As a clinical corollary, human studies in stressed adults with acute respiratory distress syndrome have demonstrated elevated concentrations of glutathione and improvements in recovery after cysteine supplementation. Septic and malnourished children supplemented with enteral cysteine have demonstrated increased glutathione concentrations and in vivo glutathione synthetic rates measured utilizing a novel non-radioactive, stable isotope methodology. Furthermore, the septic children supplemented with cysteine resolved their illnesses quicker than their unsupplemented counterparts. These studies suggest that cysteine-HCl supplementation may improve glutathione production and decrease oxidative stress in critically ill neonates.