Associative interactions between folic acid and proteins are well known. This work leverages these interactions to engineer folic acid nanoparticles for controlled release of insulin during diabetes therapy. The insulin-loaded folic acid nanoformulation is synthesized during this study and more than 70% protein loading with less than 10% insulin loss have been maintained during the synthesis process. The folic acid nanoparticles of 50–150 nm size are further characterized in the present study. The loading efficiency of these particles is significantly better compare to previous strategies. The release behaviour of insulin from nanoparticles has been studied to quantity released insulin and folic acid with time using high performance liquid chromatography. Insulin release results suggest that more than 90% of the insulin is encapsulated and released within 24 h from folic acid nanoparticles. The analysis of folic acid release along with insulin indicates that the particles are formed by folic acid-insulin complexation at the molecular level. The release of insulin from nanoparticles is controllable with the change in the crosslinking salt concentration as well as the amount of folic acid loaded during particle synthesis. These results prove that folic acid nanocarriers are capable to control the release of insulin.