Studies by Sharan et al. [1], Telagareddy et al. [17], Zhang et al. [18], and Adamska et al. [8] found increased serum irisin levels, similar to the present study, whereas other research by Wang et al. [19], Abali et al. [20], and Foda et al. [3] reported either reduced or comparable irisin levels between PCOS patients and controls. This evidence concerns the gene FNDC5 and polycystic ovary syndrome.