Insulin is the cornerstone of type 1 diabetes therapy and a critical addition for type 2 diabetes control. Despite significant advancements in insulin therapy research, including the creation of innovative insulin formulations and delivery systems, there are still numerous difficulties and unknowns surrounding insulin therapy. The main issues with more recent pharmacological and technological methods are biocompatibility, degradation/clearance of delivery materials, immunogenicity, stability, the precision of dosing, reproducibility of an effect similar to that of endogenous insulin, predictability of performance, and safety over time. In order to achieve a protracted, flatter profile, with fewer instances of hypoglycemia and an improvement in postprandial glucose level, more recent insulin mutants were developed. The "meal" (glucose-responsive) insulins, which are supplied in accordance with an endogenous glucose-sensing feedback mechanism, best represent the future generation of insulin treatment. Insulin delivery methods with novel jet injectors, smart pens, patch pumps, and other needle-free tools for subcutaneous doses are another area of ongoing advancements. Digital health has significantly advanced treatments in recent years. As such, insulin treatments should become more scalable and potentially more cost-effective.