Purity >98%. Calcium-sensing receptor (CaSR) is a G protein-coupled receptor that is involved in calcium homeostasis. Calhex 231 is a negative allosteric modulator of CaSR that blocks calcium-mediated activation (IC50 = 0.39 μM). It also attenuates the activation of CaSR by calcimimetics, like calindol and R-568. Calhex 231 is commonly used to study the role of CaSR in various cell types, including stem cells.