Your fasting glucose is fine. Your fasting insulin was never run.
You were told your blood sugar is normal. Ask what was tested. If the answer is fasting glucose, and maybe an A1c, you were shown the end of the story and none of the middle. Glucose is the last number to move. Insulin moves first, sometimes for ten years first, and almost nobody runs it.
This is the second most common gap I find in a lab folder, after the thyroid tested at TSH alone, and the two gaps have the same shape. The doctor tested the thing that goes wrong last and called it fine. I want to show you what insulin does before glucose ever changes, why it matters more in your forties, and how to ask for it.
What insulin is doing while glucose stays normal
Insulin is the hormone that moves sugar out of the blood and into the cells. After a meal, glucose rises, the pancreas releases insulin, the cells open, and glucose goes back down. That is the whole loop when it works.
When it stops working, it fails from the cell side first. The cells get slower to answer. So the pancreas sends more insulin to get the same result, and it works. Glucose comes down. Your fasting glucose reads 88 and everyone is satisfied. What nobody saw is that it took twice the insulin to get there.
This can go on for years. The pancreas keeps up, glucose keeps looking fine, and insulin keeps climbing. Fasting glucose only starts to rise once the pancreas cannot keep pace, which is late. By the time an A1c crosses into prediabetes, the insulin problem has usually been there for a long time. A fasting insulin, run next to the fasting glucose, shows you the middle of that story instead of the end.
Receptors decide, hormones only ask
I wrote about this idea in Issue 009 and it applies to every line on the panel. A hormone is a message. The receptor on the cell decides whether the message is heard. Insulin resistance is a receptor problem before it is a sugar problem. There is plenty of insulin. The cells have stopped listening, so the body shouts.
That matters because the things that make cells stop listening are the things I spend my days on. Sleep that is short or broken. A nervous system that never stands down, holding cortisol up, and cortisol's job is to keep sugar available. A gut that is inflamed. Meals that are mostly carbohydrate. Muscle that has been quietly lost, because muscle is where most of your glucose is meant to go. None of those show on a glucose result. All of them show in insulin first.
Why this matters more in your forties
Estrogen helps cells hear insulin. As it falls across perimenopause, insulin sensitivity falls with it, and fat starts to move to the middle. Women who ate the same way for twenty years find their waist changing and their glucose still reading normal. The insulin has moved. Nobody measured it.
High insulin is also a growth signal. It pushes the ovaries toward androgens, which is the PCOS chain, and it drives the liver to store fat and make more triglycerides, which shows up on the cholesterol panel from Issue 010 and on the liver enzymes I will write about soon. It holds on to sodium and raises blood pressure. It makes the inflammation marker climb. If you read the whole folder at once, high insulin is often the one thing pulling every other flag in the same direction. Read one page at a time, it is invisible, because it was never on any page.
The range, and the word normal
Here I have to be careful, because fasting insulin is a less tidy test than glucose. The assays are not standardised the way glucose is, so a result from one lab is not exactly comparable to another, and the printed reference range is wide. Many labs will call anything from about 2 to 25 normal. That range was built from a population where insulin resistance is common, so being inside it says very little.
Most clinicians who work with metabolic health treat a fasting insulin under about 10 as reassuring and consider single digits, especially under 6 or so, the picture you want. Above 10 to 12, with a normal glucose, is the pattern I see most often in the women who come to me tired, heavy around the middle, and told everything is fine. Some doctors combine the two numbers into a score called HOMA-IR: fasting glucose times fasting insulin, divided by 405 if your glucose is in mg/dL. Under about 1 is good. Above 2 to 2.5 is where most researchers start to call it resistance. These are working cutoffs from the literature and not a formal diagnostic standard, so hold them lightly and ask your doctor how they read yours.
One more thing about the test. Insulin is sensitive to the days before the draw. A bad night's sleep, a late meal, a stressful week or a course of steroids can all push it up. Fast twelve hours and skip the hard workout that morning.
What I ask people to get
I do not order tests. I tell you what to ask for by name, and I ask you to get the printout.
Fasting insulin, drawn with the fasting glucose. Same tube, same morning. On its own, glucose tells you the ending. Together they tell you the story.
HbA1c. It reflects the last three months and it is worth having. It can read falsely low if you have iron deficiency or heavy periods, which many women in their forties have, so it is not the whole answer either.
Triglycerides and HDL, from the lipid panel you already had. High triglycerides with a low HDL is the cholesterol pattern that tracks with insulin resistance. If your triglyceride number divided by your HDL is above about 2.5, that is worth raising.
ALT and a waist measurement. A creeping liver enzyme and a waist above 35 inches, in a woman, both point the same way as insulin.
If the fasting insulin is high, ask about a two hour glucose test with insulin measured. It shows what your body does after a meal, which is where the earliest trouble lives.
What I would do first
None of this needs a result to start. All of it helps whatever the number turns out to be.
Thirty grams of protein at breakfast. This is the change people notice fastest, usually within a week. It flattens the morning glucose rise and cuts the afternoon crash that sends you to the biscuit tin.
Something to slow every meal. Protein, fiber or fat with the carbohydrate, every time. Eat the vegetables and the protein first and the bread last. The order alone lowers the glucose peak.
Walk for ten minutes after your largest meal. Muscle pulls in glucose without needing insulin to ask. It is the cheapest insulin sensitiser there is.
Lift twice a week. More muscle means more places for glucose to go. It does not need to be heavy or long. It needs to be regular, and it matters more now than at any age before.
Protect sleep. One short night measurably worsens insulin resistance the next day. Same bedtime, dark room, phone in another room.
Do not fast your way out of this on your own. Long fasts and juice cleanses spike and crash blood sugar, which is the exact thing you are trying to calm. If you have a history of disordered eating, or you take medication for diabetes, changing meal timing is a conversation for your doctor first.
When to push harder with your doctor
Some of this is a lifestyle picture and some of it is a clinical one. Push harder if your fasting glucose is above 100, if your A1c is 5.7 or higher, if your triglycerides are high and your HDL is low, if your waist has grown quickly, if you have PCOS or had gestational diabetes, or if a parent had type 2 diabetes. Ask directly what your options are. Metformin, the newer diabetes medicines and a referral to an endocrinologist are all conversations a doctor can have with you, and if insulin is high and glucose is climbing, that conversation should happen now and not at the next annual visit.
If you are pregnant, the rules and the ranges are different and this note does not apply. If you take insulin or any diabetes medication, do not change what you eat or when you eat without your prescriber, because the dose was set for the meals you have now.
I do not diagnose and I do not treat. I read these numbers next to your sleep, your food, your family and your stress and tell you what I see as one picture. If it needs clinical care I say so and I send you.
Questions I get asked
My fasting glucose is normal. Can I still be insulin resistant?
Yes, and it is the usual pattern. The pancreas keeps glucose normal by making more insulin, often for years. Fasting glucose only rises once the pancreas cannot keep up. A fasting insulin drawn alongside the glucose shows the strain before the glucose does.
What is a good fasting insulin level?
The printed range is wide, often about 2 to 25, and it is not standardised across labs. Many clinicians treat under 10 as reassuring and single digits as the aim. Above 10 to 12 with a normal glucose is worth a conversation. Ask your doctor how they read it, because the cutoffs are working ones and not a formal standard.
What is HOMA-IR?
A score that combines fasting glucose and fasting insulin into one number. Multiply the two, then divide by 405 if glucose is in mg/dL. Under about 1 is good. Above 2 to 2.5 is where most researchers call it insulin resistance. Hold the cutoffs lightly and read them with someone who knows your history.
Why does perimenopause make insulin resistance worse?
Estrogen helps cells hear insulin. As it falls, sensitivity falls with it, fat moves to the middle, and muscle is lost faster unless you work to keep it. That is why women who changed nothing see their waist and their insulin change in their forties.
Does a high fasting insulin mean I will get diabetes?
No. It means the cells have stopped listening and the body is compensating, and that is the stage where food, movement, sleep and a calmer nervous system do the most. Diabetes is what happens when the compensation runs out. The point of testing early is that you get to act while it still works.
If you want it in order
Everything above is the ground floor. The 10 Day Reset is the same work with times on the page, meal plans, worksheets and 79 recipes, for $49, so nothing is left for you to decide when you are tired. Or put your email in below and I will send you the 7 Day Energy Reset, which is free.
This is general wellness education and not medical advice, diagnosis or treatment. Talk to a qualified professional, especially if you are pregnant, nursing, taking medication or managing a condition.