of testosterone.

“Testosterone replacement therapy is widely prescribed for middle-aged and older men, and atrial fibrillation is a heart rhythm disorder that increases stroke risk and often requires lifelong blood-thinning medication,” Barua said.

Results indicated a U-shaped curve, in which both low and high testosterone levels increased risk of atrial fibrillation.

Testosterone impacts the heart’s electrical system, with either low or high levels potentially causing abnormal heart rhythms, researchers wrote in their study.

“What the review argues is that treatment should be individualized and monitored,” Barua said.

Specifically, doctors should aim to restore testosterone to regular levels, close to the middle of the normal range of 350-550 dg/dL total testosterone, rather than pushing it to the high end, researchers said.

Steady-release testosterone drugs can help stabilize levels, and doctors should keep a close eye on heart rhythm, blood tests, blood pressure, and kidney and liver function, researchers said.

Doctors also should account for obesity, sleep apnea, high blood pressure and alcohol use before starting testosterone therapy, researchers added.

More information

The Mayo Clinic has more on testosterone therapy.

SOURCE: The Endocrine Society, news release, Sept. 1, 2026