Serum concentrations of dehydroepiandrosterone (DHEA) and its sulfate ester (sDHEA) decrease dramatically with age in parallel with the appearance of age-related health problems, leading to the suggestion that DHEA replacement therapy may be beneficial in older patients. Daily oral doses that restore sDHEA levels to the values seen in young adults are well tolerated in the short-term (6 months to 1 year) and seem to have a positive although modest beneficial effect on bone in elderly women, particularly those with low pretreatment sDHEA levels. This effect seems ascribable to both decreased bone resorption and increased bone formation, which are probably related mainly to conversion of DHEA into active sex steroids, i.e., estradiol and testosterone; this explains why there is no effect on bone in men, whose testes continue to produce testosterone throughout life. Other mechanisms of action, including an increase in insulin growth factor-1, may be operative also. DHEA cannot be recommended as a treatment for osteoporosis at present given the absence of studies evaluating possible efficacy in reducing the fracture rate and possible long-term side effects.