Under basal conditions, the expression of FGF21 is predominantly from liver and adipose tissue (Nishimura et al., 2000), however, the expression and secretion of FGF21 from skeletal muscle is significantly increased under certain conditions, such as mitochondrial dysfunction (Keipert et al., 2014; Lehtonen et al., 2016; Steele et al., 2016; Khan et al., 2017; Romanello et al., 2019), muscular dystrophy (Lovadi et al., 2017; Zhou et al., 2018; Li et al., 2020), and exercise (Ost et al., 2016; Kruse et al., 2017; Morville et al., 2018). Here, FGF21 is linked to muscular dystrophy.