Human insulin is recombinant protein, which is responsible for the metabolism of carbohydrates and fat in the body. Insulin was first expressed in bacteria. The word insulin is coined from the Latin word "insula" meaning 'island' from the cells that produce insulin. The insulin hormone has the ability to control the blood sugar level by controlling the entry of glucose in the cells of skeletal muscles, liver and fat. Diabetes mellitus is a metabolic disorder, in which a person have high blood sugar due to the insufficiency in insulin production (type 1) or due to resistance to insulin (type 2), both lead to abnormal sugar levels (Diabetes Mellitus).