Testosterone: The Most Important Male Sex Hormone

Testosterone is an anabolic steroid that is secreted from the testes in males and the ovaries in females, with some secretion from the adrenal glands. It’s the primary sex hormone found in males.

With decreasing testosterone come a slew of health problems and concerns. Men tend to lose their sex drive and libido, feel sluggish and lose muscle mass. Men start to notice these changes after the age of 30, with the problems increasing as they get older and older. Adult men’s bodies produce, on average, 40 to 60 times more testosterone than adult women’s bodies. Women, however, are more sensitive to the hormone.


The Science of Testosterone

Testosterone is derived from cholesterol, like other steroid hormones, with the largest amount found in the testes, as it’s produced by the Leydig cells. Testosterone, in much smaller quantities, is also synthesized by the thecal cells in women’s ovaries, the placenta, as well as the zona reticularis of the adrenal cortex in both sexes. The male generative glands, or testes, also contain Sertoli cells which require testosterone for spermatogenesis.

Testosterone affects the entire body by enlarging certain organs, such as the heart, lungs, liver, etc. As the brain enlarges, aromatase, an enzyme, converts testosterone into estradiol, which is responsible for the masculinization of the brain in a male fetus.

The differences between a male and female brain are the results of different levels of testosterone in men and women. In general, the brain of a male is larger than that of a female brain. However, the corpus callosum is much larger in females than in males.

Testosterone Studies

In a study conducted in 1996, there were no effects on mood or behavior from the administration of supraphysiologic doses of Testosterone for 10 weeks to healthy men.

The study found that key cognitive functions affected by testosterone in humans are attention, memory, and spatial ability. Some preliminary evidence indicates that low testosterone levels may be a risk factor for cognitive decline and possibly for dementia of the Alzheimer’s type. This is a key argument for the use of testosterone in anti-aging therapies in Life Extension Medicine. The majority of the studies reference a curvilinear or even quadratic relationship between the testosterone circulating in the body and men’s spatial performance, and they show that both hypo- and hypersecretion of circulating androgens seem to cause negative effects on cognition and cognitively-modulated aggressivity, as mentioned earlier.

Other studies and certain sectors of the media suggest that aggressive behavior occurs with testosterone therapy. Contrary to this belief, aggressive behavior is not typically seen in hypogonadal men who receive testosterone replacement therapy, giving them normal testosterone levels. In fact, it has been shown that aggressive behavior has been associated with hypogonadism and low testosterone levels. Research also shows that supraphysiological and low levels of testosterone and hypogonadism cause mood disorders and aggressive behavior. This shows that eugondal/normal testosterone levels are important for mental well-being.

It is well-known that aging in men causes Testosterone depletion. One of the consequences of this reduced Testosterone has been shown to be an increased risk for Alzheimer’s Disease development (this finding was based on a study by Pike et al, 2006, Rosario 2004).