Peroxiredoxin 6, an antioxidant enzyme, prevents SIRT1 cleavage, as well as forkhead box O1 (FoxO1) expression, and when absent leads to muscle degeneration associated with sarcopenia.187 Increased FoxO expression increases proteolysis, leads to increased senescence, and accelerates age- and obesity-induced muscle degeneration.188 The role of perimuscular adipose tissue accumulation around muscle has also been explored in the development or sarcopenia. Here, FOXO1 is linked to obesity due to melanocortin 4 receptor deficiency.