Prodrug formulations of insulin and insulin analogs are provided wherein the insulin peptide has been modified by an amide bond linkage of a dipeptide prodrug element. The prodrugs disclosed herein have extended half lives of at least 10 hours, and more typically greater than 2 hours, 20 hours and less than 70 hours, and are converted to the active form at physiological conditions through a non-enzymatic reaction driven by chemical instability.