Some studies have suggested that irisin ameliorates obesity, glucose disorders and insulin resistance14, 30, 31 and that circulating irisin is negatively associated with BMI and percentage of fat mass14, 32; however, other studies have found that irisin is positively correlated with these parameters33, 34 while others have revealed no correlation between irisin and BMI35, 36, 37. Here, FNDC5 is linked to obesity disorder.