Cysteine is often the "bottleneck" in glutathione production
Potentially, you could add the push towards more plant-based diets, increases in phytic acid, and lower vitamin C intake plus modern stressors impacting digestion such as stomach acid production, all hindering iron absorption
[DOI] [Google Scholar] 28.Kang Y., Choi H., Na J., et al
& Sakai, T
Brighten Your Skin Naturally Fight Aging with Antioxidants Boost Your Overall Wellness Quick, Effective Rejuvenation What Areas Are Treated with Glutathione IV Push
Low SAM, excessive methylation demand, impaired creatine synthesis, reduced glutathione availability and oxidative stress may place additional strain on mitochondria, potentially contributing to fatigue, variable cognitive stamina, sensory sensitivity, poor stress tolerance and slow recovery from illness