INS and obesity due to melanocortin 4 receptor deficiency: The mice fed an HFD and treated with metformin showed low fasting glycemia values, improvements in their glucose tolerance, and increased insulin sensitivity when treated with a dose of 50 mg/kg of the drug, a lower dose than those used in studies with the same in vivo model system of obesity but without the use of a nanostructured lipid system [28,29].