High fasting insulin and C-peptide suggests that the body may have insulin resistance, which simply means that the body’s sensitivity to insulin decreases, in order to control blood glucose and thus secrete more insulin, which is commonly found in pre-diabetes, patients with type 2 diabetes mellitus and obese people. High fasting insulin: High fasting insulin level may have insulin resistance, common in pre-diabetes, type 2 diabetes and obese people. Insulin promotes the uptake of glucose by skeletal muscle, cardiac muscle and adipocytes. It also inhibits the breakdown of glycogen by the liver, inhibits glucose xenobiosis and reduces glucose output. High fasting C-peptide: C-peptide is a reflection of the function of the body’s pancreatic islet cells to secrete insulin, high C-peptide is an increase in the secretion of insulin by pancreatic islet cells, also reflecting the possible existence of insulin resistance, commonly found in pre-diabetes, type 2 diabetes mellitus patients and the obese population, and need to find out the cause in time, to prevent the pancreatic islet function from being further damaged. When fasting insulin and c-peptide are found to be high, you should consult a doctor in time, and be guided by a professional doctor for life and medication.