Selenium is an important antioxidant for your body and is required as a cofactor of glutathione peroxidase. At the same time, it is incorporated into proteins to make selenoproteins, the antioxidant properties of which contribute to blocking cellular damage from free radicals. High doses of vitamin C (over 1 gram) may enhance the absorption of selenium. This mineral is best taken in conjunction with antioxidant supplements, such as vitamins C or E.

Se-Methyl L-Selenocysteine is a naturally occurring seleno-amino acid that is synthesised by plants, such as garlic and broccoli. It is an organoselenium compound and also more bioabsorbable than other forms. Unlike selenomethionine, which is incorporated into proteins in place of methionine, this amino-acid is not absorbed into any proteins. Thus, it is fully available for the synthesis of selenium-containing enzymes, such as glutathione peroxidase.