Hormone replacement therapy (HRT) for men relies on giving supplements of the male hormone testosterone. Overall this causes very few major side effects but sometimes problems can develop for a variety of different reasons:

• problems because of the hormone itself: testosterone can cause the body to retain an excess of fluid which may lead to some increase in weight and swelling of the ankles. It can sometimes also cause headaches and may lead to a reduction in fertility, making it more difficult to conceive.

• problems from other illnesses: because of the tendency for testosterone to cause fluid retention HRT should be very carefully watched in men who already have heart disease or high blood pressure (hypertension). Also HRT should be avoided in men with prostate cancer as it could make the condition worse.

• problems from the way HRT is given: the main complication here is when skin patches are used to give the HRT. These can cause skin reactions (irritation, soreness or rashes) in about half of the men who use them.

• problems with getting the dose right: sometimes it can be quite difficult to get a steady level of HRT over a period of time and these changes in levels may cause temporary feelings of depression and tiredness and may also lead to increases or decreases in libido (sexual interest and activity) at different times.

As with any type of treatment the benefits and drawbacks vary from person to person. Many men find HRT very helpful but some do find that the minor complications and inconvenience of taking the therapy are not worthwhile and do not continue with it.