If your doctor told you your labs are normal, you could still have insulin resistance. I'm Dr. Natalie Crawford, a board-certified OB/GYN and reproductive endocrinologist, and I talk about hormones every day. In this video, I break down how you know if you have insulin resistance, even if you don't have the classic risk factors, what it does for your health, and what you can start doing right away. Many people think they don't have insulin resistance because it's been checked in their standard labs. A lot of the time, that's just not true. Your doctor is not always testing you for everything, so you really have to know what is being tested.
IN THIS VIDEO:
00:00 Why Every Woman Should Know Her Fasting Insulin
01:09 What Insulin Really Does
01:58 How Insulin Resistance Happens
03:37 Insulin Resistance and Your Ovaries
04:12 Why Normal Labs Can Miss It
04:41 The Fasting Insulin Test to Ask For
06:08 Tip 1: What Happens While You Sleep
06:37 Tip 2: Your Biggest Metabolic Driver
08:03 Tip 3: What to Do After You Eat
08:30 Tip 4: What to Put on Your Plate
08:50 Tip 5: What's in Your Glass
09:05 Tip 6: When Lifestyle Isn't Enough
What does insulin do?
Insulin is a hormone that is released from your pancreas. This is how I explain it to every patient. You eat food, and your food gets broken down into parts. One of those parts is glucose, which is the fuel, or the food, for a cell.
Imagine your cell is your house, and a salesman comes up and knocks on the door. That salesman is insulin. After you eat, food is broken down to glucose and glucose is in your bloodstream. Your pancreas responds appropriately and releases insulin. Insulin knocks on the door of the cell, the cell door opens, and glucose can go in. That means glucose is lower in your blood, and insulin is lower because it has been used up, so things go back to normal. When the system works perfectly, you eat food, insulin is released, and you use it up. They go up and down together.
How does insulin resistance happen?
Insulin resistance starts to happen because the glucose in your blood becomes more elevated. That can be for a variety of reasons. Very often it is the type of food we eat and how frequently we're eating. Ultra-processed foods with a very high glycemic index raise your blood sugar more than other foods do.
You may not know that chronic stress, or not getting enough sleep, can also increase the amount of glucose in your blood. Your body starts to break down stored glucose if it's not certain you're going to get more, or if you're under stress and it needs extra to burn.
So think about what is really happening at the body level. If your blood sees glucose very commonly, your pancreas responds as it's meant to and releases constant insulin. Imagine the salesman coming to your door time after time. If he's always knocking at my door, I'm going to stop answering, and that is what your cells start doing too. They look out the window and say "No thanks" to the salesman.
But glucose is the fuel the cell needs. The cell communicates back, and your liver starts breaking down stored glucose. Suddenly, more glucose goes into the bloodstream. What does your pancreas do? It releases more insulin, so now you have even higher insulin levels. That's the salesman banging on the door. Finally, you get really annoyed, open the door, and glucose can go in.
Insulin resistance is just this. Your body will respond to insulin, but it takes a greater level to do so than would be ideal.
Why does insulin resistance matter for your ovaries and hormones?
This matters because it reflects that you have more glucose in your blood at times, but insulin is also a growth hormone. That means it is causing you to distribute visceral fat, the metabolically active fat in the lower abdomen.
If we want to be really transparent, insulin is inflammatory. And at the ovary, it changes how the ovary responds. Even when the brain sends a proper hormonal signal, the ovary is going to respond differently. I want you to let that sink in. The ovary responds differently, even in the same circumstances, when it has insulin resistance.
Can you have insulin resistance if your labs are normal?
How do you know if you have insulin resistance? When I bring this up to patients, most say, "Oh, I don't have that," or "It doesn't run in my family," or "I don't have PMOS (formerly PCOS), so I don't need to worry about it." Or they'll say, "Well, my doctor checked all my labs, so I'm fine."
That's not true either, because a lot of doctors aren't checking this. Maybe they're simply checking a blood glucose, or a hemoglobin A1c. A hemoglobin A1c gives us an average glucose over three months. Yes, it can be a helpful marker, but it is a later one to turn. One of the most sensitive and easiest markers for insulin resistance is a fasting insulin level.
What is a fasting insulin test, and what is a good result?
A fasting insulin simply tells us how much insulin your body needs at baseline, with no food, to keep its glucose levels steady.
What is so crazy here is that this is one of those circumstances, like ferritin, where the lab range that is normal is not actually optimal at all. You'll sometimes see very large reference ranges on a lab, and a result might be flagged normal. Realistically, many of us want to see much lower levels. I want to see less than 8, and less than 5 is even better. But you'll usually see that 13 can sometimes be an upper limit of normal, or even higher on certain labs.
So this is one where you have to ask for the right test: "Can I have a fasting insulin?" And you have to look at the results, because they won't always be flagged abnormal. This is something you can do right away, and in fact, you should know what your fasting insulin is. No matter if you're trying to get pregnant, going through perimenopause, or just living your normal life and trying to understand your hormones the best, if you don't know your fasting insulin, you do not know.
6 tips to improve insulin resistance
So what should we do about this? A lot of insulin resistance is under your control. There are lifestyle aspects, and there are also medications that we can leverage, and often it's a combination. But I feel like we should always think about the foundational options as the first line. So let's go through some tips for lifestyle activation you can start right away.
Tip 1: Get enough sleep
One of the first things you can do is sleep enough. Sleep of over seven hours improves your insulin sensitivity. What that means is it helps your cells respond to insulin at a lower level. I like to think of sleep as when your body goes and clears things up, but if you're not getting enough sleep, your body will become more insulin resistant. It's as simple as that. This gets harder, of course, if you're starting to have sleep difficulties in perimenopause and beyond, but this is something to start to prioritize right away.
Tip 2: Build and use muscle
Number two is strength training. You may not know that muscle is one of your biggest metabolic drivers. It is a huge site of glucose being used. In fact, it has a transporter called GLUT4, which can use up glucose without needing insulin. I like to think about this as giving glucose a key to the cell. We don't need insulin to act if glucose is getting used up by muscle.
So we want to build muscle, and we want to use muscle. First of all, you can only leverage the skeletal muscle you have, so pick up weights or do body-weight resistance training at least three times a week.
Second, leverage that muscle, especially in times of stress. Stress is one situation where cortisol, an inflammatory hormone, causes your liver to break down stored glucose again, because your survival when running from the bear shouldn't depend on when your last meal was. When you're stressed, your body wants immediate glucose at its disposal so you can run away and survive. Very often, though, we're not stressed by bears right now. It is meetings and difficult conversations, or the internet, or politics, or money.
In these times, when you feel acutely stressed, I really want you to think: before I stress eat or stress drink, I'm going to activate some of this muscle. Ten quick squats is a simple thing you can do to use some of that glucose and get it into muscle without contributing to worsening your insulin resistance. That is what happens with chronic stress.
Tip 3: Walk after you eat
I also want you to think about walking after meals. Again, activating that muscle uses up some of the excess glucose you don't need right after you've had a big glucose load from a meal. It's very easy: 10 to 15 minutes after you eat, take a quick little walk. It's great bonding if you have a partner or family member you can go with. At the very least, try it after dinner, after your biggest meal. It's a way to help your body process that glucose better.
Tip 4: Build your plate around protein, fiber and whole foods
Aim for protein and fiber at every meal, and try to limit some of the extra added sugars and those ultra-processed foods that have a high glycemic index. Real whole foods are the goal. I'm not a stickler about avoiding fruit or high-glycemic-index veggies, this versus that. If you're eating mostly whole foods, you're doing a good job, so just focus on that.
Tip 5: Limit alcohol
We also really want to limit alcohol. Alcohol raises your blood glucose. It also adds to worsening sleep, and it's inflammatory. So none is best, and less is better than more. Do what you can, but if you can take it out, you're probably going to feel better.
Tip 6: Know when medications and supplements can help
There are also a few medications we should discuss, because there's no harm in medications.
Myo-inositol. For all of my patients who are at risk of or have insulin resistance, I have them start taking myo-inositol. It is a signaling molecule involved in the insulin signaling pathway, so it has very few side effects. It's easy to take, and it's an over-the-counter supplement you can use to help improve some of this insulin sensitivity. We usually want to see a 40:1 ratio of myo-inositol to D-chiro-inositol, which are just different enantiomers. You can look on a package and see if it says 40:1.
Metformin. Metformin is a medication called a biguanide, and it improves insulin sensitivity. It can lessen the risk of progressing on to diabetes. It works best when your risk is highest, but it can have some side effects, so I don't always add it for everybody right away. It has been shown to help improve ovulation, and it certainly can improve parameters when you're doing fertility treatment, especially if you have PMOS (formerly PCOS). It is a prescription, and there can be some GI side effects like bloating, nausea and diarrhea, so we usually want to titrate up in the dose. If lifestyle and inositol don't get us there, or we're doing more advanced fertility treatments, this is something we consider adding on.
GLP-1 medications. Another option that is coming about more lately is GLP-1 medications like semaglutide and tirzepatide. These are weight-lowering drugs that also work with improving insulin sensitivity and really changing your metabolic health. GLP-1 is a hormone that is normally made in your body, and we are just trying to improve it. The data in PMOS patients is emerging, but small studies are showing improvements in both weight and insulin resistance, and we have seen restoration of ovulation. I think they can be very powerful, especially if you have added weight to lose, and for insulin resistance that's really hard to treat otherwise.
But it is not a medication you can be on if you're actively trying to get pregnant. We want you to stop these one to two months before trying to conceive and let your body be without them. So they can serve a purpose, but not while you're trying to get pregnant. If you are past that stage of life, this may be a tool that many women have had amazing results on, and it's not something you should do without a doctor's oversight.
Frequently asked questions
Can you have insulin resistance even if you don't have PMOS (formerly PCOS) or a family history?
Yes. This is why I talk about knowing whether you have it even if you don't have the classic risk factors. Many patients tell me they don't have PMOS or it doesn't run in their family, so they don't need to worry. The only way to know is to check your fasting insulin.
Is a normal glucose or hemoglobin A1c enough to rule out insulin resistance?
Not always. A hemoglobin A1c gives us an average glucose over three months, and it is a later marker to turn. A fasting insulin is one of the most sensitive and easiest markers for insulin resistance.
What fasting insulin level is good?
I want to see less than 8, and less than 5 is even better. Some labs list 13 or higher as normal, so look at your number, because it isn't always flagged abnormal.
Can I take a GLP-1 medication while trying to get pregnant?
No. GLP-1 medications are not something you can be on if you're actively trying to get pregnant. I want you to stop them one to two months before trying to conceive and let your body be without them.
I also wrote a whole Substack article on this, so go check it out: The Women's Guide to Insulin
Want to understand your hormones, fertility, and reproductive health more clearly? The Fertility Formula includes an entire chapter on hormone and toxic exposures. Grab your copy at nataliecrawfordmd.com/book.
Natalie Crawford, MD, is a doctor, but she is not your doctor. This content is for general education and is not a substitute for individualized medical care.