Peptide therapeutics offer unique advantages in treating a variety of diseases, including cancer and metabolic disorders, due to their high specificity and potency. However, these molecules face significant stability challenges, including susceptibility to enzymatic degradation, physical instability, and chemical degradation. This review explores innovative strategies to enhance the stability of peptide therapeutics, focusing on advanced analytical methods such as mass spectrometry, high-performance liquid chromatography, circular dichroism spectroscopy, and differential scanning calorimetry. Additionally, the review discusses the role of pharmaceutical formulations and novel drug delivery systems (NDDS) in improving the efficacy and stability of peptide drugs, highlighting recent advancements in green formulations and lipid-based delivery systems.