Glutathione is made from cysteine, glycine and glutamate, using the enzymes gamma-glutamylcysteine synthetase (glutamate+glycine) and glutathione synthetase (adds the glycine).
Cysteine is supposed to be the limiter. Cysteine comes from breaking down homocysteine, which depends on magnesium and B6.
Glutathione uses selenium to detoxify hydrogen peroxide. H2O2 is a common end product of antioxidant action.
Glutathione uses niacin and riboflavin to regenerate itself.