Dehydroepiandrosterone (DHEA) and its ester dehydroepiandrosterone sulphate (DHEAS) are produced by the adrenal glands. These hormones are inactive precursors that are transformed into active sex steroids in peripheral target tissues. After a peak in early adulthood, there is a marked decrease in plasma concentrations throughout adult life. These hormones are thought to affect mood and well-being, have neurosteroid effects and may influence the immune system. Animal experiments suggest that DHEA has many other effects, including anticancer, immune-enhancing, neurotropic and general antiageing effects, but information based on studies in humans is limited. In female patients with adrenal insufficiency, treatment with DHEA replacement doses of 20 to 50 mg results in improvements in mood, quality of life and libido. These studies usually lasted only a few months, so the effect of chronic DHEA treatment or its effectiveness in male patients is not known. Some studies suggest a
favourable effect of pharmacological doses of DHEA in the treatment of depression. DHEA may have a very limited effect on cognitive function in elderly people, and some studies suggest a beneficial immunomodulatory effect of DHEA in patients with autoimmune diseases, but further studies are warranted before introducing DHEA for these indications in clinical practice.