High insulin levels (hyperinsulinemia) are most often caused by insulin resistance, where your cells stop responding properly to insulin so your pancreas has to produce more to keep blood sugar normal. Other, less common causes include insulin‑secreting tumors of the pancreas and overgrowth of insulin‑producing cells.

Main medical cause

• In most people, high insulin is driven by insulin resistance in muscle, liver, and fat tissue, which forces the pancreas to release extra insulin to keep blood glucose in a safe range.

• Over time, this state is closely linked with prediabetes and type 2 diabetes and often appears years before blood sugar itself becomes clearly abnormal.

Lifestyle and metabolic factors

• Excess body fat (especially around the abdomen), physical inactivity, and regularly eating large amounts of refined carbs and sugary foods all promote insulin resistance and thus higher insulin levels.

• Weight gain, high triglycerides, high blood pressure, and fatty liver disease commonly travel together with insulin resistance and hyperinsulinemia.

Hormonal, medication, and genetic factors

• Certain hormone conditions (such as Cushing’s syndrome or acromegaly), pregnancy, and chronic stress can worsen insulin resistance and push insulin levels higher.

• Some medicines (for example, corticosteroids and a few psychiatric or blood‑pressure drugs) can raise insulin needs, and genetic or family tendencies can make a person more prone to insulin resistance and high insulin.

Rare direct pancreatic causes

• Insulinomas (insulin‑secreting pancreatic tumors) and nesidioblastosis (overgrowth of insulin‑producing cells) can cause very high insulin with low blood sugar, but these are rare compared with insulin‑resistance–related cases.

• After some types of gastric surgery, abnormal regrowth of insulin‑producing cells can also trigger inappropriate insulin surges.

When to get checked

• Signs that warrant evaluation include unexplained weight gain, strong carb/sugar cravings, fatigue after meals, darkened velvety skin folds (acanthosis nigricans), or a family history of type 2 diabetes or metabolic syndrome.

• A clinician can assess fasting glucose and insulin, A1c, lipids, and sometimes oral glucose/insulin response tests to look for insulin resistance and guide diet, exercise, and medication strategies to lower insulin levels.