Prince Henry's Institute at Monash Medical Centre is seeking healthy but overweight men to take part in a study on the effects of testosterone treatment on body fat and heart disease.

Non-smokers, aged between 40 and 70 years, are needed for a series of clinical trials on the link between testosterone levels, fat and the risk of heart disease in ageing men.

Dr Carolyn Allan and Professor Rob McLachlan from Prince Henry's Institute have shown that men over the age of 55 with low testosterone may have a greater risk of heart attack.

Men with extra abdominal fat are also at greater risk of developing cardiovascular disease.

'We know men with heart disease are likely to have low testosterone levels but we don't know which comes first—the heart disease or the low testosterone.

'We now want to trial the effectiveness of testosterone treatment in men who are carrying extra abdominal fat,' said Dr Allan.

Dr Allan said she believed testosterone treatment might be beneficial for ageing men with low levels of testosterone who are overweight and at risk of heart disease.

'We have shown that if men lose weight, their testosterone levels increase.

'We also know when men with a lot of abdominal fat are given testosterone, their fat decreases.'

The hormonal changes that occur in men as they age are often referred to as the ill-defined andropause or male menopause.

Testosterone levels in men decline by about one to two per cent from the age of around 40.

Testosterone deficiency affects one in 200 men under the age of 60 and increases with age.

Low levels of testosterone can impact muscle mass, body composition, bone and reproductive function.

Symptoms may include poor concentration, tiredness, irritability and a reduced sex drive.

•          For more information contact Anna Zamojska or Elise Forbes at Prince Henry's Institute on 9594 3087 or 9594 3554.