The percentage of middle-aged men in the United States taking testosterone to treat symptoms of low testosterone, or "low T," has increased substantially in recent years, according to a study.
According to the study, over the last decade, prescriptions for testosterone therapy among men ages 40 and older increased more than threefold, from 0.81 percent in 2001, to nearly 3 percent in 2011, the Huffington Post reported.
"This trend has been driven, in large part, by direct-to-consumer marketing campaigns that have targeted middle-aged men, and the expansion of clinics specializing in the treatment of low testosterone - or 'low-T centers'," study researcher Dr. Jacques Baillargeon, an associate professor in preventive medicine at the University of Texas Medical Branch, said in a statement.
Despite the rise, study results have been conflicting about whether men benefit from the treatment, and to what extent they might be harmed by it.
Testosterone treatments have been shown to increase muscle strength and sex drive, but they can also temporarily decrease sperm count and impair fertility.
Some studies have suggested a link between testosterone therapy and prostate cancer.
And while testosterone levels naturally decrease with age, exactly what level constitutes low T, also known as hypogonadism, is controversial.
Doctors typically treat men for hypogonadism if they have symptoms of low testosterone and their testosterone levels are below 300 nanograms per deciliter.
The research is published in the journal JAMA Internal Medicine.