MC4R and obesity due to melanocortin 4 receptor deficiency: One of the first hypothesis had been that INSTIs and, in particular, dolutegravir, could exert an inhibitory effect on α-melanocyte-stimulating hormone (α-MSH), an anorexigenic neuropeptide, by binding of melanocortin 4 receptor, which may interfere with the regulation of food intake and lead to obesity [75].