Insulin is known for its limited bioavailability when administered orally. One of the advantages of chitosan is its ability to adhere to the mucosal surface when enhanced, which extends the duration of contact and enhances insulin absorption, thereby improving its therapeutic efficacy. This mucoadhesive property of chitosan makes it a valuable component in addressing the challenge of delivering insulin orally. Moreover, chitosan acts as a permeation enhancer without causing significant damage to the mucosal membrane. Chitosan has shown its effectiveness in various oral insulin formulations, including liquid mixtures, nanoparticles, and microparticles. Additionally, various derivatives of chitosan are employed as mucoadhesive and encapsulating polymers, stabilizers, and permeation enhancers in these formulations, with the long-term goal of replacing the need for insulin injections. Another study by Seyam, Salma et al. focused on the application of insulin-loaded chitosan and chitosan derivative nanoparticles. The successful encapsulation of insulin, along with the ability to modulate size, surface charge, and release profiles, presented chitosan as a promising candidate for oral insulin delivery. Compared to conventional oral insulin administration, chitosan-based nanocarriers have shown marked improvements in bioavailability and blood glucose-lowering effects. This is primarily due to chitosan's mucoadhesive properties, which prolong the residence time of the nanoparticles near absorption sites in the intestines, facilitating insulin transport through either transcellular or intracellular pathways to the bloodstream, eventually reaching the liver via the portal vein. Chitosan derivatives are also employed to enhance solubility and broaden its application as a drug delivery system while retaining its beneficial characteristics. Moreover, modifying chitosan can provide control over cargo release throughout the gastrointestinal tract and regulate the surface charge of the nanoparticles, further enhancing protection and promoting insulin absorption and bioavailability. Additionally, chitosan or its derivatives can serve as a coating for nanoformulations, adding versatility in achieving specific therapeutic goals.