A Harvard expert shares his thoughts on testosterone-replacement therapy
It could be stated that testosterone is what makes guys, men. It gives them their characteristic deep voices, big muscles, and facial and body hair, differentiating them from women. It stimulates the development of the genitals , plays a role in sperm production, fuels libido, and leads to normal erections. Additionally, it fosters the production of red blood cells, boosts mood, and assists cognition.
Over time, the "machinery" that produces testosterone gradually becomes less effective, and testosterone levels begin to fall, by about 1 percent a year, starting in the 40s. As guys get into their 50s, 60s, and beyond, they may begin to have signs and symptoms of low testosterone like reduced sex drive and sense of energy, erectile dysfunction, diminished energy, reduced muscle mass and bone density, and nausea. Taken together, these symptoms and signs are often called hypogonadism ("hypo" meaning low working and"gonadism" speaking to the testicles). Researchers estimate that the condition affects anywhere from two to six million men in the USA. Yet it's an underdiagnosed problem, with only about 5 percent of these affected receiving treatment.
But little consensus exists about what constitutes low testosterone, when testosterone supplementation makes sense, or what dangers patients face. Much of the current debate focuses on the long-held belief that testosterone may 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 reproductive and sexual problems. He has developed particular expertise in treating low testosterone levels. In this interview, Dr. Morgentaler shares his perspectives on current controversies, the treatment plans he utilizes his patients, and he thinks experts should reconsider the potential connection between testosterone-replacement treatment and prostate cancer.
Symptoms and diagnosisWhat symptoms and signs of low testosterone prompt that the average man to see a doctor?
As a urologist, I tend to see men because they have sexual complaints. The main hallmark of reduced testosterone is reduced sexual libido or desire, but another may be erectile dysfunction, and some other guy who complains of erectile dysfunction must possess his testosterone level checked. Men can experience different symptoms, like more trouble achieving an orgasm, less-intense climaxes, a much lesser quantity of fluid out of ejaculation, and a sense of numbness in the manhood when they see or experience something which would usually be arousing.
The more of the symptoms you will find, the more probable it is that a man has low testosterone. Many physicians often discount those"soft symptoms" as a normal part of aging, however, they're often treatable and reversible by decreasing testosterone levels.
Are not those the same symptoms that men have when they're treated for benign prostatic hyperplasia, or BPH?
Not exactly. There are a number of drugs that may lessen sex drive, including the BPH medication finasteride (Proscar) and dutasteride (Avodart). Those drugs may also reduce the quantity of the ejaculatory fluid, no question. But a reduction in orgasm intensity usually doesn't go together with therapy for BPH. Erectile dysfunction does not ordinarily go along with it either, though certainly if a person has less sex drive or less attention, it is more of a struggle to get a good erection.
How do you decide if or not a man is a candidate for testosterone-replacement therapy?
There are two ways we determine whether somebody has low testosterone. One is a blood test and the other one is by characteristic signs and symptoms, and the correlation between these two methods is far from perfect. Normally guys with the lowest testosterone have the most symptoms and guys with maximum testosterone possess the least. But there are some men who have reduced levels of testosterone in their blood and have no signs.
Looking purely at the biochemical numbers, The Endocrine Society* considers low testosterone for a entire testosterone level of less than 300 ng/dl, and I think that's a sensible guide. However, no one quite agrees on a few. It is not like diabetes, where if your fasting sugar is over a certain level, they'll say,"Okay, you've got it." With testosterone, that break point is not quite as apparent.
| *Note: The Endocrine Society publishes clinical practice guidelines with recommendations for who should and should not receive testosterone treatment. For a complete copy of the instructions, log on More about the author to www.endo-society.org. Is complete testosterone the right point to be measuring? Or if we are measuring something else? This is another area of confusion and great discussion, but I don't think that it's as confusing as it appears to be from the literature. When most physicians learned about testosterone in medical school, they learned about overall testosterone, or all of the testosterone in the body. However, about half of the testosterone that is circulating in the blood is not readily available to the cells. It's closely bound to a carrier molecule called sex hormone--binding globulin, which we abbreviate as SHBG. The available part of overall testosterone is called free testosterone, and it's readily available to cells. Though it's only a little fraction of the overall, the free testosterone level is a pretty good indicator of reduced testosterone. It's not ideal, but the correlation is greater compared to testosterone.
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