Myths vs facts: MC4R and fatigue

MC4R (melanocortin-4 receptor) is a key regulator of energy balance and appetite. Variants (e.g., rs17782313) are associated with higher BMI and obesity risk. However, a direct causal link between MC4R variants and fatigue is not scientifically established. Fatigue may arise secondarily from obesity-related conditions such as sleep apnea or metabolic syndrome, which can be influenced by MC4R polymorphisms. Effect sizes of individual SNPs are small and not clinically predictive. Consumer DNA tests claiming a direct 'fatigue predisposition' via MC4R overstate the evidence. Without confirmation from replicated studies or medical evaluation, no dietary or lifestyle change should be based solely on an MC4R SNP. Evidence: unclear – mechanistic and GWAS hints exist, but no robust clinical connection to fatigue. Sources: none in provided context.