When you think of testosterone, what comes to mind? Macho men? Aggressive, impatient, type A behavior? Road rage? Violence?
Testosterone’s role in bad behavior is largely a myth. What’s more, testosterone plays other important roles in health and disease that may surprise you. For example, did you know that testosterone is a key player in prostate cancer? There’s more to testosterone than guys behaving badly.
Testosterone is the major sex hormone in males and plays a number of important roles, such as:
- The development of the penis and testes
- The deepening of the voice during puberty
- The appearance of facial and pubic hair starting at puberty; later in life, it may play a role in balding
- Muscle size and strength
- Bone growth and strength
- Sex drive (libido)
- Sperm production
Testosterone may also help maintain normal mood. There may be other important functions of this hormone that have not yet been discovered.
Signals sent from the brain to the pituitary gland at the base of the brain control the production of testosterone in men. The pituitary gland then relays signals to the testes to produce testosterone. A “feedback loop” closely regulates the amount of hormone in the blood. When testosterone levels rise too high, the brain sends signals to the pituitary to reduce production.
|Did You Know?|
|Testosterone is synthesized in the body from cholesterol. But having high cholesterol doesn’t mean your testosterone will be high. Testosterone levels are too carefully controlled by the pituitary gland in the brain for that to occur.|
The Perils of Too Much Testosterone
Having too much naturally-occurring testosterone is not a common problem among men. That may surprise you given what people might consider obvious evidence of testosterone excess: road rage, fighting among fathers at Little League games and sexual promiscuity.
Part of this may be due to the difficulty defining “normal” testosterone levels and “normal” behavior. Blood levels of testosterone vary dramatically over time and even during the course of a day. In addition, what may seem like a symptom of testosterone excess (see below) may actually be unrelated to this hormone.
In fact, most of what we know about abnormally high testosterone levels in men comes from athletes who use anabolic steroids, testosterone or related hormones to increase muscle mass and athletic performance.
Problems associated with abnormally high testosterone levels in men include:
- Low sperm counts, shrinking of the testicles and impotence (seems odd, doesn’t it?)
- Heart muscle damage and increased risk of heart attack
- Prostate enlargement with difficulty urinating
- Liver disease
- Fluid retention with swelling of the legs and feet
- Weight gain, perhaps related in part to increased appetite
- High blood pressure and cholesterol
- Increased muscle mass
- Increased risk of blood clots
- Stunted growth in adolescents
- Uncharacteristically aggressive behavior (although not well studied or clearly proven)
- Mood swings, euphoria, irritability, impaired judgment, delusions
Too Little Testosterone
In recent years, researchers (and pharmaceutical companies) have focused on the effects of testosterone deficiency, especially among men. In fact, as men age, testosterone levels drop very gradually, about 1% to 2% each year — unlike the relatively rapid drop in estrogen that causes menopause. The testes produces less testosterone, there are fewer signals from the pituitary telling the testes to make testosterone, and a protein (called sex hormone binding globulin (SHBG) increases with age. All of this reduces the active (free) form of testosterone in the body. More than a third of men over age 45 may have reduced levels of testosterone than might be considered normal (though, as mentioned, defining optimal levels of testosterone is tricky and somewhat controversial).
Symptoms of testosterone deficiency in adult men include:
- Reduced body and facial hair
- Loss of muscle mass
- Low libido, impotence, small testicles, reduced sperm count and infertility
- Increased breast size
- Hot flashes
- Irritability, poor concentration and depression
- Loss of body hair
- Brittle bones and an increased risk of fracture
Some men who have a testosterone deficiency have symptoms or conditions related to their low testosterone that will improve when they take testosterone replacement. For example, a man with osteoporosis and low testosterone can increase bone strength and reduce his fracture risk with testosterone replacement.
|Did You Know?|
|There are times when low testosterone is not such a bad thing. The most common example is probably prostate cancer. Testosterone may stimulate the prostate gland and prostate cancer to grow. That’s why medications that lower testosterone levels (for example, leuprolide) and castration are common treatments for men with prostate cancer. Men taking testosterone replacement must be carefully monitored for prostate cancer. Although testosterone may make prostate cancer grow, it is not clear that testosterone treatment actually causes cancer.|
Currently, testosterone therapy is approved primarily for the treatment of delayed male puberty, low production of testosterone (whether due to failure of the testes, pituitary or hypothalamus function) and certain inoperable female breast cancers.
However, it is quite possible that testosterone treatment can improve symptoms in men with significantly low levels of active (free) testosterone, such as:
- Generalized weakness
- Low energy
- Disabling frailty
- Problems with sexual function
- Problems with cognition.
The Bottom Line
Testosterone is so much more than its reputation would suggest. Men and women need the proper amount of testosterone to develop and function normally. However, the optimal amount of testosterone is far from clear.
Checking testosterone levels is as easy as having a blood test. The difficult part is interpreting the result. Levels vary over the course of the day. A single low level may be meaningless in the absence of symptoms, especially if it was normal at another time. We need more research to know when to measure testosterone, how best to respond to the results and when it’s worthwhile to accept the risks of treatment.
If you are ready to check your testosterone levels at any of our 3 clinic locations make an appointment by calling 817-632-5400. You can also fill out this form and one of our booking specialist will contact you: https://form.jotformpro.com/50135677439966