Exposure to HIV medications has been associated with metabolic changes including generalized fat depletion (lipoatrophy), high triglyceride levels, and in some patients, high sugar levels or diabetes. This syndrome is associated with a deficiency of leptin, a hormone produced by fat cells. Recent studies involving leptin administration to patients with congenital lipoatrophy have shown dramatic improvements in metabolic parameters such as insulin resistance and hyperlipidemia. Leptin administration to patients with HAART-induced lipoatrophy may also lead to significant improvements in the metabolic abnormalities found in these HIV+ patients. The aims of this study are to examine the effect of leptin administration on insulin resistance and other parameters of the metabolic syndrome in HIV patients with HAART-induced lipoatrophy.