Type 3 diabetes: What it is, symptoms, and what you need to know

You may have heard the term “type 3 diabetes” and wondered if it’s another form of diabetes like type 1 or type 2. The short answer: type 3 diabetes isn’t an official medical diagnosis—but it’s often used to describe Alzheimer’s disease linked to insulin resistance in the brain.

Researchers have found that people with type 2 diabetes are at higher risk of developing dementia, including Alzheimer’s. This has led some scientists to use the term “type 3 diabetes” to highlight the connection between impaired glucose metabolism and brain health.

In this article, we’ll explain what type 3 diabetes means, how it differs from other types of diabetes, the signs to watch for, what science says about the link to Alzheimer’s disease, and what you can do to support your brain and metabolic health.

What is type 3 diabetes?

Unlike type 1 and type 2 diabetes, type 3 diabetes is not a recognized diagnosis by the American Diabetes Association or the World Health Organization. Instead, it’s a research term used to describe:

• Insulin resistance in the brain

• Impaired glucose metabolism in brain cells

• A proposed mechanism behind Alzheimer’s disease

Essentially, “type 3 diabetes” is used to emphasize that Alzheimer’s may be partly caused by the same processes that drive type 2 diabetes: insulin resistance and chronic inflammation.

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Why do some experts call Alzheimer’s “type 3 diabetes”?

Alzheimer’s disease is the most common form of dementia, affecting memory, thinking, and daily function. Scientists noticed that:

• People with type 2 diabetes have a 50–60% higher risk of developing Alzheimer’s.

• Brain scans and autopsies show reduced insulin receptors and glucose metabolism in Alzheimer’s patients.

• Insulin resistance in the brain may contribute to the buildup of amyloid plaques and tau tangles—hallmarks of Alzheimer’s disease.

For these reasons, researchers began referring to Alzheimer’s as “type 3 diabetes” in the early 2000s to draw attention to the overlap.

How is type 3 diabetes different from type 1 and type 2?

Symptoms linked to “type 3 diabetes”

Because the term is tied to Alzheimer’s disease, the symptoms overlap with early signs of dementia:

• Memory problems that disrupt daily life

• Difficulty planning or solving problems

• Trouble completing familiar tasks

• Confusion with time or place

• Difficulty finding words

• Changes in mood or personality

• Misplacing items frequently

If you notice these symptoms in yourself or a loved one, it’s important to seek medical evaluation.

What does research say about type 3 diabetes?

Evidence from studies

• A 2020 review in Journal of Alzheimer’s Disease found strong evidence that insulin resistance and inflammation play major roles in Alzheimer’s progression.

• A 2021 NIH-funded study showed that people with type 2 diabetes who had poor blood sugar control had higher rates of cognitive decline.

• A 2023 clinical trial investigated intranasal insulin therapy and found modest improvements in memory among people with mild cognitive impairment.
  
  

Key takeaway

While “type 3 diabetes” isn’t an official medical condition, the evidence strongly supports a link between diabetes, insulin resistance, and Alzheimer’s disease.

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Who is most at risk?

People may have a higher risk of developing Alzheimer’s (or so-called type 3 diabetes) if they have:

• Long-standing type 2 diabetes

• Poorly controlled blood sugar

• Obesity and metabolic syndrome

• High blood pressure or high cholesterol

• Family history of Alzheimer’s

• Sedentary lifestyle

• Older age (risk rises significantly after 65)
  
  

Can type 3 diabetes be prevented?

While there’s no guaranteed way to prevent Alzheimer’s, research shows that lowering your risk for type 2 diabetes may also reduce your risk of dementia. Helpful strategies include:

• Managing blood sugar: Keep fasting glucose and HbA1c in target range.

• Eating a balanced diet: Mediterranean and DASH diets are associated with lower dementia risk.

• Staying active: Aim for 150 minutes of moderate exercise per week.

• Maintaining a healthy weight: Reduces both diabetes and dementia risk.

• Controlling blood pressure and cholesterol: Important for both heart and brain health.

• Getting quality sleep: Poor sleep is linked to insulin resistance and Alzheimer’s risk.

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Treatment options being studied

Since “type 3 diabetes” is a research term, there’s no official treatment. But ongoing studies are looking at:

• Intranasal insulin therapy – Delivers insulin directly to the brain.

• Diabetes medications – Drugs like metformin and GLP-1 agonists are being studied for potential protective effects on cognition.

• Lifestyle interventions – Exercise, diet, and cognitive training show promise in slowing cognitive decline.

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Final thoughts

So, what is type 3 diabetes? It’s not an official diagnosis—but rather a way researchers describe the connection between insulin resistance, type 2 diabetes, and Alzheimer’s disease. The term highlights how closely brain and metabolic health are linked.

If you’re managing type 2 diabetes or at risk of Alzheimer’s, the good news is that healthy lifestyle choices can lower risk for both. Keeping blood sugar under control, eating well, exercising, and staying mentally active are some of the most powerful steps you can take.

Want to better understand your risk? Ribbon Checkup offers at-home metabolic and liver health tests designed to give you insights you can act on today.

Related Resources

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References

References

Booth, S. (2016, August 31). Type 3 Diabetes and Alzheimer’s: What to Know. Retrieved August 28, 2025, from WebMD website: https://www.webmd.com/diabetes/alzheimers-diabetes-link 

Hobbs, H. (2018, June 28). Type 3 Diabetes and Alzheimer’s Disease: What You Need to Know. Retrieved August 28, 2025, from Healthline website: https://www.healthline.com/health/type-3-diabetes 

Morales-Brown, P. (2021, July 30). What is type 3 diabetes? Retrieved August 28, 2025, from Medicalnewstoday.com website: https://www.medicalnewstoday.com/articles/type-3-diabetes 

Peng, Y., Yao, S., Chen, Q., Jin, H., Du, M., Xue, Y., & Liu, S. (2024). True or false? Alzheimer’s disease is type 3 diabetes: Evidences from bench to bedside. Ageing Research Reviews, 99, 102383. https://doi.org/10.1016/j.arr.2024.102383 

Suzanne. (2014a). Type 3 diabetes is sporadic Alzheimer׳s disease: Mini-review. European Neuropsychopharmacology, 24(12), 1954–1960. https://doi.org/10.1016/j.euroneuro.2014.06.008 

Suzanne. (2014b). Type 3 diabetes is sporadic Alzheimer׳s disease: Mini-review. European Neuropsychopharmacology, 24(12), 1954–1960. https://doi.org/10.1016/j.euroneuro.2014.06.008 

Frequently Asked Questions

Q: Is type 3 diabetes a real medical condition?

A: Not officially. It’s a research term used to describe the link between insulin resistance and Alzheimer’s disease.

Q: Does having type 2 diabetes mean I’ll develop type 3 diabetes?

A: No. Not everyone with type 2 diabetes develops dementia, but risk is higher if blood sugar is poorly controlled.

Q: Can diet prevent type 3 diabetes?

A: A diet rich in vegetables, whole grains, lean protein, and healthy fats may reduce risk of both diabetes and dementia.

Q: Are there tests for type 3 diabetes?

A: No. Doctors use cognitive testing, imaging, and labs to diagnose Alzheimer’s—not “type 3 diabetes.”

Q: What’s the difference between type 3 diabetes and type 3c diabetes?

A: Type 3c (pancreatogenic diabetes) is a recognized form of diabetes caused by pancreatic disease. “Type 3 diabetes” is a research concept tied to Alzheimer’s.