There is no exact number for how much insulin should be given at one time, it is different for each patient and depends on the type of insulin, the patient’s weight, and blood glucose. Insulin includes short-acting insulin, intermediate-acting insulin and long-acting insulin, and the appropriate insulin should be chosen according to the blood sugar condition. And the heavier the weight and the higher the blood sugar, the higher the dose of insulin needed each time. However, there are differences in the sensitivity of different individuals to insulin. For patients taking insulin for the first time, it is recommended that the insulin should be started at a small dose, and then according to the level of blood glucose control to decide whether to increase or decrease the dose, and it usually requires several adjustments to formulate an appropriate insulin treatment program. The common adverse reactions to insulin are hypoglycemic reaction, there will also be allergic reaction, edema, weight gain, refractive error, as well as redness, swelling and warmth of the skin at the site of injection, and prolonged injection at the same site may lead to lipoatrophy. Insulin should be used strictly under medical supervision.