Insulin Resistance vs. Prediabetes: What’s the Difference?

Published October 2, 2024 · Content updated November 12, 2026 · Editorial policy

Perhaps you’ve read that stubborn belly fat, acne, or cravings mean you’re “insulin resistant.” Or maybe a recent blood test came back with the word prediabetes and you’re trying to understand what it means. These terms get mixed up a lot online.

In this article

Here’s the simple version: insulin resistance means your cells respond less well to insulin. Prediabetes means your blood sugar is higher than normal, but not high enough to be diagnosed as diabetes. They’re connected, but they’re not the same thing, and neither can be diagnosed by looking at your weight, skin, or body shape.

What insulin does

Think of insulin as a key. Your pancreas makes it after you eat, and it helps “unlock” cells in muscle and fat tissue so they can take in and use glucose (sugar) from your blood. Insulin also signals the liver to store glucose and reduce its release. Sleep can also affect how your body responds to insulin. Here’s what happens to blood sugar after disrupted sleep.

With insulin resistance, the locks get a bit stiff. Your body needs more insulin to get the same effect, and over time blood sugar can creep up. The NIDDK insulin-resistance guide explains this relationship.

One important point: insulin isn’t a villain. Despite its reputation as a “fat-storage hormone,” you need it to live. A normal rise in insulin after a meal is your body doing its job.

Why you can’t tell by looking

Most people with insulin resistance or prediabetes have no symptoms at all. That’s exactly why online checklists based on body shape, acne, or cellulite are unreliable. Doctors usually check for prediabetes with blood glucose tests, rather than measuring insulin resistance directly, as NIDDK notes.

If acne or weight changes bother you, they’re worth raising with a doctor in their own right. They just aren’t proof of a blood sugar problem, and they’re not a reason to start a supplement.

Understanding the tests

Two common tests give different kinds of information. A fasting glucose test shows your blood sugar at one moment, after not eating. An A1C test estimates your average blood sugar over roughly the past three months, a bit like a highlight reel rather than a live feed. Some conditions can affect A1C accuracy, so results need context. The CDC A1C explanation covers the details.

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The PCOS connection

If you have PCOS, you may have heard that it’s linked to insulin. That’s true: PCOS is associated with a higher risk of insulin resistance and type 2 diabetes. But it isn’t caused by one food choice, and not everyone with PCOS has the same pattern. The WHO overview of PCOS explains the wider health picture. For practical support, read living with PCOS.

What you can do

• Ask about screening if you have risk factors such as PCOS, a family history of type 2 diabetes, or diabetes during a past pregnancy.
• Understand your result. Ask what prompted the test, what the number means for you, and whether you need follow-up.
• Focus on sustainable habits your care team recommends, and ask how progress will be checked.
• Skip products that promise to “reverse” insulin resistance, clear your skin, or shrink your waist.

The NIDDK guide lists risk factors, including family history, past gestational diabetes, and PCOS. Ask which screening schedule fits your history. If you have questions about GLP-1 medicines, here’s what Ozempic does in the body. For other questions about results or prevention, read more on insulin resistance and diabetes. If your questions are about how body shape can change in midlife, rather than about blood sugar, read why body fat can shift around menopause.

Frequently asked questions