Currently, 2-3% of the population of the United Kingdom and United States of America receive glucocorticoid therapy. Significant adverse effects are not confined to chronic use; recurrent short-course administration is associated with increased morbidity and mortality. The adverse metabolic features associated with glucocorticoid use include obesity, skeletal muscle myopathy, hypertension, insulin resistance and diabetes and are collectively termed 'iatrogenic Cushing's syndrome'. The efficacy of glucocorticoid therapy is not in doubt, but there are no interventions to reduce their metabolic consequences. Within metabolic tissues (liver, skeletal muscle, adipose), 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) regenerates active glucocorticoid and therefore is able to tightly control the availability of glucocorticoids to activate the glucocorticoid receptor. In preclinical studies, the investigators have shown that 11β-HSD1 is critical in regulating the development of the adverse features associated with circulating glucocorticoid excess, endorsing our observations in a patient with Cushing's disease, who was protected from a classical phenotype due to a functional deficit in 11β-HSD1.