DR MALCOLM CARRUTHERS INTERVIEWED BY PATRICK HOLFORD

Around a third of men in the 40 to 69 age group complain of a range of symptoms that commonly include, in order of importance, loss of libido, erectile dysfunction (inability to get or maintain an erection), depression and worsening memory and concentration. These are the classic symptoms of the male menopause, called the andropause and are associated with testosterone deficiency. Despite years of research, pioneered in Britain by Dr Malcolm Carruthers, who wrote The Testosterone Revolution, many doctors still deny the existence of the male menopause.

What are the main symptoms of the andropause?

On the sexual front the most common symptoms are loss of potency, loss of sex drive and loss of morning erections. The most common psychological symptoms are mild to moderate depression, irritability and an early reduction in memory and mental concentration. Physical symptoms related to the andropause are similar to those experienced by women, including joint aches and pains, dry and thinning skin, occasionally sweating at night and the feeling that the body's thermostat has gone wrong inducing flushing.

How do you find out if you are low in testosterone?

On the whole symptoms are a much better guide than the blood tests. If one relies purely on the blood testosterone level (a score below 12nmol/l or 350NG/DL US) research shows that 75% of cases of the andropause would be missed. One of the reasons for this is that the more useful measure is the amount of 'free' or available testosterone. A doctor should measure both your testosterone level and the level of Sex Hormone Binding Globulin(SHBG), which binds to, and hence inactivates testosterone. By knowing these two figures you can work out the 'free' testosterone. Salivary testosterone does also correlate with free testosterone however the use of this test is not yet fully accepted. This alone, however, is not enough to make a diagnosis because there are many other risk factors that interfere with testosterone, for example, interfering with the testosterone receptors.

What are the risk factors?

The age distribution peaks at 55, but often men suffer symptoms for 3-5 years, so time of onset is similar to female menopause at age 50. If a man has had an infection, particularly adult mumps, and possible other viral infections such as glandular fever, especially during puberty when the testes are establishing its own immune identity, this can cause damage to fertility and testosterone production. A man may have enough testosterone to father children but not to carry him healthily into old age. Sexually transmitted diseases, such as non-specific urethritis, can damage the testes as can physical blows to the testes, including vasectomy. Stress also has a major impact. Basically, anything that puts a man down will put testosterone down - loss of a partner, job, loss of sleep, lots of traveling and high stress jobs. Being overweight, or having insulin resistance or diabetes, all increase oestrogen dominance, which inhibits testosterone.

Can women suffer from testosterone deficiency?

I work primarily with men, however more and more attention is being paid to testosterone levels in women. A woman's body produces four times more testosterone than oestrogen. In fact, women's oestrogen is made from testosterone. We know, for example, than declining oestrogen levels in the brain can lead to poor memory and that giving women testosterone can raise oestrogen levels in the brain. Hence, one can expect that a woman with low testosterone would experience all the symptoms associated with oestrogen deficiency including loss of sex drive and bone mass density. Progesterone, the other key female hormone, is a precursor for both oestrogen and testosterone.

If a man is diagnosed with the andropause on the basis of both symptoms and free testosterone levels what's the cure?

If you test low there's an increasing range of testosterone treatments including pills, pellets, patches and more recently transdermal creams. Testosterone pellets, which last for six months, are a bit like putting a tiger in your tank. Testosterone injections are a bit of a roller coaster. I prefer oral preparations or Gels. In the UK look out for Testogel and, in the US, Androgel. Of course, it's important to also make the lifestyle changes that reduce risk. But my attitude is that if a man has lost his enthusiasm for life and love, you can often kick-start by correcting testosterone deficiency and then they have more enthusiasm to reduce stress, alcohol and weight and change to a more holistic lifestyle.

Are there any downsides to testosterone therapy?

Firstly, I recommend physiological levels of testosterone and prefer methods of delivery, including oral, that give a steady supply, equivalent to that which the body would naturally produce. Given the well proven increased risk of breast cancer with oestradiol and synthetic progestins one is right to look carefully at any possible increased risk for prostate cancer, which is very prevalent among men. To date there is no real evidence that testosterone therapy causes prostate cancer. We have followed 1,500 relatively high risk men for up to fifteen years, of which 8 developed prostate cancer during that time. That is actually a lot lower than the current national average. Although I see no evidence that testosterone therapy could initiate prostate cancer it could conceivably aggravate it. For this reason I always measure a man's Prostate Specific Antigen (PSA) which is a marker for prostate cancer. If it is raised then a diagnosis is made on the basis of ultrasound study and/or biopsy. Screening for older men is a good idea anyway. I've identified early stages prostate cancer, which can then be treated, in 12 patients to date by doing this. There are now proper ground rules and guidelines for giving testosterone therapy we give physiologically equivalent amounts and I spend my time teaching doctors. You can find a suitably informed doctor by visiting the website of The Andropause Society www.andropause.org.uk

What about diet?

A higher protein diet tends to put up testosterone, and put down sex hormone binding globulin, so you need enough protein. A strict vegetarian or vegan diet is more likely to be associated with lower testosterone levels. Also, very high fiber diets tend to raise SHBG, which binds to testosterone making it unavailable. High alcohol consumption is another risk factor. If a man has had a period of heavy drinking in their life in time their liver may forgive and forget but the testes, it seems, harbour grudges.