Although its elevated levels may be perceived as a compensatory response in certain contexts, gain-of-function experiments and other evidence posit that Musclin primarily acts as a “pathological driver,” demonstrating context-dependent effects in obesity, type 2 diabetes mellitus (T2DM), hypertension, and other components of metabolic syndrome (MetS). This evidence concerns the gene OSTN and obesity due to melanocortin 4 receptor deficiency.