Q2: What is the shelf life
Even when a small fraction does reach the viable epidermis, the molecule has a short functional half-life unless it is stabilized in the formulation (encapsulation, copper chelation, or both) 1
Also, the level of reduction in glutathione has been associated with Parkinsons disease severity (less glutathione, more advanced PD)
Poo MM, Pignatelli M, Ryan TJ, Tonegawa S, Bonhoeffer T, Martin KC, Rudenko A, Tsai LH, Tsien RW, Fishell G, Mullins C, Gonalves JT, Shtrahman M, Johnston ST, Gage FH, Dan Y, Long J, Buzski G, Stevens C (2016) What is memory
Controlling the bioactivity of a peptide hormone in vivo by reversible self-assembly
Second, many patients on calorie-restricted diets already have suboptimal B12 levels