does nac convert to glutathione biosynthetic scheme. N-acetyl-L-cysteine (NAC) can supply Effects of N-acetylcysteine, oral glutathione

NG2-glia decrease the brain endothelial permeability and this improvement of BBB function is inhibited by a platelet-derived growth factor receptor inhibitor, which cannot influence the oligodendrocyte-induced BBB integrity [98]

Some animal research have even suggested that glutathione may strengthen the gut barrier by reducing intestinal cell death

So injecting beyond a certain point may cause your cells to fight off the excess B12 so hard that it might reduce the amount of active cellular B12 - probably not to dangerous levels, but possibly sufficient to trigger some symptoms

The underground biohacking community spent years generating the real-world data that clinical trials are supposed to produce