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, differentiating them from girls. It stimulates the growth of the genitals , 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 start to fall, by approximately 1% a year, starting in the 40s. As guys get in their 50s, 60s, and beyond, they might start to have symptoms and signs of low testosterone like reduced libido and sense of vitality, erectile dysfunction, decreased energy, decreased muscle mass and bone density, and anemia. Taken together, these signs and symptoms are often called hypogonadism ("hypo" meaning low working and"gonadism" referring to the testicles). Researchers estimate that the condition affects anywhere from two to six million men in the United States. Yet it is an underdiagnosed problem, with only about 5 percent of those affected receiving treatment.
Various studies have shown that testosterone-replacement therapy may provide a wide 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 can stimulate prostate cancer.
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 uses with his patients, and he thinks specialists should rethink the potential connection between testosterone-replacement treatment and prostate cancer.Symptoms and diagnosis
What signs and symptoms of low testosterone prompt the typical man to find a physician?
As a urologist, I tend to observe men because they have sexual complaints. The main hallmark of low testosterone is reduced 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 orgasms, a much smaller amount of fluid out of ejaculation, and a feeling 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 tend to discount these"soft symptoms" as a normal part of aging, however, they're often treatable and reversible by decreasing testosterone levels.
Are not those the very same symptoms that guys have when they're treated for benign prostatic hyperplasia, or BPH?
Not precisely. There are a number of medications that may reduce libido, such as the BPH drugs finasteride (Proscar) and dutasteride (Avodart). Those drugs may also reduce the quantity of the ejaculatory fluid, no question. However a reduction in orgasm intensity normally does not go together with treatment for BPH. Erectile dysfunction does not ordinarily go along with it either, though surely if somebody has less sex drive or less attention, it is more of a struggle to have a fantastic erection.
How do you determine whether a man is a candidate for testosterone-replacement therapy?
There are just two ways we determine whether someone has reduced testosterone. One is a blood test and the other is by characteristic symptoms and signs, and the correlation between these two methods is far from ideal. Generally men with the lowest testosterone have the most symptoms and men with maximum testosterone have the least. However, there are some men who have reduced levels of testosterone in their blood and have no signs.
Looking purely at the biochemical amounts, The Endocrine Society* considers low testosterone for a total testosterone level of less than 300 ng/dl, and I think that's a sensible guide. However, no one really agrees on a few. It's not like diabetes, in which if your fasting sugar is above a certain level, they will say,"Okay, you've got it." With testosterone, that break point is not quite as clear.
|*Note: The Endocrine Society recommends clinical practice guidelines with recommendations for who should and shouldn't receive testosterone therapy. For a complete check this site out copy of these instructions, log on wikipedia reference to www.endo-society.org.
Is total testosterone the right thing to be measuring? Or if we are measuring something different?
This is another area of confusion and great discussion, but I don't think it's as confusing as it appears to be in the literature. When most physicians learned about testosterone in medical school, they learned about total testosterone, or all the testosterone in the body. But about half of their testosterone that's circulating in the blood is not available to the cells.
The biologically available portion of overall testosterone is called free testosterone, and it is readily available to cells. Nearly every laboratory has a blood test to measure free testosterone. Though it's only a small fraction of the total, the free testosterone level is a fairly good indicator of reduced testosterone. It's not ideal, but the significance is greater compared to testosterone.