The present disclosure relates to a pro-drug peptide, or a salt thereof, having improvement for at least one biological property relative to a parent peptide or peptidomimetic, wherein the biological property is selected from the group consisting of therapeutic index, stability, solubility, toxicity, adsorption, and pre-systemic metabolism. The pro-drug peptide comprising the following structure: Z-pep, wherein: pep is the parent peptide or peptidomimetic; Z is a sequence of n amino acids, Z is cleaved in vivo releasing pep; n≥2 amino acids. The present disclosure also relates to methods of making and using the pro-drug peptide of the present disclosure. For example, the present disclosure describes a pro-drug peptide that may be used to prevent, treat, or ameliorate at least one symptom of hypoglycemia or a hypoglycemia-related disease or disorder.