Cytidine-d13 (Cytosine beta-D-riboside-d13) is deuterium labeled Cytidine (HY-B0158). Cytidine is a pyrimidine nucleoside and acts as a component of RNA. Cytidine is a precursor of uridine. Cytidine controls neuronal-glial glutamate cycling, affecting cerebral phospholipid metabolism, catecholamine synthesis, and mitochondrial function[1][2][3].