Frailty is characterized by generalized weakness, impaired mobility and balance and poor endurance. Loss of muscle strength is an important factor in the process of frailty, and is the limiting factor for an individual's chances of living an independent life until death. In men, several hormonal systems show a decline in activity during ageing. Serum bioavailable testosterone and oestradiol, dehydroepiandrosterone and its sulfate, and growth hormone and insulin-like growth factor 1 concentrations all decrease during ageing in men. Physical changes during ageing have been considered physiologic, but there is evidence that some of these changes are related to this decline in hormonal activity. Studies on hormone administration in the elderly appear to be promising. However, until now, hormone replacement has not yet been proven to be beneficial and safe.