Nearly a decade ago, researchers in Boston decided to see whether older men who were not in very good shape could benefit from daily doses of testosterone.
The scientists recruited several hundred volunteers and gave them the hormone or a placebo. Those taking testosterone got stronger, compared with those taking the placebo, and they could carry a load up stairs faster.
But they also had nearly five times the number of cardiovascular problems, including heart attacks and strokes, and safety monitors ended the trial early.
Since those findings were published in 2010, studies of testosterone treatment have produced mixed results. A 2012 study of veterans aged 40 and over with low testosterone found that those treated with the hormone were less likely to die, but more recent reports, including one published last week, have documented an increase in cardiovascular risk in men over age 65 taking testosterone, as well as in younger men with a history of heart disease.
Officials at the Food and Drug Administration said on Friday that they were reassessing the safety of testosterone products in light of the recent studies, and will investigate rates of stroke, heart attack and death in men using the drugs.
In recent years, testosterone has been heavily promoted as a cure-all for low energy, low libido, depression and other ills among middle-aged men. “Low T” is a ubiquitous diagnosis, heard in television commercials and locker rooms.
Between 2001 and 2011, hormone use by men 40 and over nearly quadrupled. By the end of that period, nearly one in 25 men in their 60s was taking testosterone.
Though the drug is indicated for men with abnormally low testosterone levels, a condition called hypogonadism, doctors have been prescribing it to many men with normal levels.
“For people with truly low testosterone levels, the benefits outweigh the risks,” said Dr. Brad Anawalt of the University of Washington in Seattle and an author of the study that found testosterone could help certain veterans. “But for millions of others, it’s in the same category as snake oil.”
Many physicians have become more willing to prescribe testosterone to people who don’t fit the classical diagnosis of hypogonadism and have only borderline low levels that may be related to normal age-related hormonal declines, he said. Testosterone levels begin to decline by about 1 percent a year in men at age 30.
“There are what I would label testosterone factories out there, and it’s terrifying because we don’t know what the long-term safety profile is,” Dr. Anawalt said.
Some critics say the trend is reminiscent of another hormonal regimen with a sexy allure — estrogen, or as it was commonly called, hormone replacement therapy — which was widely promoted to menopausal women for decades based on scanty evidence of benefit and inadequate scrutiny of the potential harm.
“We’re giving people hormones that we don’t know they need for a disease that we don’t know they have, and we don’t know if it’ll help them or harm them,” said Dr. Lisa Schwartz, a professor at the Dartmouth Institute for Health Policy and Clinical Practice, who wrote a 2013 paper about the marketing of low testosterone as a disease in need of a treatment.
Hormone treatment for women — typically a combination of estrogen and synthetic progesterone, unless the woman has undergone hysterectomy — is used to treat menopausal symptoms such as hot flashes, mood swings and low sexual desire. But for years physicians were convinced that estrogen protected women from heart disease, and promoted it as a long-term preventive regimen.
Some 20 percent of menopausal women were taking hormones by the time the Women’s Health Initiative finally put the hypothesis to the test in a large government-sponsored clinical trial.
The results stunned experts: Rather than protecting women from heart disease, the popular estrogen and progestin combination increased the risk of blood clots, strokes and breast cancer when compared with a placebo, and did not protect from heart disease.
Now there are calls for a similar, government-funded clinical trial to establish the benefits and risks of testosterone hormone treatment for men. The National Institutes of Health is sponsoring a large randomized controlled trial, called the T trial, designed to see whether older men who take testosterone actually experience better physical, sexual and cognitive function, and whether the hormone reduces risk factors for heart disease and diabetes.
The trial is not designed to determine the long-term risks of treatment, but rather to determine whether the treatment has health benefits. Though low testosterone is associated with health problems in older men, such as bone loss, decreased strength and decreased sex drive, it is not clear that low testosterone is the cause of these problems or that boosting testosterone reverses them, said Dr. Ronald Swerdloff of the David Geffen School of Medicine at U.C.L.A.
Testosterone also declines in men who are obese and don’t exercise, Dr. Anawalt pointed out.
Mary Schooling, a Hunter College professor of public health, is convinced testosterone is harmful for older men, and a trial like the Women’s Health Initiative would be a mistake. “It’s in the pharmaceutical companies’ interest to have a trial going on for 10 years,” she said. “In that time, they can continue to sell testosterone.
Dr. Anawalt has been taking a firm approach with his patients, often telling them that he’s not convinced that they really suffer from low testosterone. “There are so many men out there looking for the elixir of youth,” he said.
“I say, ‘I’m not going to prescribe a therapy for you for the rest of your life if I’m not sure it’s safe for you. And by the way, if you could exercise a little more, lose a couple pounds and eat more healthfully — there’s evidence you can raise your testosterone that way.’ ”
By RONI CARYN RABIN