Abstract: Polypeptides that fold into biologies are stabilized by diselenide bonds between selenocysteine amino acids. Methods to produce such polypeptides in genomically recoded organisms (GRO) can be scaled up for industrial production. Since diselenides have the same geometric bond angles and torsions as disulfides, as well as very similar bond lengths, they can be substituted into polypeptides without disrupting the three dimensional structure of the polypeptides. Diselenides render the polypeptides resistant to reduction when they are exposed to blood serum or to reducing components of blood serum or to reducing components components within cells.