It might be said that testosterone is what makes guys, guys. It gives them their characteristic deep voices, large muscles, and facial and body hair, distinguishing them from girls. It stimulates the development of the genitals at puberty, plays a role in sperm production, fuels libido, and contributes to regular erections. Additionally, it fosters the production of red blood cells, boosts mood, and assists cognition.
Over time, the testicular"machinery" which produces testosterone gradually becomes less powerful, and testosterone levels begin to fall, by approximately 1 percent a year, beginning in the 40s. As guys get into their 50s, 60s, and beyond, they may begin to have signs and symptoms of low testosterone such as reduced libido and sense of vitality, erectile dysfunction, diminished energy, decreased muscle mass and bone density, and anemia. Taken together, these symptoms and signs are often called hypogonadism ("hypo" meaning low working and"gonadism" referring to the testicles). Yet it is an underdiagnosed issue, with only about 5 percent of these affected receiving treatment.
Various studies have shown that testosterone-replacement therapy can offer a vast selection of benefits for men with hypogonadism, such as improved libido, mood, cognition, muscle mass, bone density, and red blood cell production. 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 difficulties. He's developed particular experience in treating low testosterone levels. In this interview, Dr. Morgentaler shares his perspectives on current controversies, the treatment strategies he utilizes his own patients, and he thinks specialists should rethink the possible connection between testosterone-replacement therapy and prostate cancer.Symptoms and diagnosis
What symptoms and signs of low testosterone prompt the typical man to see a physician?
As a urologist, I tend to observe guys because they have sexual complaints. The main hallmark of low testosterone is low sexual libido or desire, but another can be erectile dysfunction, and some other guy who complains of erectile dysfunction should possess his testosterone level checked. Men may experience other symptoms, like more difficulty achieving an orgasm, less-intense climaxes, a much smaller quantity of fluid out of ejaculation, and a feeling of numbness in the penis when they see or experience something which would normally be arousing.
The more of these symptoms you will find, the more probable it is that a man has low testosterone. Many physicians tend to discount those"soft symptoms" as a normal part of aging, however, they are often treatable and reversible by normalizing testosterone levels.
Are not those the very 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 reduce libido, including the BPH drugs finasteride (Proscar) and dutasteride (Avodart). Those drugs may also reduce the amount of the ejaculatory fluid, no question. But a decrease in orgasm intensity usually does not go along with therapy for BPH. Erectile dysfunction does not ordinarily go together with it either, though certainly if a person has less sex drive or less attention, it is more of a challenge to get a good erection.
How can you decide if or not a man is a candidate for testosterone-replacement therapy?
There are two ways we determine whether somebody has reduced 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. Generally men with the lowest testosterone have the most symptoms and men with highest testosterone possess the least. However, there are a number of guys who have reduced levels of testosterone in their blood and have no signs.
Looking at the biochemical numbers, The Endocrine Society* considers low testosterone for a entire testosterone level of less than 300 ng/dl, and I believe that is a sensible 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'll say,"Okay, you've got it." With testosterone, that break point is not quite as clear.
|*Note: The Endocrine Society publishes clinical practice guidelines with recommendations for who should and shouldn't receive testosterone therapy. visit homepage
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 discussion, 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 overall testosterone, or all of the testosterone in the human body. However, about half of the testosterone that's circulating in the bloodstream isn't readily available to cells. It's closely bound to a carrier molecule known as sex hormone--binding globulin, which we abbreviate as SHBG.
The available part of overall testosterone is known as free testosterone, and it is readily available to the cells. Even though it's just a little portion of the total, the free testosterone level is a pretty good indicator of reduced testosterone. It's not perfect, but the correlation is greater compared to testosterone.