The doses were a bit high:
1.33 mmol/kg/d of glycine = 100mg/kg per day
0.81 mmol/kg/d of cysteine (as N-acetylcysteine) = 100mg/kg per day
a 70kg person (154lb) would have to take 7g Glycine and 7g NAC per day.
Effect of Increasing Glutathione With Cysteine and Glycine Supplementation on...
Objective: To assess whether tadalafil improves endothelial dysfunction(EnD) in a placebo-controlled randomized-control trial.
Methods: Erectile dysfunction and EnD were assessed by the International Index of Erectile Function (IIEF-5) and flow-mediated dilation (FMD) of the brachial artery...