Selective, non-transportable inhibitor of GlyT1 which displays no activity at GABA or glutamate receptors (IC50 values are 2.8, 9.8 and 56000 nM for hGlyT1, rGlyT1 and rGlyT2 respectively). Enhances the amplitude of the NMDA component of glutamatergic EPSCs. R-enantiomer also available.. Purity 98%. MW (observed): 393.45