Fasting insulin
DENüchterninsulin
Fasting insulin measures the insulin in your blood after an overnight fast. It reflects three things at once. First, your β-cells' output. Second, how much insulin your liver clears. Third, how sensitive your tissues are to it. A high fasting insulin is one of the earliest signs of insulin resistance. It often shows up before fasting glucose or HbA1c rise. That matches the natural history seen in cohorts like Whitehall II and IRAS. Chronically high insulin (hyperinsulinemia) goes with metabolic syndrome, type 2 diabetes, and higher risk of heart disease and death. A lower fasting insulin generally signals better insulin sensitivity and metabolic flexibility.
Last reviewed:
This definition is educational and is not medical advice, a diagnosis, or treatment. Talk to a doctor about any health decisions. Read our full medical disclaimer