High insulin and C-peptide suggests that there may be insulin resistance in the body, not necessarily diabetes, and requires monitoring of fasting and 2-hour postprandial blood glucose. Insulin is a hormone produced by pancreatic islet B cells that can lower blood glucose, serum insulin is regulated by blood glucose concentration, and when blood glucose rises, it can stimulate insulin to rise. c-peptide is also secreted by pancreatic islet B cells, and c-peptide is not easy to be degraded by the liver, so c-peptide value can reflect the insulin content and islet cell function well. If insulin and C-peptide are elevated at the same time, it means that there is insulin resistance in the patient’s body, not necessarily diabetes. The diagnosis of diabetes mellitus should be based on the combination of fasting blood glucose, 2-hour postprandial blood glucose concentration, and the presence or absence of clinical signs of diabetes mellitus such as polydipsia, polyphagia, polyuria, and so on. If you have high insulin and C-peptide levels, it is recommended that you go to the hospital and ask your doctor to make a judgment, rather than making a blind judgment on your own.