Testosterone and the brain.
Your thinking abilities and general sense of well-being, including your mood, energy level and sense of vitality, and sexual drive or libido are all affected by testosterone.
Testosterone and muscle.
Testosterone creates muscle cells and causes them to grow in size and strength.
Testosterone and fat.
Testosterone has been shown to reduce body fat, particularly in the midsection and chest. The result is an improvement in lean body mass.
Testosterone and bones.
Testosterone helps prevent the normal bone destruction of aging and actually improves bone density. This reduces the risk of osteoporosis and fractures.
Testosterone and the heart.
Testosterone can inﬂuence cardiovascular risk factors indirectly through its effect on the amount of fat in your body, and there is evidence it beneﬁts the heart directly. It may help open the coronary arteries, and possibly improve cardiac function in people with heart disease and heart failure.
Testosterone and sexual organs.
Testosterone is important for proper erectile function, and it can improve the quality of erections. These physiological aspects are separate from the effects testosterone has on the brain and your libido, but are related and are important for the normal enjoyment of life.
- Irritability or unexplained negative mood
- Loss of motivation
- Anxiety or increased pessimism
- Increased fatigue, low energy or diminished sense of well-being
- Difﬁculty concentrating, lack of focus, forgetfulness and loss of memory
- Feeling that you have lost your edge or passed your peak
- Insomnia or poor sleep
- Joint pain
- Lacking desire (low libido) or pleasure in sex
- Decreased ability to perform sexually
- Erections that are less strong
Although many of these symptoms may be simply a result of normal aging, our is to evaluate any signs or symptoms of low testosterone, and then to see how they correlate with your hormone levels.
- Increased energy
- Increased bone density
- Reduced risk of obesity, diabetes and metabolic syndrome
- Reduced risk of cardiovascular disease
- Reduced risk of osteoporosis
- Reduced body fat
- Reduced risk of anaemia
- Increased lean body mass and muscle strength
- Increased libido
- Increased sexual enjoyment
- Increased satisfaction with erections
- Increased sexual activity
- Improved mood and sense of wellbeing
- Improved cognition and memory function
Aromatase: One of the most important factors that affect testosterone levels and the ratio between testosterone and estrogen is the aromatase enzyme. Aromatase converts testosterone to estrogen, further depleting free testosterone levels and increasing estrogen levels.
Obesity: Obesity and associated hyperinsulinemia suppress the action of luteinizing hormone (LH) in the testis, which can significantly reduce circulating testosterone levels, even in men under the age of 40. In addition, increased belly fat mass has been correlated with increased aromatase levels.
The vicious circle of low testosterone and obesity has been described as the hypogonadal/obesity cycle. In this cycle a low testosterone level results in increased abdominal fat, which in turn leads to increased aromatase activity. This enhances the conversion of testosterone to estrogens, which further reduces testosterone and increases the tendency toward abdominal fat.
Sex hormone-binding globulin (SHBG): Most testosterone circulating in the bloodstream is bound to either sex hormone-binding globulin (SHBG) (60%) or albumin (38%). Only a small fraction (2%) is unbound, or “free”.
Testosterone binds more tightly to SHBG than to albumin. Consequently, only albumin-bound testosterone and free testosterone are absorbable forms of testosterone, which allows tissues to carry out the actions of the essential hormone. Thus the body’s ability to use of testosterone is influenced by the level of SHBG.
Aging men experience both an increase in aromatase activity and an elevation in SHBG production. The net result is an increase in the ratio of estrogen to testosterone and a decrease in total and free testosterone levels. It is crucial that this skewed ratio be balanced.
Liver Function: The liver is responsible for removing excess estrogen and SHBG, and any decrease in liver function could exacerbate hormonal imbalances and compromise healthy testosterone levels. Thus it is important that aging men also strive for optimal liver function.
The so-called “normal” levels of testosterone in older men reflect population averages. We believe that most aging men would prefer not to accept the loss of youthful vigor as normal. Instead, we suggest that a more valid optimal level for all men would be in the reference range used for men aged 21 to 49 years, and that any supplementation should aim to restore hormone levels to that range.
When measuring testosterone levels, it is critical to determine the levels of both free and total testosterone to understand the cause of any observed symptoms of deficiency.
It is also important to remember that blood levels of both free and total testosterone vary widely among individuals, making it difficult to establish a general baseline on which to prescribe a standardized treatment protocol. However, levels are quite consistent within individuals, and thus it is important that men have multiple tests over time to determine trends and individual thresholds for treatment.
Finally, during the initial testing, it is also imperative to test estrogen levels. Many of the unwanted effects of male hormone imbalance are actually caused by an elevated estrogen level relative to low testosterone levels (the estrogen/testosterone ratio).
- Testosterone therapy in hypogonadal men results in sustained and clinically meaningful weight loss
- Testosterone therapy for low sexual interest and erectile dysfunction in men: a controlled study
- Hypogonadism and erectile dysfunction: the role for testosterone therapy
- Androgen Therapy Improves Insulin Sensitivity and Decreases Leptin Level in Healthy Adult Men With Low Plasma Total Testosterone
- Testosterone Therapy in Adult Men with Androgen Deficiency Syndromes: An Endocrine Society Clinical Practice Guideline
- Guideline for Male Testosterone Therapy: A Clinician’s Perspective