Testosterone Replacement: New Male Vigor? Or Health Hazard?

An expert panel of the Food and Drug Administration recently voted overwhelmingly to impose strict new limits on physician prescribing of the male sex hormone testosterone.

The FDA is not required to follow the recommendations of its expert panels, but the agency usually does, especially when the vote is as lopsided as this one—19 to one.

Advocates of hormone replacement call testosterone a fountain of youth that restores older men’s flagging sex drive and erections and returns them to lean, muscled, youthful vigor. Perhaps. But personally, I hope the FDA tightens up on testosterone big time. Here’s why:

• There’s good evidence that many men taking testosterone don’t need it and that serious safety issues remain unresolved.

• Since the millennium, the number of men taking the hormone has quadrupled to more than 2 million. But audits show that many received the hormone without sufficient blood testing to see if they really have what’s become known as Low T.

• Verifiable testosterone deficiency is rare in men under 65, but currently men 45 to 64 account for 60 percent of testosterone prescriptions.

• The debate over testosterone replacement feels eerily similar to the controversy decades ago surrounding hormone replacement therapy (HRT) in older women—also initially touted as youth restorer and later shown to increase risk of heart disease and breast cancer.


Testosterone is produced in the testicles. For decades, scientists have known that an unusually low blood level causes fatigue, depression, libido loss, erectile dysfunction, weight gain, and reduced muscle mass. All these problems can be cured with supplementation that returns blood levels to the normal range.

But supplemental testosterone also causes thickening of the blood, a risk factor for heart disease and stroke, and the hormone may spur the growth of prostate cancer, which is as common—and deadly—in men as breast cancer in women. Until recently, concerns about the hormone’s potentially serious downsides have prevented most doctors from prescribing it.

But at the end of the 20th century, a few researchers, notably Harvard’s Abraham Merganthaler, M.D., demonstrated that testosterone does not increase risk of prostate cancer, at least in short-term studies, and other researchers showed that supplementation may not be as closely associated with cardiovascular disease risk as was previously believed. As a result, increasing numbers of physicians have been prescribing it to an increasing number of men complaining of vague symptoms like fatigue.


The Endocrine Society, the medical organization that publishes authoritative guidelines for supplemental hormone therapy, recommends testosterone supplementation only for men who have unequivocally low levels, a finding that requires several blood tests. Multiple tests are necessary because testosterone levels fluctuate considerably during the day. Men who appear to have low levels in one test often show normal levels in others.

Meanwhile, a recent report by researchers at the University of Texas (UT) Medical Branch in Galveston shows that 25 percent of the men taking testosterone had just one blood test prior to receiving prescriptions, which suggests that doctors have prescribed it carelessly.

In addition, even if blood tests show a clear deficiency, the Endocrine Society guidelines insist that testosterone should not be prescribed unless men also report clear symptoms of deficiency, notably libido collapse. There is no evidence that the number of men reporting this has quadrupled since 2001, another suggestion that doctors are over-prescribing the hormone.

Finally, the UT study shows that the fastest growing group of men taking testosterone are in their 40s. But clear, symptomatic hormone deficiency is unusual before age 60, another indication that doctors are over-prescribing.

Rerun of the HRT Debacle in Women?

Furthermore, the testosterone story looks like a rerun of what happened with HRT for women thirty years ago. Doctors initially touted HRT as a sure way to preserve youthfulness, femininity, and sexual function while reducing risk of heart disease. Short-term studies showed that HRT reduced heart disease risk without increasing risk of breast cancer. But longer-term studies showed the opposite—a clear increase in heart disease and breast cancer risk. We have no long-term studies of testosterone supplementation, just short-term reports that all is well. But is it?

We may find out next year when researchers with the National Institutes of Health are scheduled to release the results of the T Trial, a years-long effort to determine the long-term effects—and side effects—of taking the hormone. Until then, we just don’t know.

Maybe testosterone is a godsend for older men. Maybe it doesn’t cause potentially life-threatening side effects. But the quadrupling of prescriptions over the past dozen years to many men who were inadequately tested suggests it’s being over-prescribed—which is why the FDA’s expert panel has exhorted to agency to limit prescriptions.

If you take testosterone, be aware that you’re a guinea pig in a vast uncontrolled experiment that may one day repay your current vitality boost with potentially serious consequences.

If you didn’t have multiple blood tests and clear deficiency symptoms before you received your prescription, you might want to rethink use of the hormone.

And if you’re considering supplementation because of breathless claims about stronger libido, firmer erections, and boosted vitality, I suggest you think twice. By a vote of 19 to one, the FDA expert panel shares my opinion.


Tavernise, S. “FDA Panel Backs Limits on Testosterone Drugs,” New York Times, 9-18-2014.

Rabin, R.C. “A High Price for Vigor,” New York Times, 2-4-2014.

LaPuma, J. “Don’t Ask Your Doctor About ‘Low T’,” New York Times, 2-4-2014.

O’Connor, A. “Study Adds Concerns About Cardiac Risks for Older Men Taking Testosterone,” New York Times, 1-30-2014.

Singer, N. “Selling That ‘New Man’ Feeling” New York Times, 11-24-2013.

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