What is it?
Testosterone is a hormone (or steroid) that is found in both men and women, at varying levels and stages of development. Like other hormones, it is produced by specific glands in the body and circulates in the bloodstream to affect organs or tissues at other sites. In men testosterone is produced in the testes and is controlled by the Pituitary gland in the brain; small amounts of Testosterone are also produced by the adrenal gland in the kidneys. Testosterone is one of the most important in the group of hormones called androgens.

Testosterone affects male sexuality and is important in young men for the development of major organs, muscles, bone, hair, voice, and genitals and influences characteristics such as skin glands, sexual behavior, libido, and sperm maturation. In fact, almost every organ system in the body requires testosterone to maintain optimum function.

In women, testosterone is produced in the adrenal gland and the ovaries at approximately one-tenth of the level found in men. In both men and women, testosterone production is at its peak during late teens and early twenties.

What does it do?
Transported by the circulatory system, testosterone affects many areas such as the nervous and cardiovascular systems (including the heart), the metabolism and internal body chemistry, and clearly has a role in the creation of desire for sexual activity.
In men, testosterone plays an important role in sexual functioning and behavior.
In women, its role is less clearly understood, however it appears to be converted into estrogen in order to activate the brains sex receptors.

How does testosterone affect sexual functioning?
Testosterone production is significant during puberty for normal growth and development, and continues to play a role in sexual activity, sperm production, sexual drive and sexual performance. As men age (from about 40 years) testosterone levels may begin to gradually decline. Evidence suggests however, that if a man’s testosterone level is within the normal range, it is unlikely to produce major changes in sexual functioning.

How do you test testosterone levels?
Low testosterone levels may produce symptoms such as tiredness or loss of libido, however this can only be diagnosed through appropriate blood tests. A hormone specialist known as an endocrinologist is the best person to determine whether you have a testosterone deficiency. To be referred to an endocrinologist you first need to discuss your concerns with your GP.

HIV/AIDS and Testosterone
People who are diagnosed with HIV may experience changes in testosterone levels. If you have HIV and are experiencing symptoms such as unwanted weight loss, muscular changes, not feeling sexual/decreased libido, you may wish to explore this as a possible cause with your physician.

Treatments for Testosterone Deficiency
Researchers are not in agreement about when testosterone levels diminish, and as changes in testosterone levels occur naturally over the day, monitoring levels in the blood is advisable before considering supplementation.

Replacement of testosterone can be given to men who are not producing high enough levels of testosterone. If a deficiency is caused by damage to the testes, then fertility is likely to be affected and requires further exploration. If the deficiency is caused by problems with the pituitary gland, treatment with injections to raise the pituitary hormones may be required.

Testosterone can be administered by several delivery methods such as pills, skin patches, injections and implants. All require prescription and close monitoring by a specialist, as this remains a fairly new area of medicine/research and even the experts cannot yet agree on the exact level of deficiency at which testosterone replacement should commence.

Testosterone and the Prostate
The growth of the Prostate gland is controlled by androgens. The most important androgen in men is testosterone, which changes to another androgen called dihydrotestosterone (DHT) to stimulate prostate growth.
The close location of the prostate around the urethra means that any enlargement of the gland can narrow the outflow from the bladder. If the prostate grows too large, it may slow or even stop the flow of urine. Due to this fact, it has been agreed that testosterone replacement therapy is not recommended in men with a history of prostate problems.
Men on Testosterone Replacement Therapy should be regularly checked by their GP to ensure that no abnormalities occur in the growth of their prostate.

Testosterone and Sexual Desire
When men are young, their testosterone levels are at their peak. As men get older, their testosterone levels naturally diminish, although some degree of testosterone production continues throughout a man’s lifetime. Studies have shown that lower testosterone levels do not necessarily mean reduced sexual drive or capacity. Through testosterone replacement, older men can undertake to restore the sexual vitality of their youth. However, human sexuality is complex and involves a multitude of factors such as general health, emotional and psychological. Testosterone replacement may provide short term increased sexual drive and enhanced sexual performance, but the long-term effects are not clearly known and the risk factors should be considered.

How is low testosterone treated?

Low Testosterone is treated by supplementing your bodies supply of testosterone with medicines containing testosterone. Testosterone injections, implants, capsules and patches are available in Australia. Each method of delivering testosterone has its advantages and disadvantages, Patient convenience, familiarity and cost can determine the most appropriate type of treatment for you.

Some of the types of testosterone therapy available are;

Testosterone injections ( Sustanon, Primoteston )

Testosterone injections of 1ml are given into the muscle, usually the buttock, every 2 to 3 weeks, depending upon the dose needed and the response achieved. Injections of 250mg are standard treatment, although lower doses ( 100mg ) may be used.. Following injection levels of testosterone tend to be higher than normal and then slowly diminish over time, some men are sensitive to these wide variations in testosterone levels across the weeks resulting in moodiness. Others find the injections painful, and for these patients alternative delivery methods should be considered. As the testosterone is dissolved in an oily base, it ought to be at room temperature to make injection easier.
Testosterone injections should be avoided in men with bleeding disorders, including those men taking anti-coagulants ( blood thinning medication ).

Testosterone patches ( Androderm)

Testosterone is available in patches that are applied at night and worn constantly to allow testosterone to be absorbed through the skin. The normal dose is a single 5mg patch but 2.5mg patches are also available to allow some dose adjustment. The patches are applied to the back, arms, abdomen or buttocks.
The advantage of this type of treatment is that it more closely follows the bodies normal pattern for testosterone. The disadvantage is that about 10% of young men and 20% of older men develop a skin rash when using the patches. This can sometimes be avoided by the use of a cortisone cream ( Aristocort  cream, 0.02% triamcinolone ) under the patch.

Testosterone implants

Small ‘pellets’ ( about 1cm in length and each containing 200mg of testosterone ) can be placed under the skin of either the abdomen or the buttock. Doctors experienced in this technique must perform the implanting procedure, which is done using local anaesthetic. Most men will need three or four 200mg pellets implanted each time. The implants produce normal serum testosterone levels over a long period and last between four and six months.

Unfortunately about 10% of the pellets work their way to the surface of the skin and are eventually pushed out. Because of the long duration of action it should be used with caution in older men.

Oral testosterone undecanoate ( Andriol)

These 40mg capsules must be taken with fluid that contains fat ( for example, milk ) to help the absorption. One or two capsules are normally required three times per day. The testosterone levels achieved with this form of treatment usually do not fully replace the testosterone levels and are usually only chosen when a man is unable to tolerate other forms of treatment. However, if a man has had low levels of testosterone for a long time, then the capsules may be an appropriate way to begin treatment slowly.