Hormonal Update Volume 3 Number 2

Testosterone Replacement

The hormone testosterone has a reputation for being the essence of a man’s strength and sexuality. The mere mention of testosterone supplementation at the gym makes men sit up and take notice. Touted for producing big muscles, tight abs, an abundance of stamina, not to mention libido to spare, who wouldn’t be interested in a little extra testosterone? Historically hormone replacement therapy has been prescribed predominantly for women, but testosterone may now be changing that. 

Testosterone is an androgen, or male hormone, produced by the adrenal glands, and in the testis in men and ovaries in women. It has an anabolic action in the body, defining and fueling our sexuality, as well as helping build strong bones, muscles and ligaments. Testosterone deficiency in men has been shown to produce symptoms of hypogonadism, a decrease in erectile function and libido. In addition, the most current research has found a connection between declining testosterone production and osteoporosis, decreased muscle mass and strength, reduced food intake, diminished cognitive function, and depression. 

Because testosterone has been given the moniker “hormone of desire”, it has become almost as alluring to women as to men. For women who have suffered a loss of libido because of perimenopausal or menopausal shifts in their hormone levels, the idea of adding testosterone to their replacement therapy and restoring their sexual desire is very appealing. But, testosterone may be important to women for more reasons than sparking their sexuality. Achy joints, thin dry skin, brittle bones, fatigue and depression can all be signs of a low testosterone level in a woman.

In men, testosterone production peaks at approximately age 30, and then begins to decline at a rate of 1% per year. Interestingly, this natural decline seems to parallel an increase in symptoms commonly associated with aging. Look at the Androgen Deficiency in Aging Males or ADAM questionnaire developed by Dr. John Morley of St Louis University. Dr. Morley is an internationally known gerontologist with expertise in all aspects of aging including both male and female menopause, osteoporosis, and nutrition. Dr. Morley developed the ADAM questionnaire as a way of identifying low testosterone in men. It has been proven clinically that answering yes to number one or seven, or any three of the other questions can indicate a testosterone deficiency.

The Androgen Deficiency In Aging Males (ADAM) Questionnaire
All questions must be answered yes or no.

The Physiology of Production

When testosterone is produced and released into the bloodstream a number of things occur. It can travel directly to a cell site as a free hormone, active and ready to do its job. Or, it can enter the bloodstream and bind with one of two proteins - sex hormone binding globulin (SHBG), or albumin. Approximately 50 to 60% of the all the hormone produced in your body binds with SHBG, 35% binds with albumin and the remaining, approximately 5%, remains free.

These proteins act somewhat like storage vehicles for the hormone. SHBG seems to store the hormone permanently, whereas albumin functions more like a bioavailable reservoir. The difference between binding with SHBG and albumin could be compared to the difference between binding something with SuperGlue(tm) or Elmer’s(tm). Once a hormone is bound with SHBG it is difficult to dislodge. On the other hand, when it is bound to albumin it is more loosely bound, allowing the hormone to become free and bioavailable quite easily. So why is it important whether the hormone is bound to a protein or not? Currently, experts believe that the albumin bound testosterone has a significant physiologic function, and should be measured along with the free hormone to determine the reservoir of hormone that is bioavailable. 

The body has a complex built-in mechanism that oversees how much hormone is available to cells at any given time. With SHBG, the protein actually prevents the hormone from interacting with cell receptor sites. The albumin bound and free hormones, on the other hand, are ready, willing and able to be biologically active.

In general, when you are in the prime of life you have enough of the various hormones circulating in your bloodstream to keep your body in tip-top shape. Once hormone levels have declined and you begin having symptoms hormone replacement can help restore optimum hormone levels. However, too much of a supplemental hormone can sometimes cause side effects.

In the case of testosterone, too much can increase a man’s risk for prostate cancer. It can also increase feelings of aggression and irritability. This is why determining your testosterone level before beginning replacement therapy is so important. Of course, the same holds true for a woman when it comes to determining her testosterone level before prescribing replacement therapy. In a woman, too much testosterone can cause excess facial hair and oil production. These are side effects that subside quickly once a testosterone dosage is reduced. But, too much testosterone can also cause side effects that are not temporary, such as enlargement of the clitoris and a lowered voice.

Testing Your Testosterone Level