The present invention relates to compositions comprising thyroxine (T4) and triiodothyronine (T3). More specifically, the invention relates to thyroxine (T4) and triiodothyronine (T3) compositions that include a peptide carrier and thyroxine (T4) and triiodothyronine (T3) covalently attached to at least one of the N-terminus, the C-terminus, a side chain of the peptide carrier, and/or interspersed within the peptide chain; methods for protecting and administering thyroxine (T4) and triiodothyronine (T3); and methods for treating thyroid disorders.