Testosterone is a naturally produced hormone that plays many roles in men’s health, regulating sex drive, muscular definition, bone strength, and more. As men age, their levels of testosterone naturally decline, and there has been hot debate over whether testosterone supplementation for men with low levels of testosterone — dubbed “low T” — is beneficial or risky for health.
In February, a large, randomized controlled trial — the gold standard for judging the effectiveness of a medical treatment — found that testosterone supplementation for men over 65 with significant testosterone deficiency modestly improved sexual function and mood. The government-funded study, which followed 790 men, ages 65 and older, over a year, was a landmark investigation in this controversial area of medicine.
But it did not end the controversy. Now, a new systematic review of the testosterone literature, in which Georgetown University Medical Center researchers collected and analyzed 156 randomized controlled trials, has concluded that there are no health benefits to testosterone supplementation for low T — not even for erectile dysfunction.
“There were so many claims being made for what testosterone could do for men that we wanted to investigate what the actual evidence was,” says lead author Adriane Fugh-Berman, a pharmaceutical marketing expert at Georgetown and paid expert witness in litigation regarding pharmaceutical marketing practices. To her, the conclusions were clear: “There are known harms and minimal to no benefits,” she says.
Clinicians in the field disagree. The review is “a triumph of anti-pharmaceutical zealotry over science” that “contradicts numerous professional groups and meta-analysis, and is not supported by anybody in the field,” says Abraham Morgentaler, a urologist at Harvard Medical School, author of “Testosterone for Life: Recharge Your Vitality, Sex Drive, Muscle Mass, and Overall Health,” and a paid consultant for pharmaceutical companies.
“All they’ve done is list a large number of testosterone studies, without understanding important issues in the field, and then drawn their own conclusions without any scientific basis,” says Morgentaler.
For years, testosterone was marketed as a solution to many of the ills of male aging, from low energy to moodiness. Then, studies linked testosterone supplementation to increased risk of prostate cancer and heart attacks. In 2014, the Food and Drug Administration changed testosterone labeling to limit its use to men who lack testosterone because of a medical condition.
The current review is Fugh-Berman’s first published scientific study of testosterone supplementation, and it conflicts with several previous papers. In July, an international group of 18 experts, chaired by Morgentaler, published a consensus resolution declaring that testosterone deficiency is a “well-established, clinically significant medical condition” and testosterone supplementation for men with this deficiency is “effective, rational, and evidence-based.” Notably, however, 11 of the consensus participants cited receiving consulting or speaking fees from the pharmaceutical industry.
In 2014, a team of endocrinologists — who cited no conflicts of interest with the pharmaceutical industry — re-analyzed data from 41 RCTs concerning testosterone supplementation for the treatment of sexual dysfunction. They concluded the hormone does improve sexual function for men who don’t produce enough testosterone, but not necessarily for men who do.
“No reputable physician is suggesting that men without low testosterone get treated,” notes Morgentaler. “The data are clear that for men who have low levels of documented testosterone, there are clear-cut benefits in erectile function and libido.”