Only after the liver, lungs, and immune system have what they need is the "excess" glutathione available to influence skin pigment pathways
N Engl J Med (2008) 359(15):157789
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Additionally, stress, infection, leaky gut, inflammation, medications, smoking, and excessive alcohol consumption can further decrease this absorption
Furthermore, a comprehensive review published in the Journal of Translational Medicine proposed a unifying model for ME/CFS and Long COVID, highlighting how viral infections (like SARS-CoV-2 or Epstein-Barr Virus) trigger a cascade of immune exhaustion, micro-clotting, and severe oxidative stress