One u means one unit, and one unit of insulin is equivalent to how many ml, depending on which kind of insulin is used. There are mainly two types of clinical insulin, one is the old type insulin and the other is the refill type insulin, the packaging and dosage of which are different. 1. old type insulin: the insulin that needs to be extracted with a syringe, the specification is 10ml a bottle, containing 400 units of insulin, which is equivalent to 0.25ml of insulin per unit. The insulin is of the refill type, so you can clearly see how many units of insulin have been injected by rotating the screw, which is both accurate and convenient. Patients are recommended to use pencil insulin, which is easy to operate, simple to use, and less prone to errors and better treatment results. Generally, type 1 diabetic patients need to use insulin for life. type 2 diabetic patients can use oral medication as well as insulin, and can also combine oral medication with insulin. The specific use of medication is related to the patient’s condition, and it is recommended to follow medical advice for treatment.