concentration of glutathione in plama Oral Administration S-acetyl-glutathione: Impact on the Levels of Plasma and in Erythrocytes of Healthy Volunteers : Figure 2 Status of glutathione in low-molecular-weight
Description
ODonnell KA, Boeke JD

It is not telling you to avoid it either

A study from two randomized trials with healthy male subjects ( n = 15) showed that coffee intake could acutely improve human vascular function, likely through 5-CQA and its physiological metabolites [111]

It's like, oh, well, should it be getting into your brain

Life Sci 218:165184
