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 boosts the production of red blood cells, boosts mood, and aids cognition.
As time passes, the "machinery" which makes testosterone slowly becomes less powerful, and testosterone levels start to fall, by approximately 1% a year, starting in the 40s. As men get in their 50s, 60s, and beyond, they might start to have signs and symptoms of low testosterone like lower libido and sense of energy, erectile dysfunction, decreased energy, decreased muscle mass and bone density, and nausea. 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 illness affects anywhere from two to six million men in the United States. Yet it's an underdiagnosed problem, with just about 5% of these affected undergoing therapy.
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 he thinks experts should reconsider the potential 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 may be erectile dysfunction, and any guy who complains of erectile dysfunction must get his testosterone level checked. Men can experience other 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 manhood when they see or experience something that would usually be arousing.
The more of the symptoms there are, 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 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 normally does not go along with treatment 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's more of a challenge to have a fantastic erection.
How can you determine whether a person is a candidate for testosterone-replacement treatment?
There are two ways that 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 perfect. Generally men with the lowest testosterone have the most symptoms and men with maximum testosterone possess the least. However, 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 for 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'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 home guidelines with recommendations for who should and should not receive testosterone treatment. Go Here
Is total testosterone the right thing to be measuring? Or should we be measuring something else?
Well, this is another area of confusion and great debate, but I don't think that it's as confusing as it is apparently from the literature. When most physicians learned about testosterone in medical school, they heard about overall testosterone, or all the testosterone in the body. But about half of the testosterone that's circulating in the blood isn't readily available to cells. It is closely bound to a carrier molecule known as sex hormone--binding globulin, which we abbreviate as SHBG.
The available portion of overall testosterone is called free testosterone, and it's readily available to the cells. Though it's only a small portion of this total, the free testosterone level is a pretty good indicator of low testosterone. It is not ideal, but the correlation is greater than with testosterone.
Do time of day, diet, or other elements affect testosterone levels?
For years, the recommendation was to get a testosterone value early in the morning because levels begin to fall after 10 or 11 a.m.. However, the data behind this recommendation were attracted to healthy young men. Two recent studies showed little change in blood testosterone levels in men 40 and mature over the course of this day. One reported no change in average testosterone until after 2 Between 6 and 2 p.m., it went down by 13%, a modest sum, and probably not enough to affect diagnosis. Most guidelines nevertheless say it is important to do the evaluation in the morning, but for men 40 and over, it probably doesn't matter much, provided that they get their blood drawn before 5 or 6 p.m.
There are a number of very interesting findings about dietary supplements. For instance, it appears that individuals that have a diet low in protein have lower testosterone levels than men who eat more protein. But diet hasn't been researched thoroughly enough to make any clear recommendations.
What kinds of testosterone-replacement treatment are available? *
The earliest form is the injection, which we still use because it is cheap and because we reliably become fantastic testosterone levels in nearly everybody. The disadvantage is that a man should come in every couple of weeks to find a shot. A roller-coaster effect can also occur as blood testosterone levels peak and return to baseline. [Watch"Exogenous vs. endogenous testosterone," above.]
Topical treatments help maintain a more uniform amount of blood glucose. The first kind of topical treatment was a patch, but it has a very high rate of skin irritation. In one study, as many as 40% of men who used the patch developed a reddish area in their skin. That restricts its usage.
The most widely used testosterone preparation in the United States -- and the one I start almost everyone off with -- is a topical gel. The gel comes from tiny tubes or within a unique dispenser, and you rub it on your shoulders or upper arms once a day. According to my experience, it has a tendency to be consumed to great degrees in about 80% to 85 percent of men, but leaves a significant number who do not consume sufficient for this to have a favorable impact. [For details on several different formulations, see table ]
Are there any downsides to using dyes? How much time does it require them to get the job done?
Men who begin using the implants need to return in to have their own testosterone levels measured again to be certain they're absorbing the right amount. Our target is the mid to upper range of normal, which usually means around 500 to 600 ng/dl. The concentration of testosterone in blood actually goes up quite quickly, within a few doses. I usually measure it after 2 weeks, even although symptoms may not alter for a month or two.