Insulin Resistance vs. Diabetes: Explaining the Differences
Medically reviewed by Danielle Weiss, MD
Insulin resistance, also known as impaired insulin sensitivity, is when your muscle, fat, and liver cells do not respond well to the insulin in your body. Prediabetes is when your blood glucose levels are higher than normal but not high enough to be diagnosed as type 2 diabetes.
Insulin resistance can lead to prediabetes and eventually type 2 diabetes, but not all people with insulin resistance progress to type 2 diabetes.
This article reviews insulin resistance and diabetes, including similarities and differences, symptoms, treatment, and monitoring.
Photo composite by Amelia Manley for Verywell Health; Getty Images
Insulin Resistance vs. Diabetes Quick Facts
Insulin resistance and diabetes are connected, though they are not the same. Below are similarities and differences between the two.
Similarities
Insulin is a hormone made in the pancreas that helps glucose (sugar) exit the bloodstream and enter cells to be used for energy. The body’s ability to make and use insulin is associated with both insulin resistance and diabetes.
Insulin resistance is when the cells in your body do not respond well or are resistant to the insulin being sent from the pancreas to help remove glucose from the bloodstream. When this happens, the pancreas usually responds by making and sending more insulin to try to get a response. This results in high insulin levels in the bloodstream.
Over time, insulin resistance can lead to prediabetes. If care is not taken to reverse it, it can progress to type 2 diabetes. The more insulin resistance someone with diabetes has, the harder it can be to manage blood glucose levels.
Diabetes is when blood glucose levels are too high because the pancreas does not produce enough insulin or the body does not properly use the insulin it makes.
You can’t tell by simply looking at someone if they have insulin resistance or prediabetes. However, insulin resistance and type 2 diabetes have similar risk factors. Aside from family history and genetics that can play a role in both conditions, additional risk factors include increasing age and lifestyle factors such as physical inactivity, diet, and being overweight or having obesity.
Some medications for type 2 diabetes aim to make cells more sensitive to insulin (the opposite of insulin resistance). For example, metformin is a commonly used medication for increasing insulin sensitivity.
Insulin-sensitizing medications can help manage both insulin resistance and type 2 diabetes.
Differences
While there is overlap between the two conditions, not everyone with insulin resistance has diabetes; nor does everyone with diabetes have insulin resistance.
Though insulin resistance can progress to prediabetes and, eventually, type 2 diabetes if left unmanaged, it’s also associated with other medical conditions. These include polycystic ovary syndrome (PCOS), metabolic syndrome, metabolic dysfunction-associated steatotic liver disease, and cardiovascular (heart) disease.
Type 2 diabetes is a chronic medical condition. It is generally not reversible, but options such as lifestyle changes and metabolic surgery may help type 2 diabetes go into remission.
On the other hand, insulin resistance is not necessarily a chronic condition and can be reversed.
Insulin and Type 1 Diabetes
Insulin resistance does not cause or lead to type 1 diabetes. Type 1 diabetes is an autoimmune condition in which the body attacks the beta cells in the pancreas that produce insulin. People with type 1 diabetes make very little or no insulin.
Because of this, they need to take insulin via injection, inhaler, or an insulin pump in order to survive. However, people with type 1 diabetes can develop insulin resistance over time.
How to Tell If You Have Insulin Resistance
There is no single test used to diagnose insulin resistance. Some methods exist to estimate insulin resistance. The most accurate test is complex and reserved for research.
To assess whether you might have insulin resistance, a healthcare provider may order blood tests, such as fasting insulin or an oral glucose tolerance test (OGTT). They might also order blood tests to check your cholesterol (total, high-density lipoprotein, and low-density lipoprotein) and triglyceride levels.
In addition to the results of the blood tests, a healthcare provider may take into account your medical history and current symptoms to determine if you have insulin resistance.
Symptoms
Oftentimes people with insulin resistance have no noticeable symptoms. Nevertheless, there are some things to look out for if you suspect you have insulin resistance. These include:
Acanthosis nigricans (darkened skin in the armpit or on the back and sides of the neck)
Skin tags (small skin growths)
Blurred vision or other eye problems
Weight gain
Hirsutism (abnormal growth of hair on a person's face and body, especially in females)
How to Tell If You Have Prediabetes
Prediabetes is often diagnosed using a blood test, such as fasting plasma glucose (FPG) level or an A1c test (which indicates the average of your blood glucose levels over the past two to three months). The following test results indicate prediabetes:
FPG: 100 to 125 milligrams per deciliter (mg/dL)
A1c: 5.7% to 6.4%
Less commonly, a healthcare provider may use the oral glucose tolerance test (OGTT) to test for prediabetes. This involves drinking a sugary (glucose-filled) beverage and having your blood drawn two hours after drinking the beverage. A diagnosis of prediabetes may be made if your glucose level comes back between 140 and 199 mg/dL after an OGTT.
Symptoms
Most people with prediabetes don’t have any noticeable symptoms. If people with prediabetes have insulin resistance, they may experience the symptoms described above.
As prediabetes progresses to type 2 diabetes, symptoms of high blood glucose may develop, such as:
Increased thirst
Frequent urination
Increased hunger
Extreme fatigue
Blurred vision
Cuts or bruises that are slow to heal
Tingling, numbness, or pain in the extremities (hands and feet)
When Does Insulin Resistance Progress to Diabetes?
As insulin resistance progresses, the cells in the pancreas that make insulin can wear out. When this happens, the pancreas cannot make the amount of insulin needed to properly manage blood glucose levels and keep them in a normal range. Blood glucose levels rise too high, and eventually prediabetes or type 2 diabetes develops.
This progression often happens very slowly and without notice, often taking years. People with prediabetes have up to a 50% chance of developing type 2 diabetes within five to 10 years.
This is why it’s important to engage in healthy lifestyle habits and get regular medical checkups if you have risk factors for either insulin resistance or prediabetes.
Insulin Resistance Without Diabetes
Though it is often an early marker in the development of type 2 diabetes, not everyone with insulin resistance has diabetes.
A study of over 6,200 American adults aged 18 to 44 years old without diabetes found that 40% had insulin resistance. Nearly half of those with insulin resistance did not have obesity.
Having insulin resistance can put you at risk of other medical conditions, or it may occur in other medical conditions. Besides diabetes, insulin resistance is often present in:
Obesity
Metabolic dysfunction-associated steatotic liver disease
Metabolic syndrome
Cardiovascular disease
How to Treat Insulin Resistance vs. Diabetes
The treatment for insulin resistance is often the same as prediabetes treatment. Your healthcare provider may prescribe medication to help your body be more insulin sensitive.
Your healthcare provider may also recommend making changes to lifestyle habits, such as:
Being physically active
Losing weight, if needed
Following a healthy eating pattern
Getting seven to nine hours of quality sleep each night
Eating for Insulin Resistance and Prediabetes
While there is no one specific diet recommended for insulin resistance or diabetes, some healthy eating patterns are often encouraged, such as including the following foods in your diet:
Whole fruits
Vegetables
Lean meats or plant-based protein sources
Whole grains
Beans and legumes
Nuts and seeds
Healthy fats
Some eating patterns that follow this include the Mediterranean diet, the DASH (Dietary Approaches to Stop Hypertension) diet, and the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet.
Limit foods high in added sugars or those with highly refined carbohydrates, saturated fats, and sodium. These often include sweets such as sugar-sweetened beverages, cookies, cakes, donuts, pastries, ice cream, chips, french fries and other deep fried foods, convenience or fast foods, and bacon and other processed meats.
Ongoing Monitoring and Adopting New Habits
If you have one or more other risk factors for diabetes, you should be tested for insulin resistance or diabetes. Even if you don’t have risk factors, experts recommend getting tested for prediabetes once you turn 45 years old. If the results are normal but you have other risk factors, you should be retested at least every three years.
Adopting new lifestyle habits that support health can make a big difference in reversing insulin resistance and delaying or preventing type 2 diabetes. Choose physical activities you enjoy and will engage in regularly, follow an eating pattern that is realistic and includes foods you like, and set a bedtime routine that allows for consistent sleep each night.
Summary
Insulin resistance is when your muscle, fat and liver cells do not respond well to the insulin in your body. Prediabetes is when your blood glucose levels are higher than normal, but not high enough to be diagnosed as type 2 diabetes.
Diabetes is a chronic medical condition in which blood glucose levels are too high. Insulin resistance can lead to prediabetes and eventually type 2 diabetes, but not all people with insulin resistance progress to type 2 diabetes, and not everyone with diabetes has insulin resistance.
Symptoms of insulin resistance include acanthosis nigricans, skin tags, blurred vision, weight gain, irregular menstrual periods, acne, and hirsutism.
Symptoms of high blood glucose levels include Increased thirst, frequent urination, increased hunger, extreme fatigue, blurred vision, cuts or bruises that are slow to heal, and tingling, numbness, or pain in the extremities.
Along with assessing your symptoms and medical history, a healthcare provider can order blood tests, such as fasting insulin and glucose, to determine if you have insulin resistance. Fasting glucose level or an A1c test is often used to diagnose prediabetes.
Insulin resistance can progress to type 2 diabetes when the pancreatic cells that make insulin wear out from producing high levels of insulin, and can no longer make the amount of insulin needed to properly manage blood glucose levels.
Aside from diabetes, insulin resistance may be present in other medical conditions, including obesity, PCOS, metabolic dysfunction-associated steatotic liver disease, metabolic syndrome, and cardiovascular disease.
Treatment for insulin resistance and prediabetes may include medication and lifestyle changes, such as regular physical activity, healthy eating patterns, regular sleep patterns, and losing weight, if needed.
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