What are normal insulin levels for females?

In general, there are no specific insulin levels that doctors and scientists consider “normal.” 

Having a high or low concentration of insulin in your blood could be normal for you. Or, it could point to a medical issue, depending on what else is going on.

When we can’t produce enough insulin to overcome insulin resistance, our blood sugar levels can rise. This increases the risk of developing type 2 diabetes.

Women’s insulin levels — and risk of insulin resistance — can change at certain times, including during pregnancy, during periods, and after menopause.

Thankfully, you can take steps to reduce or even reverse insulin resistance. These include exercising regularly and making changes to your diet. We’ll dive into the details below. 

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What are low, normal, and high levels of insulin?

Doctors and researchers disagree about these classifications for fasting insulin — your insulin level on an empty stomach. 

That’s partly because insulin levels on their own aren’t necessarily a good indicator of general health, or even insulin resistance.

Experts typically check for insulin resistance or prediabetes by testing a combination of other factors, including blood sugar levels.

Another reason why there aren’t agreed upon ranges for insulin levels is that what’s low, normal, or high for one group of people may not be true for another.

Also, because insulin levels are so rarely tested, there aren’t many studies about them. This can mean having to rely on older research for information.

Assessing insulin levels

We measure insulin blood levels in milli-international units per liter (mIU/L) or picomoles per liter (pmol/L).

One source lists normal ranges as either 5–15 or 5–12 mIU/L (30–90 or 30–78 pmol/L), depending on the test the doctor uses.

Also, health conditions such as obesity or diabetes can affect what a “normal” level might be.

One small study from 2000 found that fasting insulin levels of participants without obesity were 5–7 mIU/L (30–42 pmol/L).

The levels for participants with obesity were 13–19 mIU/L (78–114 pmol/L). For people with diabetes, the levels were 13–17 mIU/L (78–102 pmol/L).  

Obesity is a major risk factor for insulin resistance, and many people with diabetes already have it.

Are there any differences between males and females?

There are no clear, significant differences in levels of fasting insulin between males and females.

However, before menopause, females appear to be more sensitive to insulin than males. 

At certain times — like pregnancy and menopause — women can become less sensitive to insulin. This may lead to higher insulin levels than usual. We’ll look at this in more depth below.

Insulin testing

It’s rare for a doctor to test your insulin levels.

To check for insulin resistance or diagnose a disease like diabetes, doctors tend to look at measures of blood sugar, which are easier (and cheaper) to test and interpret. 

But in some situations, the doctor may test your insulin and levels of other substances in your blood to get a clearer picture.

It can be useful to know how sensitive you are to insulin. This is because changes in insulin sensitivity may be a key risk factor for many diseases.

A doctor may also test your insulin and blood sugar if they think you have insulinoma. This means that tumors in your pancreas are causing it to release too much insulin.

If your doctor wants to find out whether you have insulin resistance or diabetes, they’re likely to use one or more of these blood glucose tests: 

• Fasting glucose: This tests your blood sugar levels when you haven’t eaten for at least 8 hours.

• HbA1C: This shows your average blood sugar levels for the past 3 months.

• Glucose challenge: This tests for gestational diabetes during pregnancy.

• Oral glucose tolerance: This checks for insulin resistance, diabetes, and gestational diabetes.

Pregnancy and insulin

During pregnancy, you become increasingly insulin resistant. It leads to your body producing more insulin. These changes allow more glucose into your blood to feed your baby. 

It can also increase the risk of you and your child developing type 2 diabetes later on.

Depending on your location and risk factors, you might get tested for gestational diabetes 24–28 weeks into your pregnancy. 

If you have it, a healthcare professional will help you follow a healthy eating and exercise plan. If this doesn’t lower your blood sugar enough, they may prescribe insulin injections. 

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Menstruation and insulin

Hormone changes during your menstrual cycle can lead to shifts in insulin levels and sensitivity. 

During the luteal phase of menstruation — the 14 or so days before a period — estrogen and insulin levels increase. This can result in reduced blood sugar.

They’ve also seen that having a higher body mass index — your body weight in relation to your height — or having less cardiovascular fitness could upset these rhythms.

Menopause and insulin

Menopause is the point 12 months after your last period. 

One study by ZOE scientists found that on average, women who had been through menopause had higher insulin levels and increased insulin resistance than those who hadn’t. 

After menopause, women also tended to have worse blood sugar control, as well as other factors associated with metabolic diseases, like type 2 diabetes, heart disease, and obesity. 

The relationship between menopause and insulin levels is complex. But there’s growing evidence that these changes are related to a fall in estrogen levels.

To learn more about menopause and how it can change your body, check out the ZOE Science & Nutrition podcast on the topic.

PCOS and insulin

Polycystic ovary syndrome (PCOS) is one of the most common causes of infertility in women. It involves changes in hormones that can stop the release of eggs and lead to irregular periods.

Women with PCOS often also have insulin resistance and an increased risk of developing type 2 diabetes. 

How to reverse insulin resistance

There are things you can do to reduce your risk of insulin resistance — and even reverse it.

Most of these involve improving your diet. It’s partly because regularly eating foods that quickly raise your blood sugar can lead to insulin resistance.

A healthy diet and exercise routine can also help you manage your weight. This is important because having overweight, and especially excess belly fat, is strongly linked to insulin resistance.

So, here are some strategies:

• Move more: During exercise, your muscles absorb up to five times more sugar from your blood, without the need for insulin. And over time, regular, moderate-intensity physical activity can increase your insulin sensitivity.

• Eat high-quality fiber: Eating more fiber can help manage your blood sugar levels. Boost your fiber intake with healthy whole grains, legumes, and leafy greens. Choose non-starchy veggies over root veggies, like potatoes.

• Cut back on sugars and refined grains: Sodas, fruit juices, and many breakfast cereals have high levels of sugar. Refined grains, like white rice and white bread, can quickly raise your blood sugar, too. Ultra-processed foods, like candy, cookies, and cakes, contain both.

• Consider personalized nutrition: The American Diabetes Association recommends the dietary changes above. But it also says that a personalized nutrition plan is the best way to manage insulin resistance and prevent diabetes through your diet. 

At ZOE, we run the largest nutrition science study in the world. Our research shows that a one-size-fits-all approach to our diets doesn’t work.

With our at-home test, you can find out how healthy your gut is, along with how your blood sugar and fat levels change in response to different foods. Using this information, our personalized nutrition program can guide you to the best foods for you and your health goals.

Learn more about how it works and take our free quiz.

Summary

Currently, experts haven’t agreed on a “normal” insulin level for women.

Most of the time, women’s insulin levels aren’t significantly different from men’s. However, there’s good evidence that women are generally more sensitive to insulin.

Exercise and dietary improvements can be effective ways to manage or reverse insulin resistance.