The preservative inhibits the growth of bacteria, which is what allows a sealed multi-dose vial to be entered with a sterile needle repeatedly typically over a 28-day in-use window without the remaining contents losing sterility
Tang L, Wang W, Zhou W, Cheng K, Yang Y, Liu M, Cheng K, Wang W (2015) Three-pathway combination for glutathione biosynthesis in Saccharomyces cerevisiae
They should be kept at room temperature, away from moisture, heat, and especially light, as light can make the vitamin unstable
Reduced glutathione in amyotrophic lateral sclerosis: an open, crossover, randomized trial
[6] Veganspeople who choose to not consume any animal-sourced foodsare at risk because plant-sourced foods do not contain the vitamin in sufficient amounts to prevent vitamin deficiency