Insulin Fasting

You should get a fasting insulin test if you have signs of insulin resistance, such as weight gain around the belly, dark skin patches (acanthosis nigricans), PCOS, or prediabetes. It is also recommended for people with obesity, metabolic syndrome, or a family history of diabetes, and when unexplained low blood sugar suggests an insulinoma.

Fast for 8–12 hours before a fasting insulin test, drinking only plain water. Avoid tea, coffee, juice, chewing gum, and smoking during the fast, and give your sample in the morning. Take diabetes medicines or insulin after the test unless advised otherwise. Stop biotin supplements 48–72 hours beforehand, as biotin can affect results.

Yes, fasting is required for a fasting insulin test. You should fast for 8–12 hours before giving your sample, drinking only plain water. Avoid tea, coffee, juice, and chewing gum during this time, as any food or drink can raise insulin levels and affect the accuracy of your results.