CLOCK single nucleotide polymorphisms (SNPs) are associated with obesity, hyperglycemia and type 2 diabetes-associated cardiovascular diseases, Alzheimer’s disease and the quality of aging in a cohort of nonagenarians.17–21 Moreover, CLOCK deficiency leads to reduced lifespan and the occurrence of aging-associated pathologies, including cataracts and dermatitis, in mice.22 However, the molecular mechanisms and targets by which CLOCK regulates organismal aging remain largely unexplored. Here, CLOCK is linked to obesity due to melanocortin 4 receptor deficiency.