Oxidant stress, in vivo or in vitro, is known to induce oxidative changes in human red blood cells (RBCs). Our objective was to examine the effect of augmenting RBC glutathione (GSH) synthesis on 1) degenerative protein loss and 2) RBC chemokine- and free radical-scavenging functions in the oxidatively stressed human RBCs by using banked RBCs as a model. Packed RBCs were stored up to 84 days at 1-6°C in Adsol or in the experimental additive solution (Adsol fortified with glutamine, glycine, and N-acetyl-L-cysteine). Supplementing the conventional additive with GSH precursor amino acids improved RBC GSH synthesis and maintenance. The rise in RBC -glutamylcysteine ligase activity was directly proportional to the GSH content and inversely proportional to extracellular homocysteine concentration, methemoglobin formation, and losses of the RBC proteins band 3, band 4.1, band 4.2, glyceraldehyde-3-phosphate dehydrogenase, and Duffy antigen (P < 0.01). Reduced loss of Duffy antigen correlated well with a decrease in chemokine RANTES (regulated upon activation, normal T-cell expressed, and secreted) concentration. We conclude that the concomitant loss of GSH and proteins in oxidatively stressed RBCs can compromise RBC scavenging function. Upregulating GSH synthesis can protect RBC scavenging (free radical and chemokine) function. These results have implications not only in a transfusion setting but also in conditions like diabetes and sickle cell anemia, in which RBCs are subjected to chronic/acute oxidant stresses.