It could 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 leads to regular erections. It also fosters the creation of red blood cells, boosts mood, and assists cognition.
Over time, the testicular"machinery" which makes testosterone gradually becomes less powerful, and testosterone levels begin to fall, by approximately 1 percent a year, starting 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 reduced 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 called hypogonadism ("hypo" significance low working and"gonadism" referring to the testicles). Researchers estimate that the condition affects anywhere from two to six million men in the USA. Yet it is an underdiagnosed issue, with only about 5% of these affected receiving treatment.
But little consensus exists on 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 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 ailments 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 why he believes specialists should rethink the possible connection between testosterone-replacement therapy and prostate cancer.Symptoms and diagnosis
What signs and symptoms of low testosterone prompt the average man to see a physician?
As a urologist, I tend to see men since they have sexual complaints. The main hallmark of reduced testosterone is reduced sexual libido or desire, but another can be erectile dysfunction, and any man who complains of erectile dysfunction should possess his testosterone level checked. Men may experience different symptoms, such as more trouble achieving an orgasm, less-intense climaxes, a lesser quantity 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 probable it is that a man has low testosterone. Many physicians tend to discount these"soft symptoms" as a normal part of aging, but they're often treatable and reversible by decreasing testosterone levels.
Aren't those the same symptoms that guys have when they are treated for benign prostatic hyperplasia, or BPH?
Not exactly. There are a number of medications which may lessen sex drive, including the BPH medication finasteride (Proscar) and dutasteride (Avodart). Those drugs may also reduce the amount of the ejaculatory fluid, no question. However a decrease in orgasm intensity normally does not go along with treatment for BPH. Erectile dysfunction does not ordinarily go together with it , 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 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 is by characteristic signs and symptoms, and the correlation between these 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 symptoms.
Looking purely at the biochemical numbers, The Endocrine Society* considers low testosterone to be a entire testosterone level of less than 300 ng/dl, and I believe that is a sensible guide. However, no one really agrees on a few. It is similar to diabetes, in which if your fasting sugar is over a certain level, they will say,"Okay, you've got it." With testosterone, that break point isn't quite as apparent.
|*Note: The Endocrine Society publishes clinical practice guidelines with recommendations for who should and should not receive testosterone treatment.
Is total testosterone the right thing to be measuring? Or if we are measuring something different?
This is just another area of confusion and good discussion, but I do not 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. But about half of the testosterone that's circulating in the bloodstream isn't readily available to cells. It's tightly bound to a carrier molecule called sex hormone--binding globulin, which we abbreviate as SHBG.
The biologically available portion of overall testosterone is called free testosterone, and it's readily available to the cells. Though it's only a little fraction of the overall, the free testosterone level is a fairly good indicator of low testosterone. It's not ideal, but the correlation is greater compared to total testosterone.