D-Serine-d3 ((R)-Serine-d3) is a deuterium labeled D-Serine (HY-100808). D-Serine ((R)-Serine), an endogenous amino acid involved in glia-synapse interactions that has unique neurotransmitter characteristics, is a potent co-agonist at the NMDA glutamate receptor. D-Serinee has a cardinal modulatory role in major NMDAR-dependent processes including NMDAR-mediated neurotransmission, neurotoxicity, synaptic plasticity, and cell migration[1][2][3].