FNDC5 and obesity disorder: Moreover, it has been discovered that irisin is implicated in the advancement of various age-related disorders (Fatouros, 2018; McPhee et al., 2016), such as obesity, diabetes, and sarcopenia—complexities associated with aging (de Freitas et al., 2020; Guo et al., 2023; Marrano et al., 2021).