Calhex 231 hydrochloride is a CaSR inhibitor via negative allosteric modulation. Calhex 231 hydrochloride blocks Ca 2+-induced accumulation of [3H]inositol phosphate with an IC50 of 0.39 μM in HEK293 cells. Calhex 231 hydrochloride has the potential for diabetic cardiomyopathy (DCM) treatment.