Besides the application of a MCHR1-PET tracer for compound dose selection of potential MCHR1-targeting drugs, another potential implication for obesity patients could be the in vivo quantification of the MCHR1—which is predominantly expressed in the lateral hypothalamus [8]—as a risk factor and early diagnostic tool for insulin resistance. Here, MCHR1 is linked to obesity due to melanocortin 4 receptor deficiency.