Oral glutathione is poorly absorbed because it is broken down during digestion
Acknowledgements This work was supported by grant BK20140049 from the Jiangsu Province Funds for Distinguished Young Scientists, BK20161082 from the Natural Science Foundation of Jiangsu Province and from the National Natural Science Foundation of China(NOs 81274150, 81403092, 81573964)
doi: 10.1016/j.scienta.2019.02.026 115 ZhouY.DiaoM.CuiJ.-X.ChenX.-J.WenZ.-L.ZhangJ.-W.et al
Alertness, focus perceiving and mood perceiving were measured insignificantly in one study (19)
If you are going with oral or sublingual glutathione, most people start from about 250 mg to 500 mg per day
Bremelanotide, PT-141, has since been explored as a treatment for men with decreased libido and ED