Although lorcaserin inhibits GSIS by activating 5-HT2CR in the islets, lorcaserin improves glucose tolerance, ameliorates hyperinsulinism, reduces hepatic glucose production, increases glucose disposal and then improves high blood glucose through activating 5-HT2CR in the hypothalamus, which does not need islets to compensate to secrete more insulin to lowing blood glucose(Thomsen et al., 2008; Xu et al., 2008; Higgins et al., 2015; Apovian et al., 2016; Pi-Sunyer et al., 2016; Burke et al., 2017). Here, INS is linked to hyperinsulinism.