Key takeaways:
Recent large, real-world studies suggest that medications like semaglutide may be linked to a lower risk of dementia, especially in people with Type 2 diabetes.
Earlier studies hinted that semaglutide might slow the progression of dementia, but the most recent large trials found that it did not.
It’s not yet clear how semaglutide affects brain health. While it treats risk factors for dementia (like obesity and diabetes), it may also help decrease inflammation in the brain.
By now, you’ve probably heard of semaglutide in one way or another. This medication is part of a class called glucagon-like peptide-1 (GLP-1) receptor agonists, and it has made many headlines.
There are a few different brand names for semaglutide, and there a few different reasons to take it:
Wegovy (injectable and oral) is FDA approved for weight loss in people over age 12. It’s also approved to reduce the risk of cardiovascular death, heart attack, and stroke in adults with cardiovascular disease and a body mass index (BMI) over 29. Injectable Wegovy is approved to treat metabolic dysfunction associated steatohepatitis (MASH) too.
Ozempic (injectable) is FDA approved for treating Type 2 diabetes in adults. It’s also approved for two other treatments. First, to lower the risk of heart attack, stroke, and heart-related death in people with Type 2 diabetes and heart disease. Second, to lower the risk of worsening kidney problems and heart-related death in people with Type 2 diabetes and chronic kidney disease.
Rybelsus (oral) is approved for treating Type 2 diabetes in adults.
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As experts continue to study semaglutide, it’s becoming clear that it may have even more health benefits. For example, it might also help people quit smoking. Recent studies suggest it could play a role in preventing or delaying dementia too.
People are at higher risk for developing dementia if they have:
Diabetes
Obesity
Heart disease
A history of strokes
So, any treatment that could change that risk would be welcome news.
How might semaglutide (and similar medications) affect dementia risk? Here’s what the research has shown so far.
Can semaglutide prevent both Alzheimer’s dementia and other types of dementia?
To understand the research, it helps to understand dementia a little better. Dementia is a brain condition affecting things like:
Memory
Thinking
Reasoning
Communication
Self-care
Semaglutide side effects: Semaglutide is effective for diabetes treatment and weight loss. But some of its side effects may be too difficult for some people to tolerate.
Is copycat semaglutide safe? If you can’t access or afford Ozempic or Wegovy, compounded semaglutide may seem like a tempting alternative. But is it worth the risk? Here’s what you need to know.
Should you take semaglutide by mouth or injection? One option requires daily dosing, while the other is weekly. Understand the other differences between Rybelsus and Ozempic.
Two common types of dementia among people with diabetes are Alzheimer’s dementia and vascular dementia.
Alzheimer’s dementia might be the most familiar and common type. It occurs when certain proteins, called amyloid plaques and tau tangles, build up in the brain. This buildup disrupts communication between nerve cells, eventually causing them to die.
Vascular dementia also involves the brain, but it’s caused by a condition involving your blood vessels called atherosclerotic cardiovascular disease (ASCVD). This is when blood vessels supplying the brain are damaged. Vascular dementia is a common complication of diabetes. It’s also common after a stroke or ministrokes.
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Recent research suggests that in both types of dementia, certain brain cells that usually help clean up waste die. Without this “clean-up crew,” problems build up in the brain and cause more damage.
Can semaglutide prevent dementia? What the research shows
It’s still too early to say for sure, but a recent flurry of research suggests it might. Evidence from big observational studies is building up. And the results are linking semaglutide (and other GLP-1s) with a lower likelihood of Alzheimer’s dementia, vascular dementia, and stroke in people with Type 2 diabetes.
But these are retrospective studies (meaning they’re looking back at existing data), and they aren’t the best-quality studies to prove a cause-and-effect relationship. To prove that taking semaglutide lowers the risk of dementia, the best studies would be randomized control trials, where people are randomly assigned to take a treatment or not. This helps show the results aren’t due to other factors. But there haven’t been any of these to date.
That’s why, in 2025, researchers ran what’s called a target-trial emulation. This is a kind of “virtual clinical trial” that uses real-world health records to mimic what a randomized study would show. This helps scientists get closer to cause-and-effect answers when real trials aren’t available, but it can’t replace them entirely.
In the recent target-trial emulation, researchers looked at past data from U.S. electronic health records for more than 1.7 million people with Type 2 diabetes. They found that people taking semaglutide had a significantly lower risk of being diagnosed with Alzheimer’s disease compared to people taking other diabetes medications.
While these results are promising, there are a few important things to keep in mind:
This research still doesn’t prove a cause-and-effect relationship. That means we can’t say that taking semaglutide lowers the risk of dementia and stroke in people with diabetes.
These studies only included people with diabetes. So, these results shouldn’t be broadly applied to people without Type 2 diabetes at this time.
It’s still not clear how semaglutide and other similar medications might work to protect the brain from dementia.
Could semaglutide treat early dementia?
While there were some signals that it might, the evidence to date suggests that it doesn't.
Two randomized, controlled trials with oral semaglutide (EVOKE and EVOKE +) looked into whether treatment could slow the progression of dementia in people with early Alzheimer’s disease. These studies involved thousands of people across 38 different countries. The detailed results haven't been released yet, but the study organisers have said they did not show that oral semaglutide slowed the progression of Alzheimer's disease more than a placebo pill. They even cancelled the 1-year extension period of the trials.
How does semaglutide affect dementia risk?
Researchers aren’t sure exactly how semaglutide could affect brain health, but they have some ideas.
Reducing dementia risk factors
One theory is that semaglutide can reduce dementia risk factors. The idea here is that semaglutide has an indirect effect on the brain by how it affects risk factors for dementia. For example, risk factors for dementia include Type 2 diabetes and having a BMI over 30. And semaglutide improves both of these.
But it’s worth mentioning that the U.S. study (the target-trial emulation mentioned above) found a decrease in dementia risk with semaglutide even in people without a BMI over 30. And studies haven’t found similar associations with other types of diabetes medications. So it’s possible that semaglutide protects brain health in ways that extend beyond just weight loss and lower blood sugar levels.
Neuroprotection
Another theory involves neuroprotection, or how semaglutide could possibly protect your brain. Here’s how that works: Medications like semaglutide act on GLP-1 receptors over your whole body to trigger insulin release. But GLP-1 is also a neurotransmitter, or a chemical in your body that delivers messages. These GLP-1 receptors are present in animal and human brains. In animal studies, GLP-1s like semaglutide seem to have a protective effect on the brain. Research suggests they reduce inflammation in the nervous system.
How to lower your risk of dementia
If you have diabetes or excess body weight, you might wonder how you can prevent dementia. It helps to know the risk factors so that you can address the ones you can change.
Some risk factors you can’t change, including your age and genetics.
Other risk factors sometimes can’t be avoided, like:
Brain injury
Depression
Lower education level
Air pollution
But research suggests healthy lifestyle choices can lower your risk of dementia, regardless of your genetic risk. That’s because other risk factors include:
High blood pressure (hypertension)
Excessive alcohol use
Smoking
Not getting enough physical activity
Not having enough social interactions
If you’re concerned about your risk for dementia, speak with a healthcare professional. They can help you better understand your risk and help you make changes to decrease it.
The bottom line
New, large studies suggest people taking semaglutide may be less likely to develop dementia — but those studies can’t prove cause and effect. And, while earlier studies hinted that semaglutide might slow the pogression of Alzheimer’s disease, the most recent large trials found that it did not.
For now, semaglutide remains approved for diabetes, MASH, weight management, and heart- and kidney-health benefits — but not brain health. It’s promising that a medication already helping metabolic health might one day help protect the brain too, but the evidence just isn’t there yet.
Why trust our experts?
References
Adeniyi, P. A., et al. (2023). Ferroptosis of microglia in aging human white matter injury. Annals of Neurology.
Atri, A., et al. (2024). Evoke and evoke+: Design of two large-scale, double-blind, placebo-controlled, phase 3 studies evaluating the neuroprotective effects of semaglutide in early Alzheimer’s disease. Alzheimer’s & Dementia.
Hammoud, R., et al. (2022). Beyond the pancreas: Contrasting cardiometabolic actions of GIP and GLP1. Nature Reviews: Endocrinology.
Lin, H., et al. (2025). Neurodegeneration and stroke after semaglutide and tirzepatide in patients with diabetes and obesity. JAMA Netw Open.
Livingston, G., et al. (2020). Dementia prevention, intervention, and care: 2020 report of the Lancet Commission. The Lancet.
Lourida, I., et al. (2019). Association of lifestyle and genetic risk with incidence of dementia. JAMA.
Nørgaard, C. H., et al. (2022). Treatment with glucagon-like peptide-1 receptor agonists and incidence of dementia: Data from pooled double-blind randomized controlled trials and nationwide disease and prescription registers. Translational Research & Clinical Interventions.
Novo Nordisk. (2024). A research study investigating semaglutide in people with early Alzheimer’s disease (EVOKE Plus). ClinicalTrials.gov.
Novo Nordisk. (2025). Investor presentation, first nine months of 2025.
Novo Nordisk. (2025). Novo Nordisk A/S: Evoke phase 3 trials did not demonstrate a statistically significant reduction in Alzheimer's disease progression.
Sun, M., et al. (2025). Evaluating GLP-1 receptor agonists versus metformin as first-line therapy for reducing dementia risk in type 2 diabetes. BMJ Open Diabetes Research & Care.
Wang, W., et al. (2024). Associations of semaglutide with first-time diagnosis of Alzheimer’s disease in patients with type 2 diabetes: Target trial emulation using nationwide real-world data in the US. Alzheimer’s & Dementia.
Wang, W., et al. (2025). Associations of semaglutide with Alzheimer’s disease-related dementias in patients with type 2 diabetes: A real-world target trial emulation study. Journal of Alzheimer’s Disease.
