Insulin

What it is

Insulin is the hormone that moves sugar from your blood into cells for energy. This test measures the amount in your blood.

Why it matters

Insulin levels help assess insulin resistance and the causes of high or low blood sugar.

What high values can mean

A higher value often reflects insulin resistance, where the body makes extra insulin to keep blood sugar in check.

What low values can mean

A lower value can occur when the pancreas makes little insulin, as in type 1 diabetes.

How to improve it

For high insulin from resistance, weight management, activity, a lower-refined-carb diet and good sleep help most.

Food & lifestyle

Fibre-rich whole foods and protein steady insulin demand; sugary and highly refined foods raise it.

Preparing for the testFasting required

Usually measured fasting, often alongside glucose — do not eat for 8–12 hours beforehand.

When to talk to a doctor

Interpreted by a doctor with your glucose and history to understand your metabolic picture.

Related markers

• C-Peptide
• Glucose
• Hemoglobin A1c
• HOMA-IR

Sources

• MedlinePlus (NIH)
• Testing.com (AACC)

Content reviewed on June 26, 2026