A Harvard expert shares his thoughts on testosterone-replacement therapy
A meeting with Abraham Morgentaler, M.D.
It could be said that testosterone is the thing that makes guys, guys. It gives them their characteristic deep voices, large muscles, and facial and body hair, differentiating them from girls. It stimulates the growth of the genitals at puberty, plays a role in sperm production, fuels libido, and leads to regular erections. It also fosters the creation of red blood cells, boosts mood, and aids cognition.
Over time, the "machinery" which produces testosterone gradually becomes less effective, and testosterone levels begin to fall, by about 1 percent a year, beginning in the 40s. As guys get into their 50s, 60s, and beyond, they may begin to have symptoms and signs of low testosterone such as lower libido and sense of vitality, erectile dysfunction, diminished energy, decreased muscle mass and bone density, and anemia. Taken together, these signs and symptoms are often referred to as hypogonadism ("hypo" meaning low functioning and"gonadism" speaking to the testicles). Researchers estimate that the condition affects anywhere from two to six million men in the United States. Yet it's an underdiagnosed problem, with just about 5 percent of those affected undergoing therapy.
Much of the current debate focuses on the long-held belief that testosterone can stimulate prostate cancer.
Dr. Abraham Morgentaler, an associate professor of surgery at Harvard Medical School and the director of Men's Health Boston, specializes in treating prostate diseases and male sexual and reproductive problems. He has developed particular experience in treating low testosterone levels. In this interview, Dr. Morgentaler shares his views on current controversies, the treatment plans he uses with his own patients, and he believes experts should reconsider the potential link between testosterone-replacement treatment and prostate cancer.
Symptoms and diagnosisWhat signs and symptoms of low testosterone prompt the typical man to find a doctor?
As a urologist, I have a tendency to see guys since they have sexual complaints. The main hallmark of low testosterone is reduced sexual desire or libido, but another may be erectile dysfunction, and some other man who complains of erectile dysfunction must get his testosterone level checked. Men can experience other symptoms, like more difficulty achieving an orgasm, less-intense climaxes, a lesser amount of fluid from ejaculation, and a sense of numbness in the penis when they see or experience something which would usually be arousing.
The more of these symptoms you will find, the more likely it is that a man has low testosterone. Many physicians often dismiss these"soft symptoms" as a normal part of aging, however, they are often treatable and reversible by normalizing testosterone levels.
Are not those the same symptoms that men have when they are treated for benign prostatic hyperplasia, or BPH?
Not precisely. There are a number of drugs which may lessen sex drive, including the BPH medication finasteride (Proscar) and dutasteride (Avodart). Those drugs can also decrease the quantity of the ejaculatory fluid, no wonder. But a decrease in orgasm intensity normally does not go along with therapy for BPH. Erectile dysfunction does not usually go along with it either, though surely if a person has less sex drive or less interest, it is more of a struggle to get a fantastic erection.
How can you decide whether or not a person is a candidate for testosterone-replacement treatment?
There are just two ways that we determine whether someone has reduced testosterone. One is a blood test and the other one is by characteristic symptoms and signs, and the correlation between those two approaches is far from ideal. Normally guys with the lowest testosterone have the most symptoms and guys with maximum testosterone have the least. But there are some men who have low levels of testosterone in their blood and have no signs.
Looking at the biochemical numbers, The Endocrine Society* considers low testosterone to be a total testosterone level of less than 300 ng/dl, and I think that's a reasonable guide. But no one quite agrees on a number. It's not like diabetes, where if your fasting glucose is above a certain level, they will say,"Okay, you've got it." With testosterone, that break point isn't quite as apparent.
| *Notice: The Endocrine Society recommends clinical practice guidelines next with recommendations for who should and should not receive testosterone investigate this site treatment. Is complete testosterone the ideal point to be measuring? Or if we are measuring something different? This is just another area of confusion and good debate, but I don't think it's as confusing as it appears to be in the literature. When most doctors learned about testosterone in medical school, they learned about total testosterone, or all the testosterone in the human body. However, about half of their testosterone that is circulating in the blood isn't readily available to the cells. It's tightly bound to a copyright molecule called sex hormone--binding globulin, which we abbreviate as SHBG. The biologically available portion of overall testosterone is known as free testosterone, and it is readily available to cells. Though it's only a small fraction of the total, the free testosterone level is a pretty good indicator of reduced testosterone. It is not ideal, but the correlation is greater than with testosterone.
Do time daily, diet, or other elements influence testosterone levels? For years, the recommendation has been to receive a testosterone value early in the morning because levels start to fall after 10 or even 11 a.m.. However, the data behind that recommendation were attracted to healthy young men. Two recent studies demonstrated little change in blood glucose levels in men 40 and older over the course of this day. One reported no change in average testosterone until after 2 p.m. Between 6 and 2 p.m., it went down by 13 percent, a modest sum, and probably not enough to influence identification. Most guidelines nevertheless say it's important to perform the test in the morning, but for men 40 and over, it likely doesn't matter much, as long as they obtain their blood drawn before 5 or 6 p.m. There are some rather interesting findings about diet. By way of example, it appears that those who have a diet low in protein have lower testosterone levels than males who eat more protein. But diet hasn't been researched thoroughly enough to make any clear recommendations.
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