The blood sugar level that requires insulin varies depending on the individual and their specific situation. However, according to the American Association of Clinical Endocrinologists, insulin therapy should be started if a person with type 2 diabetes has an A1C level above 9% . Additionally, insulin therapy will often need to be started if the initial fasting plasma glucose is greater than 250 or the HbA1c is greater than 10% . It is important to note that insulin therapy should be started and adjusted to achieve a reasonable goal HbA1c for the patient. The goal HbA1c level may vary depending on the patients age, overall health, and other factors. Therefore, it is best to consult with a healthcare professional to determine the appropriate blood sugar level that requires insulin for an individual.