It’s no secret that testosterone therapy, touted as a modern way to deal with muscle weakness, low energy and decreased sex drive, is booming. Thousands of men take testosterone pills, rub on testosterone creams and receive regular testosterone injections. But testosterone therapy risks are severe—and life-threatening.

A decades-old study examined how testosterone hormones impacted aging men. Researchers linked various health risks, most prominently cardiovascular complications, to the low-T craze.

Testosterone Therapy Risks

In the Data 

The 2010 study published in the New England Journal of Medicine, titled “Adverse Events Associated with Testosterone Administration,” measured the risk-benefit profile of testosterone therapy.

During the study, researchers provided one group of men with hormones and another with placebos. The men who took testosterone hormones were four times as likely to have a heart attack or stroke. The safety concerns were so serious that researchers halted the trial.

Another study, published in Pub Med, found an increased cardiac risk for men over the age of 65. The study also showed a higher complication risk for younger men with a history of heart disease.

A Rising Number of Prescriptions 

From 2001 to 2011, the number of men aged 40 years and older using testosterone hormones quadrupled. Now, nearly one in 25 men in their 60s were taking testosterone, according to the JAMA Network.

Testosterone levels naturally decline by an estimated 1 percent each year when men hit age 30, and at a higher rate when men are obese and inactive. But many men with naturally decreasing testosterone levels are now requesting testosterone drugs.

Testosterone therapy is meant to treat a condition called hypogonadism, an abnormally low level of testosterone. The rise in prescription requests is due, in part, to pharmaceutical manufacturers, who continue to play on anti-aging trends and advertise to older men.

FDA Safety Communication 

In March 2015, the Food and Drug Administration issued a safety communication and updated testosterone labels to reflect the associated cardiac risk. The agency asserts that testosterone drugs are “approved only for men who have low testosterone levels caused by certain medical conditions.”

Many men taking testosterone medications experience feelings of revived youth. But those feeling are temporary and don’t come without a cost.

Have you taken testosterone drugs? Learn more about the cardiovascular risks linked to low testosterone therapy now.