It could be stated that testosterone is what makes guys, guys. It gives them their characteristic deep voices, large muscles, and body and facial hair, distinguishing them from girls. It stimulates the growth of the genitals , plays a role in sperm production, fuels libido, and contributes to regular erections. It also boosts the creation of red blood cells, boosts mood, and aids cognition.
As time passes, the testicular"machinery" that produces testosterone gradually becomes less effective, and testosterone levels begin to fall, by about 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 sex drive and sense of vitality, erectile dysfunction, diminished energy, decreased muscle mass and bone density, and anemia. 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 condition affects anywhere from two to six million men in the United States. Yet it's an underdiagnosed issue, with just about 5% of those affected undergoing therapy.
But little consensus exists about what constitutes low testosterone, when testosterone supplementation makes sense, or what risks 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 sexual and reproductive difficulties. He has developed specific experience in treating lower testosterone levels. In this interview, Dr. Morgentaler shares his views on current controversies, the treatment strategies he uses with his own patients, and why he believes specialists should rethink the potential link between testosterone-replacement therapy and prostate cancer.
Symptoms and browse around here diagnosisWhat signs and symptoms of low testosterone prompt the average man to see a physician?
As a urologist, I have a tendency to observe guys since they have sexual complaints. The main hallmark of reduced testosterone is reduced sexual libido or desire, but another may be erectile dysfunction, and any man who complains of erectile dysfunction should get his testosterone level checked. Men may experience other symptoms, such as more difficulty achieving an orgasm, less-intense orgasms, a smaller amount of fluid from ejaculation, and a feeling of numbness in the penis when they see or experience something that would normally be arousing.
The more of these symptoms there are, the more likely it is that a man has low testosterone. Many physicians tend to dismiss these"soft symptoms" as a normal part of aging, but they are often treatable and reversible by normalizing testosterone levels.
Are not those the very same symptoms that guys have when they are treated for benign prostatic hyperplasia, or BPH?
Not precisely. There are quite a few medications which may reduce libido, such as the BPH medication finasteride (Proscar) and dutasteride (Avodart). Those drugs may also decrease the amount of the ejaculatory fluid, no question. But a reduction in orgasm intensity normally doesn't go together with therapy for BPH. Erectile dysfunction does not usually go along with it either, though certainly if somebody has less sex drive or less attention, it is more of a struggle to have a good erection.
How do you determine whether or not a person is a candidate for testosterone-replacement treatment?
There are two ways that 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 those two approaches is far from ideal. Generally men with the lowest testosterone have the most symptoms and men with maximum testosterone possess the least. But there are some guys who have reduced levels of testosterone in their blood and have no symptoms.
Looking purely at the biochemical numbers, The Endocrine Society* believes low testosterone for a total testosterone level of less than 300 ng/dl, and I think that is a reasonable guide. But no one really agrees on a few. It's similar to diabetes, in which if your fasting glucose is above a certain level, they will say,"Okay, you've got it." With testosterone, that break point is not quite as clear.
| *Notice: The Endocrine Society recommends clinical practice guidelines with recommendations for who should and shouldn't receive testosterone therapy. |
Is complete testosterone the ideal thing to be measuring? Or if we are measuring something else?
Well, this is just another area of confusion and great discussion, but I do not think it's as confusing as it is apparently in the literature. When most physicians learned about testosterone in medical school, they learned about overall testosterone, or all of the testosterone in the body. However, about half of the testosterone that is circulating in the bloodstream isn't available to cells. It's closely bound to a carrier molecule called sex hormone--binding globulin, which we abbreviate as SHBG.
The available portion of total testosterone is known as free testosterone, and it's readily available to cells. Though it's only a little fraction of this total, the free testosterone level is a fairly good indicator of low testosterone. It is not ideal, but the correlation is greater compared to total testosterone.
This professional organization urges testosterone therapy for men who have both
- Low levels of testosterone in the blood (less than 300 ng/dl)
- symptoms of low testosterone.
Therapy Isn't recommended for men who've
- Prostate or breast cancer
- a nodule on the prostate that may be felt during a DRE
- a PSA higher than 3 ng/ml without further evaluation
- that a hematocrit greater than 50% or thick, viscous blood
- untreated obstructive sleep apnea
- severe lower urinary tract infections
- class III or IV heart failure.
Do time daily, diet, or other factors affect testosterone levels?
For many years, the recommendation has been to receive a testosterone value early in the morning since levels start to fall after 10 or even 11 a.m.. But the information behind this recommendation were drawn from healthy young men. Two recent studies demonstrated little change in blood testosterone levels in men 40 and older within the course of the day. One reported no change in typical testosterone till after 2 p.m. Between 6 and 2 p.m., it went down by 13 percent, a modest amount, and probably insufficient to influence identification. Most guidelines nevertheless say it's important to do the evaluation in the morning, however for men 40 and above, it probably does not matter much, provided that they get their blood drawn before 5 or 6 p.m.
There are a number of rather interesting findings about diet. By way of instance, it appears that individuals that have a diet low in protein have lower testosterone levels than males who consume more protein. But diet hasn't been studied thoroughly enough to create any clear recommendations.
Within the following article, testosterone-replacement therapy refers to the treatment of hypogonadism with exogenous testosterone -- testosterone that's produced outside the body. Based on the formulation, treatment can lead to skin irritation, breast tenderness and enlargement, sleep apnea, acne, decreased sperm count, increased red blood cell count, and other side effects.
In a recent prospective study, 36 hypogonadal men took a daily dose of clomiphene citrate for at least three months. Within four to six months, each one the men had increased levels of testosteronenone reported any side effects throughout the entire year they had been followed.
Since clomiphene citrate isn't accepted by the FDA for use in males, little information exists about the long-term effects of taking it (including the risk of developing prostate cancer) or whether it is more effective at boosting testosterone than exogenous formulations. But unlike adrenal gland, clomiphene citrate maintains -- and potentially enriches -- sperm production. This makes medication such as clomiphene citrate one of only a few choices for men with low testosterone who want to father children.
What forms of testosterone-replacement therapy are available? *
The oldest form is an injection, which we still use because it's inexpensive and since we faithfully become good testosterone levels in nearly everybody. The disadvantage is that a man should come in every couple of weeks to get a shot. A roller-coaster effect can also occur as blood testosterone levels peak and return to research.
Topical therapies help maintain a more uniform level of blood glucose. The first kind of topical treatment was a patch, but it has a very high rate of skin irritation. In 1 study, as many as 40 percent of men who used the patch developed a red area on their skin. That restricts its usage.
The most widely used testosterone preparation in the United States -- and the one I begin almost everyone off -- is a topical gel. The gel comes in miniature tubes or within a unique dispenser, and you rub it on your shoulders or upper arms once a day. Based on my experience, it tends to be consumed to great levels in about 80% to 85% of men, but leaves a substantial number who don't consume sufficient for it to have a favorable impact. [For specifics on various formulations, see table ]
Are there any drawbacks to using gels? How much time does it take for them to work?
Men who begin using the gels have to come back in to have their own testosterone levels measured again to make certain they are absorbing the right quantity. Our target is that the mid to upper range of normal, which usually means approximately 500 to 600 ng/dl. The concentration of testosterone in the blood really goes up quite quickly, in just a few doses. I normally measure it after 2 weeks, although symptoms may not change for a month or two.