INS and type 2 diabetes mellitus: In a recent clinical trial testing the effect of oral glutathione (GSH) supplementation for 3 weeks in obese subjects with and without T2D, the whole-body insulin sensitivity and skeletal muscle GSH significantly increased in the GSH group; oddly however, no changes were seen in skeletal muscle mitochondrial H2O2 emission rate, a measure of oxidative stress, pre- and post-GSH supplementation [131].