HORMONES & MEN: THE FACTS

Important Considerations around Testosterone Evaluation and Treatment:
After the age of 35, the average testosterone level decreases at a rate of approximately one percent per year. However, if only absolute testosterone levels are evaluated, many patients with andropause will be missed. There may be an increased level of sex hormone-binding globulin that binds the testosterone and makes less of it available to the tissues. Also, as men get older, the daily rhythm to the secretion of testosterone changes. Younger men have higher testosterone in the morning, which then decreases as the day wears on. In older men, this curve is flattened, leading to steady low levels of testosterone throughout a 24-hour period.

Here are some issues regarding testosterone that are important to remember:

• It is not yet known what level of serum testosterone defines a deficiency in older men. Generally, it is accepted that two standard deviations below the normal values for young men is considered abnormal.
• A man may have large variations in his serum testosterone levels over time. Since he may have normal testosterone levels one day and have decreased testosterone levels the next, it is important to look at hormone levels over a period of time.
• In older men, affected organs may respond differently to androgens.
• Not all men will need the same level of testosterone to maintain proper function of their brain, bone, prostate, or muscle cells.

Therefore, it would be incorrect to say that there is one standard level of testosterone that should be achieved by all men. Rather, the patient and the physician work together to find the level of testosterone that is most effective for the particular patient.

Testosterone Replacement Therapy:
Therapy for andropause is often very effective. Treatment goals include restoration of sexual functioning, increased libido, increased sense of well-being, prevention of osteoporosis by optimizing bone density, restoration of muscle strength, and improved mental functioning. Biochemically, testosterone replacement should aim not only to reach normal levels of serum testosterone, but also to normalize levels of those secondary hormones that are affected by testosterone levels. These include DHT and estradiol.

Current treatment options include testosterone injections  and transdermal (through the skin) gels. However, at this point, the vast majority of testosterone replacement is done through the skin. This method has a number of advantages:

• It is easy to apply.
• It is relatively safe with low incidence of side effects.
• It more closely mimics the natural daily rhythm, with higher levels of testosterone delivered in the morning and decreasing levels delivered as the day progresses.

Efficacy:
Several studies have been conducted involving hormone replacement therapy in men. Unfortunately, at this point, we are approximately 20 years behind the studies of hormone replacement therapy of postmenopausal women, and many of these studies are preliminary. However, they do point to a number of definite benefits of testosterone replacement:

• Improved sexual function: In general, testosterone has proved relatively effective for men who have low libidos (desire levels). Libido is believed to be significantly hormonally dependent.
• Improved erectile function: Erectile function is a more complicated phenomenon. There is a proven significant interaction between the hormonal level and sexual functioning, but many other factors are also involved. Newer studies seem to show that men and women will respond more effectively to traditional treatments for sexual dysfunction (including oral medications and injections) if they have adequate testosterone levels.
• Improved mood: In recent studies, older men on testosterone seem to report an improved sense of well-being and an overall improvement in mood when compared with similar men who have received a placebo. Energy levels often also improve.
• Improved body composition and strength: Studies evaluating body composition have consistently shown that with testosterone therapy, there is a decline in body fat, an increase in lean body mass (largely muscle mass), or an improvement in both. Several studies also indicate that muscle strength improves, affecting the upper and lower extremities such as hands, arms, and legs.
• Increased bone density: Low bone density or osteoporosis is an increasing problem in men. Men with osteoporosis have a relatively high incidence of bone fractures and, most significantly, hip fractures. Hip fractures in older men are closely associated with disability and death. Testosterone therapy has been shown to increase bone mineral density, especially in the spine. It has also been shown to decrease the rate at which bone is lost.
• Improved cardiovascular system: Men overall have a higher incidence of cardiovascular disease and cardiovascular-related deaths than women. It is not known whether this is due to the beneficial effects of female hormones (estrogens) or lifestyle patterns of women, or whether male hormones play a negative role in the cardiovascular system. However, it is believed that androgens may help lower the risk factors for cardiovascular disease, including serum lipoprotein profiles, vascular tone, platelet and red blood cell clotting parameters, and the process of atherosclerosis.

Early studies have shown that testosterone therapy may decrease platelet aggregation (clumping) and dilate blood vessels. This would have a positive effect on the cardiovascular system. Interestingly, and very importantly, testosterone therapy in older men has led to a decrease in total cholesterol levels. It has also led to a decrease in low-density lipoprotein cholesterol (bad cholesterol levels). These changes, however, have been modest. There has been no significant change in high-density lipoprotein cholesterol levels (HDL or good cholesterol levels) as a result of testosterone therapy. Basically, the effects of androgens on cardiovascular disease are unknown.

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