Since its discovery and production in 1921, insulin has saved millions of diabetic patients, for which the inventor of insulin, the great medical scientist Banting and his colleagues were awarded the Nobel Prize. Nowadays, insulin is widely used in the clinical treatment of diabetes, not only in the treatment of type 1 diabetes, diabetic pregnancy or gestational diabetes, but also in the treatment of many patients with type 2 diabetes. There are various types of insulins, which can be divided into animal insulins (bovine insulin, porcine insulin), human insulins and insulin analogues according to their sources. Animal insulin is extracted from bovine or porcine pancreas, and its molecular structure is not exactly the same as that of human insulin, which is prone to allergy or insulin resistance, but it is cheap and can be easily afforded by patients, and most of the animal insulins used in China are porcine insulins. Human insulin is produced by genetic engineering, with high purity and less side effects, but it is more expensive. The commonly used ones are Novolin produced by Novo Nordisk of Denmark, Utrolin produced by Eli Lilly of the United States and Ganshulin of China. Insulin analogues include fast-acting insulin analogues and long-acting insulin analogues, which are the only fast-acting preparations used in China. Insulin can be divided into ultra-short-acting insulin, short-acting insulin, medium-acting insulin and long-acting insulin according to the duration of action. 1, ultra-short-acting insulin is a human insulin analogue, which is produced by recombinant technology in recent years, with an onset of action of 15 minutes, a peak action of 30-45 minutes and a duration of about 2-4 hours, currently used in Novalis (Aspart) and Unilog (Lispro). Short-acting insulin is the most commonly used common insulin, a colorless and transparent liquid, the onset of action is 20-30 minutes after subcutaneous injection, the peak effect is 2-4 hours, and the duration is 6-8 hours, the animal insulins are common insulin or neutral insulin injection produced in Shanghai and Xuzhou, and the human insulins are Novolin R and Eugenol R, etc. Short-acting and ultra-short-acting insulins need to be injected subcutaneously before three meals and are mainly used to control postprandial blood glucose; short-acting insulins can be administered intravenously; in addition, short-acting and ultra-short-acting insulins can be administered subcutaneously continuously by insulin pumps to treat type 1 diabetes mellitus whose blood glucose is difficult to control. Because of the slow onset and long duration of action of short-acting insulin subcutaneously, the risk of early postprandial hyperglycemia and hypoglycemia before the next meal is increased, and the compliance of insulin injection 30 minutes before meal is poor. Ultra-short-acting insulin has the characteristics of fast onset, fast peak and short duration of action, which is more in line with physiological needs, better reduces postprandial blood glucose peak, less hypoglycemia, and more convenient for treatment, especially for elderly people or diabetic nephropathy patients who are prone to hypoglycemia. 2, medium-acting insulin, also known as low arginine zinc insulin, is a milky white turbid liquid, with an onset of action of 1.5 to 4 hours, a peak of action of 4 to 12 hours, and a duration of about 14 to 20 hours. It is generally used to control nighttime and fasting blood glucose, and can be injected subcutaneously in the early morning and at bedtime, and can be used in combination with oral hypoglycemic drugs and short-acting insulin. Long-acting insulin, also known as arginine zinc insulin, is a milky white cloudy liquid with an onset of action of 3 to 4 hours, a peak effect of 14 to 20 hours and a duration of about 24 to 36 hours. Long-acting insulin only needs to be injected once a day due to its long duration of action, and is often injected subcutaneously in the early morning, and often needs to be combined with short-acting insulin. 4, in addition, in order to meet further needs, imported insulin and the short-acting preparations and medium-acting preparations (R and N) are mixed in different proportions to produce premixed insulin with an action time between the two. For example, Novolin 30R, Novolin 50R, and Eugenol 70/30. 30R means mixing 30% of short-acting R with 70% of intermediate-acting N insulin; 50R means 50% of short-acting R and 50% of intermediate-acting N each. All of the above drugs have an onset time of 30 minutes, a peak time of 2 to 8 hours and a duration of 24 hours. The insulin premix formulation requires only two subcutaneous injections per day (before breakfast and dinner), which is particularly convenient for some patients who have difficulties in extracting insulin, and it is mostly used by type 2 diabetic patients whose pancreatic islets are still functional. The disadvantage is that the dose of short-acting or intermediate-acting insulin cannot be adjusted at will. At present, the number of people using insulin in China only accounts for 10%-20% of diabetic patients, which is much lower than that of developed Western countries, which is related to the misunderstanding of Chinese people about insulin. For a long time, diabetic patients often have such concerns in their minds: once insulin is used, type 2 diabetes will also become insulin-dependent diabetes, from which they can no longer leave insulin; some even compare insulin with opium. In fact, these are big mistakes, because insulin is a hormone in the human body, so as long as the correct use, insulin is not any harm to the human body. Dependence on insulin is only related to the condition, and has nothing to do with the early or late use of insulin. The only disadvantage of insulin use is that it must be given by subcutaneous injection, thus causing inconvenience and pain to the patient, in addition to being prone to hypoglycemia if used improperly. Even so, insulin therapy has superiority that cannot be compared with oral hypoglycemic drugs: the strongest ability to control blood sugar, the least toxic side effects, and low medical expenses.