Is MC4R useful for fatigue?

The provided context contains no data or studies linking the MC4R gene to fatigue. MC4R is primarily known for its role in energy homeostasis, appetite regulation, and body weight. Rare MC4R variants are associated with obesity, but not with general tiredness or chronic fatigue syndromes. Consumer DNA tests often overclaim single-gene effects. Without specific evidence from clinical trials or GWAS, the claim that MC4R is useful for fatigue is speculative and likely marketing-driven. Fatigue is multifactorial (sleep, stress, nutrition, thyroid, mental health) and cannot be assessed by a single SNP. Evidence: unclear. Sources: none in context.