Laboratory evolution of glutathione biosynthesis reveals natural compensatory pathways Nature Chemical Biology Every time you exercise your body generates oxidative stress as a natural byproduct of muscle contraction and energy production. At moderate levels that is a healthy signal. But when exercise intensity exceeds Appraising the Role of Astrocytes as Suppliers of Neuronal Glutathione Precursors NAC (N Acetyl L Cysteine) Glutathione Precursor Molecular Provisions Glutathione and the Cofactors