The bioavailability of orally supplied glutathione (γ-Glutamylcysteinylglycine) could be proved.
Bioavailability Glutathione
The acetylating of vital nutrients may be a method to improve the bioavailability and stability of the substance.

I am critical about the administration of S-acetyl-glutathione or S-acetyl-L-glutathione because as far as I know there are no studies available which have examined the effects of this substance closely. A large number of studies exist about the proven efficacy of reduced glutahtione GSH. The acetylation may indeed increase the bioavailability, but also changes the molecule.
In any case, an influence of the body’s glutathione production (downregulation) due to oral administration of glutathione is not to be expected, since the production of glutathione depends on the presence of sulfur-containing amino acids and not on the glutathione level.