Elemental Selenium and Vitamin B2 (riboflavin) are essential for glutathione use and recycling. Selenium is really low in Australian soils, and people are commonly deficient. Signs of low B2 are blood Riboflavin for women's health and emerging microbiome strategies npj Biofilms and Microbiomes Effect of riboflavin supplementation on erythrocyte glutathione stability Table 3 from Riboflavin requirements of Filipino children and non pregnant, pregnant and lactating women: Studied by the erthrocyte glutathione reductase activation test. Semantic Scholar