sarcosine + D-serine

Sarcosine + D-serine is a combination of two naturally occurring amino acid derivatives, both of which modulate the N-methyl-D-aspartate (NMDA) receptor in the central nervous system. Sarcosine acts as a glycine transporter 1 (GlyT-1) inhibitor, increasing synaptic glycine levels and thereby enhancing NMDA receptor function. D-serine is a full agonist at the glycine modulatory site of the NMDA receptor, directly facilitating its activation. Both agents have been investigated as adjunctive treatments for schizophrenia, particularly for negative and cognitive symptoms that are inadequately addressed by standard antipsychotic therapy. Clinical studies suggest that while both compounds can improve symptoms in chronic schizophrenia when added to antipsychotics, sarcosine may be more effective than D-serine in acute exacerbations[1][3][4][5]. The combination has also shown synergistic effects on NMDA receptor modulation in preclinical models[2].