Since Planavila et al. uncovered that FGF-21 can suppress cardiac hypertrophy (Planavila et al., 2013), subsequent studies also demonstrated that FGF-21 exerts protective effects against cardiac ischemic injury (Liu et al., 2013) and inflammation (Yu et al., 2016), and FGF-21 was considered a protective factor in non-metabolic diseases. Here, FGF21 is linked to metabolic disease.