When ceramide biosynthesisis upregulated, these molecules tend to accumulate in tissues, contributingto metabolic dysfunction. Recent researchhas revealed that, in obesity accompanied by insulin resistance, accumulatedceramides impair insulin signaling by inhibiting hormone-sensitivelipase, leading to increased circulating free fatty acids, a hallmarkof obesity., This evidence concerns the gene INS and obesity due to melanocortin 4 receptor deficiency.