Losing your mind, your muscles and the zip in your drive? Vincent Leong of HealthAnswers checks out what it means to replace the testosterone you've lost.

Some people believe that testosterone is the essence of manhood, the substance in men that make them presidents, fighter pilots, racecar drivers. They say it is the amazing hormone that allows some men to build corporate empires, and to stay "up" all night. But is testosterone really all that and more? Or is it the most over-rated hormone that may bring about very real adverse effects if medically topped-up as it drains when men age? Now that (HRT) is widely acceptable for post-menopausal women, is it a realistic option for men reaching mid-life, and going through -- the male version of menopause?

What Is Testosterone?
Testosterone is an androgen, a male hormone, produced mainly in the testes in men. Small amounts of testosterone is also produced in the adrenal glands in both men and women. The adrenals are located above each kidney.

Both the adrenals and the testicles belong to the endocrine system, which secrete hormones directly into the bloodstream. Our body has a natural feedback system whereby a dip in the level of a specific hormone will automatically trigger the glands to secrete more of it.

What Happens When You Age?
As a woman reaches about 50 years of age, her body stops producing the female hormone oestrogen. This oestrogen deficiency in her body, commonly known as menopause, brings about hot flushes; sleep disturbances, depression, and loss of libido. She may experience dryness in her vagina and pain during sexual intercourse. She is also likely to be more prone to osteoporosis, and cardiovascular and Alzheimer's diseases.

Similarly for men, the level of testosterone declines when they reach the age of about 40. However, the physical and psychological effect this drop in hormone level has on men is not as clear.

A consultant urologist comments: "We do know that there is a decline of about 1 percent of testosterone level in men as they age, or about 10 percent per decade, after 40 years of age."

Regarding the effects of the decrease in testosterone in ageing men, he adds: "We can group the effects of testosterone deficiency into: musculor-skeletal; sexual function; and moods and well-being. Testosterone decline may result in loss of muscle mass and bone density and increase in fat component. There may be loss of libido and easy fatigability in sexual function. And depression, loss of confidence, plus lethargy too have been attributed to testosterone decline."

Measuring Testosterone
However, experts are not sure how much of changes in these three areas in middle-aged men can be attributed to a drop in testosterone levels in the body. After all, mood or sexual interest is really difficult to measure clinically.

"Most men at that age have some medical problems," our consultant comments. "And any one of these medical problems can affect a man's sense of well-being, their sexual function, erectile function. Also events in life like the lost of independence and retirement can create a sense of lethargy or depression too."

One study done on a group of men at the age of 75 revealed that half of them have testosterone levels similar to men in their 30s. One quarter of them have testosterone levels above those of men in their 30s, while another quarter of them have testosterone levels below that of men in their 30s. Amongst the group of men with the lowest testosterone levels, not all will experience effects on their muscular-skeletal, sexual function or mood/well-being.

Only 25 percent of aged men has low testosterone levels, and of these men, not all of them are suffering from negative effects of testosterone loss in the three areas.

Testosterone levels are not only hard to determine in men, testosterone levels also vary throughout the day.

It is recommended that serum testosterone be measured before eleven in the morning. it is possible to measure either total testosterone or free testosterone level. However, what is the accepted normal level of testosterone in older men has not been agreed upon.

The definition of normal level of testosterone for men in different age groups has not been standardised. So, not only is testosterone level different among men of different age groups, they also vary among men of the same age group.

Professor B Lunenfeld, of the Faculty of Life Sciences at Bar-llan University in Israel, who is a world-renowned scientist in the field of endocrinology and president of the International Society of the Study of the Aging Male (ISSAM), tells HealthAnswers: "Each one of us has a different threshold level for testosterone. Therefore it is very difficult to define hypogonadism [drop in hormone secretion from the sex glands] in the ageing population."

Is Testosterone Replacement The Answer?
One thing most medical experts agree upon is that testosterone is responsible for building muscle mass and increasing skeletal density. Nevertheless, experts are not in agreement regarding testosterone's other "wondrous effects" on men.

In the United States, the sales of pills, powders, bars and beverages - many which contain one type or another hormone enhancing chemicals -- promoted to boost athletic performance reached US$1.26 billion in 1997.

Proponents of androstenedione argue that it can signal the body's endocrine system to produce more testosterone and other hormones, resulting in an elevated level of the male hormone to allow athletes to train harder and recover more quickly.

Dr Todd B. Nippoldt, an endocrinologist at Mayo Clinic disagrees. He says there are few research that supports this claim: "There's not even an answer to the question: 'What does it do?' There just isn't enough good published research to back up the claims that if you take andro, you'll see a 300 percent increase in testosterone levels."

The impact of this type of therapy on athletic performance is is being debated, but it is quite evident that it does build muscle mass. But when it comes quality-of-life issues, including sexual functions and general well being, studies are not conclusive.

A man getting supplemental testosterone may feel that he is regaining prowess in sex, but this can be due to his improved confidence or improved physique. We do know that testosterone itself is able to increase libido, but it does not difrectly affect erectile function. As for general well being, it is something that can be affected by many factors, and is difficult to measure.

At this point in time, there is not enough evidence to proof that if we perk up testosterone level, it will improve the quality-of-life in men.

Even if there are studies on the levels of testosterone and the effects of this variation has on ageing men, it does not represent men of all culture, living in different in different environment, on different parts of the globe.

The Risks
Doctors have been prescribing testosterone replacement, or other hormone replacement treatment, to patients for many medical conditions. However, when HRT is not carefully administered, or when testosterone levels are too high, it can spell real trouble.

Some known side effects of overly high testosterone levels include acne, nausea, vomiting, or diarrhoea. Some people experience pain, redness, or swelling at injection site; yellowing of skin or eyes; dark urine; change in emotions or behaviour. Men may have frequent or prolonged penis erections or enlarged breasts; and women may have deepening of voice, change in menstrual periods, increase in facial hair, or hair loss.

Testosterone can to benign prostate enlargement and prostate cancer. We know for sure that testosterone can promote the enlargement of the benign gland, and it is also involved in the growth of prostatic cancer. A man contemplating taking testosterone supplement should have a thorough examination by an urologist to ensure that he does not have prostate cancer.

Even then, latent prostate cancer, or hidden cancer at its beginning stage, may not be detectable by investigation methods currently available.

Prostate cancer can take years to grow. Testosterone replacement studied so far is mostly up to a year of follow-up and that may not be a long enough time to detect any prostate cancer growth if it happens.

In addition, testosterone is known to affect the cardiovascular system. Studies suggest a testosterone boost may cause a tromboembolic effect -- the formation of blood clot - promoting obstruction of blood vessels.

Ultimately, it's advisable that any man with the intention to get testosterone supplement be clear about the risks he is taking. He can then be well informed as he weighs the potential benefits with the risks involved.

Doctors and patients have to be careful when considering testosterone replacement. He tells doctors that HRT should only be administered to men who have shown objective evidence of hormone deficiencies. They have to take into consideration other possible causes of dysfunction of the endocrine system such as acute, chronic or inter-current diseases. Finally, HRT should only be administered by physicians with basic knowledge and clinical experience in diagnosis, treatment and monitoring of endocrine deficiencies.

Date reviewed: 21 March 2005