The administration of rhIGF-I in appropriate doses leads to a decrease of insulin and growth hormone secretion and to an increase of insulin sensitivity. In type 2 diabetic patients, IGF-I improves glycemic profiles. In normal subjects, IGF-I increases energy expenditure and lipid oxidation and has a protein-sparing effect. Total and VLDL-triglycerides as well as LDL-cholesterol are decreased by IGF-I administration. This metabolic profile of IGF-I allows speculation on its possible usefulness in conditions of relative insulin resistance often associated with increased cardiovascular morbidity and mortality.