Blood glucose around 16mmol/L can not determine whether you need to take insulin, not to mention how much insulin to take. You should go to the hospital to complete the relevant examinations and then determine the glucose-lowering program according to your individual situation. Blood glucose around 16mmol/L generally suggests diabetes, diabetic patients should be based on their body weight, pancreatic β-cell function, sensitivity to insulin, with or without the combination of acute and chronic complications, etc. to formulate a treatment plan, and the dosage of each patient is different. The common adverse reaction to insulin injection is 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 injection site, and prolonged injection in the same area may lead to fat atrophy. Insulin should be applied under medical supervision.