reduced glutathione reviews Complex Reduced Glutathione VS L Glutathione:

Fluid may leak from the accumulated blood in the veins into the surrounding tissue which can cause skin irritation, reddening and itching

There are several nutrients of note necessary to produce glutathione and for which studies have found that increasing the amount relates to a boost in glutathione levels

Superoxide anions may directly react with NO, thereby stimulating the production of the NO/superoxide anion reaction product peroxynitrite (ONOO ), which in turn has been shown to uncouple the endothelial nitric oxide synthase (eNOS), thereby causing an anti-atherosclerotic NO-producing enzyme to become a ROS-producing enzyme, thus accelerating the atherosclerotic process

doi:10.1038/clpt.2010.57

Long-term use should be approached cautiously because some patients report mild side effects like nausea or injection site discomfort, and research on prolonged use is limited. To minimize the risk of adverse reactions, always get the injections from a registered physician