BAY-876 is a potent, highly selective, cell-permeable inhibitor of glucose transporter GLUT1. It had an IC50 value of 2 nM in vitro and inhibited glucose uptake by Hela-MaTu cells with an IC50 value of 3.2 nM. BAY-876 was at least 130-fold selective for GLUT1 relative to GLUT2, GLUT3, GLUT4 and a panel of 18 kinases and 68 proteins.BAY-588 is used as a negative control and is available from Sigma.