This is because the conversion requires a lot of
different pieces to be in place, including having enough nutrients (that act as
cofactors in the chemical process), having proper gut and liver function, and the body needs to be on a low - stress setting, as chemical messengers related to stress may block or alter the conversion, resulting in the person not having enough of the T3 on board.
These vitamins are essential for a long list of physiological processes and biochemical reactions in the body; they serve as
cofactors for enzymes and as carriers for electron transport between
different processes involved in human metabolism and growth.