Testosterone

Men

In adult males approximately 90 to 95 percent of testosterone is produced in the testicles by the Leydig cells, and the remainder is secreted as another product of the adrenals, those small, spectacularly potent glands which sit above the kidneys. (Normal range in men is defined as between 350 and 1000 ng/dl.)

It could be said that Testosterone is to men what Oestrogen is to women.

In a similar way, a man's production of testosterone is reduced as he ages ... the new term for this process is called “Andropause” (cf. “menopause”)

... and Oestrogen in Men

Interestingly, the male body manufactures its own supply of female hormone.

Where does it get it?

It makes it out of that most masculine of all substances, testosterone. An enzyme called aromatase is widely present in the body and converts a certain portion of the male hormone into the female.

When it comes to estrogen, the window of optimum effectiveness in the male body is very small. Estrogen produced by this conversion can actually unlock or displace testosterone at its various cellular receptor sites. Consequently, too much estrogen will switch off activities.

The control mechanism aspect of estrogen can get out of hand as we grow older. Illness, drugs, dietary imbalances, lifestyle and certain aspects of normal aging help accelerate this process and raise estrogen levels to unhealthy heights. One of the first things we notice is that levels of aromatase, the testosterone-to-estrogen converter, increase. This is, in part, because systems for controlling aromatase falter. In addition, methods of eliminating estrogen once it has been created decline. As a result, the typical middle-aged man becomes overestrogenized.

Note: Chrysin, which blocks aromatase, has been successfully used to mitigate the oestrogenising of men. It is usually prepared in cream form as it is not readily absorbed orally.

Testosterone the muscle builder

In our youth, our bodies are protein-forming anabolic machines.

To build up the towering structure of muscle and bone that was the youthful you, your body chiefly employed powerful anabolic hormones, testosterone and human growth hormone to take the amino acids present in the blood after digestion and turn them into protein, which is the very substance of life. So successful was the whole process that in our days of high and happy youth, it was difficult to harm us with anything less traumatic than a speeding bullet.

Muscle Breakdown

In the second half of life, however, the reverse process begins to take charge. This is catabolism, the breaking down of tissue. The stress hormones (e.g. Adrenaline, cortisone) aid this process by turning protein back into amino acids and ultimately converting them to glucose for energy ... hence the loss of muscle tissue.

... and Insulin

Coupled with the reduction in testosterone is an increase in the production of insulin. One problem, though ... as we get older the body uses insulin less effectively - a state called insulin resistance - ultimately resulting in excess insulin production. The body also has less control over its stress hormones and tends to produce more of them quite independently of the demands of insulin. This stress hormone overload is partly the result of testosterone decline. Testosterone has been shown to be an antagonist of the stress hormones: more testosterone, less stress hormone production.

DHEA, another hormone that declines as we age, has also been shown to play an important part in controlling stress hormones (refer to its position in "Hormonal Pathways Involving Adrenal Androgens".)

The evidence to show that high testosterone is associated with lower levels of insulin is, by now, overwhelming. Dr. Elizabeth Barrett-Connor, one of the premier American epidemiologists, has collaborated on a study that demonstrates that testosterone decreases and insulin increases with each decade of life and that, independent of the age of the individual examined, there tends to be a direct relationship between the extent of testosterone decline and the extent of insulin increase. In other words, the more or less opposite curves that the two hormones make when graphed over time are not simply coincidentally related but apparently causally related.

Testosterone and The Heart

Shippen & Fryer, in their excellent book, "The Testosterone Syndrome", make the point strongly that testosterone is heart-protective. Testosterone, by definition, is anabolic (builds protein) ... the heart is a muscle and muscle is almost totally protein. Apart from this obvious benefit, the reduction in testosterone production coincides with ..

Increase in cholesterol and Triglyceride levels
Rising Blood Pressure
Increased Insulin Output
Increased abdominal fat
Increased Oestrogen levels
Decreased energy and strength
Decreased Human Growth Hormone output resulting in loss of energy and vitality
Loss of Libido

"No other single factor in the male body that we know of correlates with more risk factors for heart disease than testosterone," write Shippen & Fryer.

Testosterone Preparations

Creams (5% is common) are `rubbed daily into the sternum or any other thin skinned area. Troches (a type of lozenge) can be placed between the gum and cheek and allowed to dissolve slowly. Strengths of up to 25mg (sometimes higher) are commonly prescribed.

N.B. Ensure hands are washed thoroughly after application of testosterone creams, especially if handling food.

Women

In women, approximately half the testosterone produced comes from the ovaries and about half from the adrenal glands. Some is also created elsewhere in the body by conversion from the adrenal hormone, DHEA. During the menstrual years, these various sources of the male hormone give the average woman a level about one-tenth as high as that of the average male. But, by her mid-thirties, a woman’s adrenal production begins to fall off dramatically, although sometimes not right away. That’s because, as the ovaries begin to fail, the body sends surges of gonadotrophins to promote estrogen production. Frequently, all they can manage to do is increase testosterone, an estrogen precursor (see "Hormonal Pathways Involving Adrenal Androgens"). Thus, there may be a temporary rise in the male hormone.

Oestrogen Replacement

If, at that point, a woman goes on estrogen replacement, however, testosterone will quickly fall. This is yet another reason why a modest replacement dose of testosterone as an accompaniment to estrogen replacement makes very good sense for menopausal women.

Overall, a woman’s levels of testosterone decline by approximately 50 percent in the years after menopause. Perhaps half of this decline is due to the complete shutdown of testosterone production in the ovaries. Equally important, however, is declining production of two other important steroids, androstenedione and DHEA, in the adrenal glands. These two hormones have relatively weak androgenic action of their own, but by a convenient process they are converted to testosterone intracellularly throughout the body - peripheral conversion, as it’s called.

Sex Drive

For a woman to have an optimal sex drive, testosterone levels need to be more or less in the range of 30 to 60ng/dl.

Excessive doses of testosterone can cause growth of facial hair and, in extreme cases, a deepening of the voice. Fundamentally, however, there is no justification for a woman ever taking doses high enough to cause such problems. Testosterone is a natural part of a woman’s body, and the small supplemental replacement doses that a competent physician will prescribe will simply bring her back into her normal range.

Not for All Women

Not every postmenopausal woman is in need of testosterone replacement. Deciding which woman would benefit is done by analysing two types of information: her testosterone levels as determined by blood tests and any symptoms and health problems that have occurred since menopause and that remain troublesome, in spite of estrogen and progesterone replacement therapy.

Women whose testosterone levels are from 10 to 100ng/dl are recorded as being in the normal range. In point of fact, after menopause the range is from 10 to 50ng/dl.

A woman will not have an entirely satisfactory sex drive if her testosterone levels are lower than 30ng/dl.

Supplementation

The easiest is a cream or gel applied to various parts of the body five times weekly. Each gram of the cream should contain 3 to 6 milligrams of testosterone. A very small amount of the cream can be applied two to three times a week to the external genitalia to stimulate sexual response. Women with leaky bladders will find that a milder testosterone formulation - .25 to .5 milligrams of testosterone to each gram of cream - can be applied intravaginally with a vaginal applicator.

Troches, a type of lozenge which dissolves slowly when placed between the cheek and gum is also a very effective means of delivering testosterone and other hormones. Direct absorption (buccal) into the blood stream via the surface capillaries in the mouth, reduces the effect of breakdown in the gut (first-pass effect) and consequently the hormone is delivered more intact.