A method of treating a condition or conditions caused by damage to cells by a process of oxidative stress and glutathione depletion. In some exemplary embodiments, the condition or conditions may be treated by administering reduced L-glutathione to a patient through injection or intravenous infusion. In other exemplary embodiments, the condition or conditions may be treated by administering reduced glutathione monoethyl ester through injection or intravenous infusion.
