(1R)-1,5,-Dihydroxyempagliflozin-d4 is labelled (1R)-1,5,-Dihydroxyempagliflozin (D452715), an impurity of Empagliflozin (E521510) which is a novel, potent and selective SGLT-2 inhibitor, improves glycaemic control and features of metabolic syndrome in diabetic rats.