oral glutathione dosage Effectiveness of of spinach-derived and How to Take Glutathione Effectively:

PMID 25221399

In general, the rate of synthesis, regeneration, and recycling of glutathione is determined by three key factors 2 : Cellular levels of cysteineCysteine availability is the rate-limiting step in glutathione production, so not enough cysteine and de novo synthesis of glutathione will slow Enzyme glutamate cysteine ligase (GCL) activity, in part regulated by glutathione feedback inhibition Glutathione depletion due to high levels of oxidative stress, inflammation, or exposure to xenobioticsin these situations, de novo synthesis is upregulated Of course, as an antioxidant, one of the most important roles of glutathione is shielding cells from reactive oxygen species and reactive nitrogen species, but thats not its only job

Glutathione deficiency raises oxidative stress levels, which may cause cancer, according to an article referenced in the Journal of Cancer Science and Therapy

Here is the complete step-by-step lab protocol