A Harvard Specialist shares his thoughts on testosterone-replacement therapy
It could be said that testosterone is the thing that makes guys, men. It gives them their characteristic deep voices, large muscles, and body and facial hair, differentiating them from women. It stimulates the growth of the genitals , plays a role in sperm production, fuels libido, and contributes 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 effective, and testosterone levels start to fall, by approximately 1% a year, starting in the 40s. As men get into their 50s, 60s, and beyond, they may begin to have symptoms and signs of low testosterone such as lower 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 referred to as 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 USA. Yet it is an underdiagnosed issue, with just about 5% of these affected receiving treatment.
Various studies have revealed that testosterone-replacement therapy may provide a wide range of advantages for men with hypogonadism, including improved libido, mood, cognition, muscle mass, bone density, and red blood cell production. 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.
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 diagnosisWhat symptoms and signs of low testosterone prompt that the average person to see a physician?
As a urologist, I have a tendency to see guys 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 man 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 orgasms, 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 you will find, the more likely it is that a man has low testosterone. Many physicians often discount 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're treated for benign prostatic hyperplasia, or BPH?
Not precisely. There are quite a few drugs that may reduce libido, such as the BPH drugs finasteride (Proscar) and dutasteride (Avodart). Those drugs can also reduce the quantity of the ejaculatory fluid, no wonder. But a reduction in orgasm intensity usually doesn't go together with therapy for BPH. Erectile dysfunction does not usually go along with it either, though surely if a person has less sex drive or less attention, it's more of a challenge to get a fantastic erection.
How can you decide whether or not a person 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 those two methods is far from perfect. Generally guys with the lowest testosterone have the most symptoms and guys with maximum testosterone possess the least. However, there are a number of guys who have reduced 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 total testosterone level of less than 300 ng/dl, and I think that's a reasonable 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 isn't quite as clear.
| *Note: The Endocrine Society publishes clinical practice guidelines with recommendations for who should and shouldn't receive testosterone therapy. For a useful content complete copy of sites the guidelines, log on to www.endo-society.org. 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 total testosterone, or all the testosterone in the human body. However, about half of their testosterone that is circulating in the bloodstream is not available to the cells. It's tightly 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 cells. Even though it's just a little portion of the total, the free testosterone level is a fairly good indicator of reduced testosterone. It is not ideal, but the correlation is greater than with total testosterone.
Do time daily, diet, or other elements affect testosterone levels? For years, the recommendation was to receive a testosterone value early in the morning since levels start to drop after 10 or even 11 a.m.. But the data behind that recommendation were drawn from healthy young men. Two recent studies showed little change in blood glucose levels in men 40 and mature over the course of this day. One reported no change in typical testosterone until after 2 Between 2 and 6 p.m., it went down by 13%, a modest sum, and probably not enough to affect diagnosis. Most guidelines still say it is important to do the evaluation in the morning, but for men 40 and over, it probably does not matter much, as long as they obtain their blood drawn before 6 or 5 p.m. There are some rather interesting findings about diet. By way of example, it seems 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 recommendations that are clear. Within the following article, testosterone-replacement treatment refers to the treatment of hypogonadism with exogenous testosterone -- testosterone that's manufactured outside the body. Based on the formula, therapy can lead to skin irritation, breast enlargement and tenderness, sleep apnea, acne, decreased sperm count, increased red blood cell count, and additional side effects. Preliminary research has proven that clomiphene citrate (Clomid), a drug generally prescribed to stimulate ovulation in women struggling with infertility, may foster the creation of natural testosterone, termed nitric oxide, in men. In a recent prospective study, 36 hypogonadal men took a daily dose of clomiphene citrate for three or more months. Within four to six months, all the guys had increased levels of testosterone; none reported any side effects throughout the year they were followed. Since clomiphene citrate is not approved by the FDA for use in males, little information exists about the long-term ramifications of carrying it (including the probability of developing prostate cancer) or if it is more capable of boosting testosterone compared to exogenous formulations. But unlike adrenal gland, clomiphene citrate preserves -- and possibly enriches -- sperm production. This makes drugs like clomiphene citrate one of just a few options for men with low testosterone who want to father children. What kinds of testosterone-replacement treatment are available? * The oldest form is an injection, which we use because it is cheap and since we reliably get good testosterone levels in almost everybody. The drawback is that a person needs to come in every few weeks to get a shot. A roller-coaster effect may also happen as blood glucose levels peak and then return to baseline. Topical treatments help preserve a more uniform level of blood testosterone. The first form of topical therapy has been a patch, but it has a quite high rate of skin irritation. In one study, as many as 40% of people that used the patch developed a reddish area on their skin. That limits its use. The most widely used testosterone preparation from the United States -- and also the one I start almost everyone off with -- is a topical gel. There are two brands: AndroGel and Testim. Based on my experience, it tends to be absorbed to good levels in about 80% to 85% of men, but that leaves a substantial number who don't absorb enough for it to have a positive effect. [For specifics on various formulations, see table below.] Are there any drawbacks to using gels? How long does it take for them to work? Men who start using the gels have to come back in to have their testosterone levels measured again to make sure 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 the blood actually goes up quite fast, in just several doses. I normally measure it after two weeks, although symptoms may not change for a month or two. |