There is inorganically bound selenium (e.g. sodium selenite) and organically bound selenium (e.g. selenomethionin, selenocysteine).
Today it is known that inorganic selenium (sodium selenite) is particularly beneficial. It is quickly and well available for the body and is incorporated specifically into the specific protective systems.
How can the good availability of sodium selenite be explained?
From the chemical point of view, sodium selenite has to be modified only marginally and can be incorporated by our organism quickly and specifically into the specific selenium-containing enzymes.
In contrast, the absorption process is more laborious with organic selenium. At first, it is treated like a normal protein component by the body and incorporated unspecifically into e.g. the muscles. There, the selenium is not acutely available for the organism at first but has to be transferred into pre-stages only when required before being incorporated into the specific selenoenzymes.