Why Doesn't My Doctor Test My Fasting Insulin?

You went to your annual physical. You asked good questions. Your labs came back and your doctor said everything looked normal.

But something still does not feel right. Weight that will not budge. Energy that is not there. A feeling that your body is working against you even though you are doing the right things.

This is one of the most common patterns I see in new patients. And one of the most common explanations is a test that almost no one orders.

It is called fasting insulin.

What is fasting insulin and why is it different from fasting glucose?

Your doctor almost certainly tested your fasting glucose. That number tells you how much sugar is in your blood right now.

Fasting insulin is a different question entirely. It tells you how hard your body is working to keep that blood sugar under control.

The reason this matters is that insulin rises long before glucose does. Your body is remarkably good at compensating. It will produce more and more insulin to keep blood sugar in a normal range for years. Sometimes for a decade or longer. During that entire time your fasting glucose looks fine. Your A1c looks fine. Nothing flags.

But insulin is already telling a different story.

Why doesn't my doctor test my fasting insulin?

A few reasons, and none of them are great.

Standard annual physicals were built to catch disease, not prevent it. Fasting insulin is not on the default panel because most medical training focuses on diagnosing diabetes after blood sugar has already risen. Not on catching insulin resistance in the years before that happens.

There is also no universally agreed optimal range for fasting insulin. Most labs report anything under 25 as normal. But research consistently points to under 8 as where metabolic health is genuinely optimized. Most patients never hear that those are two very different numbers.

The test itself is not complicated. It is a standard blood draw. It costs very little. Most physicians will order it when a patient asks directly. The gap is not the test. The gap is that no one thinks to mention it.

What do the numbers actually mean?

Under 25 is the lab reference range. It means you are average relative to the general population.

Under 8 is where the research consistently points for genuine metabolic health. Sitting between those two numbers and being told you are fine is one of the most common situations I see in this practice.

If your fasting insulin is elevated and your glucose is still normal, your body is compensating. It has been compensating for a while. That is not a permanent state. Understanding where you are on that spectrum early is when meaningful change is still straightforward.

How do I get this test ordered?

Say this at your next appointment.

"I would like to add fasting insulin to my blood panel."

That is the whole sentence. Most physicians will order it without hesitation. While you are there, also ask about ApoB and hsCRP. Those three markers together give a picture of your metabolic health that a standard annual physical simply cannot provide.

The test exists. It is available at almost any lab. The only reason most people have never had it is because no one thought to order it. That is a solvable problem.

At White Olive we run a full metabolic panel from the first visit, including fasting insulin, for patients across Calabasas, Westlake Village, Hidden Hills, Malibu, and Woodland Hills.

If you are on Instagram, comment GUIDE and I will send you our free Boost Your Metabolism in 30 Days guide. Or book a free 15-minute intro call at whiteolivedpc.com/booking.

Frequently Asked Questions

Why doesn't my doctor test my fasting insulin?

Fasting insulin is not part of a standard annual physical panel. Most physicians were trained to diagnose diabetes after blood sugar rises, not to catch insulin resistance in the years before. The test is standard and inexpensive and most physicians will order it when asked directly.

What is a normal fasting insulin level?

The lab reference range is under 25. Research suggests that optimal metabolic health looks more like under 8. Most patients are never told these are different numbers. Where you fall between them matters clinically.

Can my fasting glucose be normal and my insulin still be high?

Yes. This is one of the most important things to understand about early insulin resistance. Your body compensates by producing more insulin to keep blood sugar in range. Fasting glucose can look completely normal for years while insulin is already elevated. Fasting insulin catches this pattern earlier than any standard marker.

How do I ask my doctor to order fasting insulin?

Say this at your next appointment: "I would like to add fasting insulin to my blood panel." It is a standard lab. Most physicians will order it without hesitation. Also ask about ApoB and hsCRP for a more complete metabolic picture.