ACOX1 and obesity due to melanocortin 4 receptor deficiency: As peroxisomes lack a respiratory chain, electrons from FADH2 are transferred directly to O2, generating H2O2 and heat.45 In line with previous studies,46 obesity appeared to induce peroxisomal FAO, as illustrated by higher expression of peroxisomal‐specific Acyl‐Coenzyme A Oxidase 1 (ACOX1) and Acyl‐CoA Dehydrogenase Very Long Chain (ACADVL).