How GLP-1 Affects the Brain, Part 2: GLP-1’s Role in Alzheimer’s Risk and What Research is Learning

August 20, 2025

GLP-1 medications like Ozempic, Wegovy, Mounjaro, and others have quickly become household names.  They’ve changed the weight loss industry and shown promising effects on metabolism and long-term health.  But beyond the scale, there’s another conversation brewing — how do these drugs impact the brain? 

  • In Part 1 of this series, we broke down what GLP-1 weight loss medications are, how they work, and the side effects you should know about, especially surrounding nutrition and muscle loss.   

  • Today in Part 2, we’re zeroing in on the brain — from short-term side effects like brain fog and mood shifts to exciting recent research on GLP-1s and Alzheimer’s disease.  We’ll explore what science tells us so far, what’s still unclear, and why these drugs may ultimately be a double-edged sword for brain health.  Lastly, we’ll share practical tips to support your brain and overall wellness while taking GLP-1 medication, including lifestyle hacks and nutrition strategies. 

(Note:  GLP-1 medications are also called, GLP-1s, GLP-1 receptor agonists, or GLP-1 RAs, which we sometime use below.) 

Recapping GLP-1 Side Effects 

First, let’s review some GLP-1 side effects people should be aware of:  

  • Loss of lean muscle: Almost half the weight lost on semaglutide (Ozempic, Wegovy) and a quarter of the weight on tirzepatide (Mounjaro, Zepbound) comes from lean muscle tissue, not just fat.1  This muscle loss can weaken metabolic health, reduce bone density, and impair physical strength — all of which play a role in healthy aging and brain resilience. 

  • Gastrointestinal issues: Nausea, constipation, reflux, and dry mouth are among the most common reasons people discontinue GLP-1 therapy.2  Persistent GI distress can disrupt nutrition and hydration, both of which are critical for cognitive function. 

  • Thyroid and pancreatic concerns: Though rare, GLP-1 medications have been linked to medullary thyroid carcinoma and acute pancreatitis.3  Both conditions affect overall health and can indirectly impact brain function through inflammation and metabolic stress.  

  • Nutrient deficiencies: Appetite suppression can significantly reduce intake of essential vitamins and minerals.  Research shows notable declines in iron, magnesium, calcium, potassium, vitamins A, C, D, E, K, B12, and omega-3 fatty acids after 12 months of GLP-1 use.4,5  These nutrients are crucial for energy production, neurotransmitter synthesis, and brain cell repair. 

How These Effects Can Impact the Brain 

Since your brain relies on a steady supply of nutrients, oxygen, and metabolic balance, the side effects from GLP-1s can lead to: 

  • Brain fog and mental fatigue: Often linked to low B vitamins, omega-3 deficiency, and undernourishment, these symptoms can make daily concentration and focus more difficult.6    

  • Mood shifts: Deficiencies in magnesium, vitamin D, and omega-3 fatty acids are associated with irritability, anxiety, and low mood, as these nutrients play important roles in balancing neurotransmitters – your brain’s chemical messengers, such as dopamine and serotonin.5    

  • Memory blips over time: Long-term deficiencies in B12, choline, and antioxidants can disrupt brain cell communication and increase oxidative stress in the brain, impacting recall and processing speed.6   

Side Effects Impact How Long People Stay On 

It’s no surprise that side effects, including the ones regarding brain health and cognition, impact how long people keep taking or adhere to GLP-1s.  It seems to depend on the purpose for which people take GLP-1s.  Adherence is significantly lower among those using GLP-1s for weight loss versus those using them to manage type 2 diabetes — one study found that about 65% of patients without type 2 diabetes discontinued GLP-1 therapy within one year, compared to 47% of patients with type 2 diabetes.7    

While side effects show how GLP-1s can influence the brain both directly and indirectly in a negative sense, the question remains:  Can GLP-1s positively impact cognition and brain health? 

Can GLP-1's Affect the Brain in a Good Way? 

The duration of using a GLP-1 RA can shape its potential effects on brain function.   

Managing diabetes, losing excess weight, and improving overall cardiometabolic health are all brain healthy, and if GLP-1 RAs can help with these, shouldn’t they be brain healthy as well?  That could be the case. 

Short-Term Brain Effects 

Early on, GLP-1 RAs can dampen food cravings and disrupt the dopamine-based reward cycle that typically drives overeating.8  Plus, these drugs improve blood sugar control, which helps to reduce fatigue caused by post-meal spikes and crashes, especially in those with insulin resistance or diabetes.9   

Long-Term Brain Effects Create Research Interest 

GLP-1 hormone receptors are found throughout the brain in areas involved in memory and mood, giving researchers a hint on their role in brain health.  Activating these receptors may help reduce brain inflammation — a catalyst to many neurodegenerative diseases — while also encouraging the growth of new neurons in the hippocampus, the brain’s learning and memory region.10  Additionally, GLP-1 activity may protect neurons from oxidative stress and age-related damage.10

These findings are the crux of why researchers are investigating GLP-1 medications for Alzheimer’s disease, Parkinson’s disease, and other conditions marked by progressive cognitive decline.  The possibility of a drug that could help both metabolic and brain health is exciting, but as with all promising treatments, the whole story is more complicated. 

GLP-1 and Brain Aging and Disease: What the Research Shows for Alzheimer’s Disease  

While age is the most significant risk factor for Alzheimer’s disease, underlying issues like brain inflammation, insulin resistance, metabolic syndrome, and vascular problems all play a role.  GLP-1s have caught attention in Alzheimer’s research because they modulate brain insulin signaling and systemic metabolism — two factors deeply intertwined with such underlying issues. 

When insulin sensitivity improves, the brain’s response to insulin tends to improve with it.  Better glucose control also lowers oxidative stress and chronic inflammation, and maintaining a healthy weight supports the blood vessels that feed and protect the brain.  That matters because obesity in midlife is linked with higher dementia risk, likely through these same inflammatory and vascular pathways.11  GLP-1s target these metabolic pathways, so it makes sense to explore whether they could slow or prevent brain decline.  

This may be a surprise, but the idea of using GLP-1 drugs for Alzheimer’s isn’t new — it’s been discussed in scientific literature for over 20 years.12  Interest has spiked recently due to the surge in GLP-1 prescriptions for weight loss, making it easier to observe brain effects in large populations. 

Looking at Promising Findings from Recent Studies 

1. Potential to Reduce Alzheimer’s-Related Pathological Proteins 

GLP-1 RAs may help reduce the accumulation of tau and amyloid beta — the two hallmark proteins of Alzheimer’s that form damaging tangles and plaques in the brain.  This has been observed in many animal studies.13  If these proteins keep building up, they can disrupt neural communication and trigger widespread brain cell death. 

2. May Combat Brain Shrinkage 

In 2024, researchers reported that GLP-1 treatment appeared to reduce shrinkage in certain parts of the brain in Alzheimer’s patients by nearly 50% compared with placebo over a one-year period.14

  • Important note: This finding applies to patients with already-diagnosed Alzheimer’s, not to people looking to prevent the disease. 

3. Improves Related Risk Factors 

GLP-1s have also been shown to reduce the severity of sleep apnea — a condition strongly linked to faster cognitive decline and Alzheimer’s progression.15

Reasons for Caution 

Not all the data points in the same direction, though.  Several recent Alzheimer’s clinical trials with GLP-1s have not shown clear improvements in cognitive test scores or consistent reductions in tau and amyloid beta, despite some positive changes in brain metabolism and inflammation.16  For example: 

  • Multiple trials in Alzheimer's patients found that GLP-1 receptor agonists did not reduce levels of amyloid beta plaques or tau tangles, nor did they improve cognitive performance, despite showing favorable metabolic effects.16 

  • In one trial, liraglutide prevented the expected decline in brain glucose metabolism but did not produce measurable changes in amyloid or cognitive test scores.16 

While GLP-1s hold promise, the evidence is not yet strong enough to call them an Alzheimer’s treatment or proven prevention tool. 

GLP-1:  A Double-Edged Sword for Brain Health? 

Summing it up, like any powerful medication, GLP-1 receptor agonists come with benefits and risks.   

On the upside:  Early research suggests they may improve brain insulin signaling, lower inflammation, protect blood vessels, and even encourage new neuron growth — all potentially protective against Alzheimer’s.17  

But on the downside:  Appetite suppression often leads to nutrient deficiencies in vitamins, minerals, and fatty acids that support memory, mood, and nerve function.  This could contribute to the mentioned side effects of brain fog, mood swings, and even faster cognitive decline, which are some of the very issues we hope to prevent. 

We still have many unanswered questions about ideal dosing, duration, and who benefits most, such as whether APOE4 gene carriers may respond differently.  For now, it’s best to think of GLP-1s as a promising but complex tool — one that requires careful management to maximize benefits and minimize risks. 

How to Support Your Brain While On GLP-1 or Any Weight Loss Regimen   

Let’s bring this back to your day-to-day life.  Whether you’re new to GLP-1s, been on them for a while, or are pursuing a different weight loss path, here are some research-backed, easy-to-implement hacks to protect your brain and body: 

Lifestyle Tips 

  • Exercise: Regular strength training preserves muscle mass and metabolism, supporting brain health and maintaining muscle that is commonly lost during GLP-1 use.  Thus, keeping physically active is very important. 

  • Prioritize sleep: Aim for 7-9 hours so your brain can detox and solidify memories. 

  • Challenge your mind: Trying new hobbies, working through puzzles, and even playing music helps activate mental acuity and build cognitive resilience.  

  • Stay socially engaged and mindful: Regular social interaction and mindful practices calm stress, reduce “food noise,” and protect emotional well-being. 

Nutrition & Eating Hacks (Especially with a Reduced Appetite) 

  • Focus on nutrient-dense foods: Eat berries, leafy greens, fatty fish, extra virgin olive oil, and nuts — they’re packed with antioxidants, healthy fats, and brain-boosting nutrients. 

  • Eat smaller, but nutrient-rich meals: Think egg-and-spinach bites, salmon on arugula, or a cup of Greek yogurt with berries and nuts. 

  • Practice mindful eating: Slow down, chew well, and check in with fullness cues to optimize intake. 

  • Take supplements for B vitamins, omega-3s, magnesium, or choline to ensure you’re not missing out on important nutrients.  For broad coverage, add RELEVATE to your diet.  It offers a robust blend of 17 brain-protective nutrients derived from the evidence-backed Mediterranean and MIND diets, that maintain mental clarity, mood stability, and overall cognitive function.  

Consider partnering with a provider or coach who understands both cognitive health and metabolic goals.  A thoughtful, customized approach ensures you're not only losing pounds — but gaining brain longevity. 


For more guidance on adopting a brain protective diet, or simply including more nutrient rich foods in your diet, download our FREE Mediterranean Eating Guide below. 



RELEVATE: Your Brain’s Nutritional Safety Net 

It’s easy to miss key nutrients when your appetite is smaller.  RELEVATE was designed to pick up where diet may be lacking.  With 17 science-backed nutrients from 8 different food groups, it delivers a complete formula of brain-boosting compounds, while also supporting metabolic health, cardiovascular function, immune resilience, and long-term vitality. 

It’s a practical, daily way to help ensure that even when your plate is smaller, your nutrition is still working at full power.  Learn more about RELEVATE and add it to your routine by visiting here. 


Looking Toward the Future of GLP-1 and Brain Health 

GLP-1 RA medications may influence far more than diabetes, weight, and blood sugar.  Early research hints at potential effects on brain health, though we’re only beginning to understand the full picture.  What is clear is that these medications work best as part of a broader approach, including nutrient-rich foods, physical activity, and habits that challenge and protect the brain.  Don’t sacrifice your brain function for the sake of losing weight.  Prioritize habits that support both body and mind throughout your health journey. 

Stay tuned as we continue to track the rapidly evolving science on GLP-1s and brain health. 

References

1. Ryan, D. H. New drugs for the treatment of obesity: do we need approaches to preserve muscle mass? Rev Endocr Metab Disord (2025) doi:10.1007/s11154-025-09967-4. 

2. Wilding, J. P. H. et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity. New England Journal of Medicine 384, 989–1002 (2021). 

3. Elashoff, M., Matveyenko, A. V., Gier, B., Elashoff, R. & Butler, P. C. Pancreatitis, Pancreatic, and Thyroid Cancer With Glucagon-Like Peptide-1–Based Therapies. Gastroenterology 141, 150–156 (2011). 

4. Scott Butsch, W. et al. Nutritional deficiencies and muscle loss in adults with type 2 diabetes using GLP-1 receptor agonists: A retrospective observational study. Obesity Pillars 15, 100186 (2025). 

5. Johnson, B. et al. Investigating nutrient intake during use of glucagon-like peptide-1 receptor agonist: a cross-sectional study. Front Nutr 12, (2025). 

6. Chen, H. et al. Pharmacovigilance analysis of neurological adverse events associated with GLP-1 receptor agonists based on the FDA Adverse Event Reporting System. Sci Rep 15, 18063 (2025). 

7. Rodriguez, P. J. et al. Discontinuation and Reinitiation of Dual-Labeled GLP-1 Receptor Agonists Among US Adults With Overweight or Obesity. JAMA Netw Open 8, e2457349 (2025). 

8. van Bloemendaal, L. et al. GLP-1 Receptor Activation Modulates Appetite- and Reward-Related Brain Areas in Humans. Diabetes 63, 4186–4196 (2014). 

9. Luchsinger, J. A. et al. Glucose-Lowering Medications, Glycemia, and Cognitive Outcomes. JAMA Intern Med 185, 778 (2025). 

10. Roy, A., Dawson, V. L. & Dawson, T. M. From metabolism to mind: The expanding role of the GLP-1 receptor in neurotherapeutics. Neurotherapeutics e00712 (2025) doi:10.1016/j.neurot.2025.e00712. 

11. Flores-Cordero, J. A. et al. Obesity as a Risk Factor for Dementia and Alzheimer’s Disease: The Role of Leptin. Int J Mol Sci 23, 5202 (2022). 

12. Perry, T. & Greig, N. A New Alzheimers Disease Interventive Strategy: GLP-1. Curr Drug Targets 5, 565–571 (2004). 

13. Kong, F. et al. Glucagon-like peptide 1 (GLP-1) receptor agonists in experimental Alzheimer’s disease models: a systematic review and meta-analysis of preclinical studies. Front Pharmacol 14, (2023). 

14. Weight-loss medicine may slow the progression of Alzheimer’s disease. Brain Sciences (2024). 

15. Fessel, J. All GLP-1 Agonists Should, Theoretically, Cure Alzheimer’s Dementia but Dulaglutide Might Be More Effective Than the Others. J Clin Med 13, 3729 (2024). 

16. Liang, Y., Doré, V., Rowe, C. C. & Krishnadas, N. Clinical Evidence for GLP-1 Receptor Agonists in Alzheimer’s Disease: A Systematic Review. J Alzheimers Dis Rep 8, 777–789 (2024). 

17. Teixeira, L. C. R., Luizon, M. R. & Gomes, K. B. Exploring the Role of GLP-1 Receptor Agonists in Alzheimer’s Disease: A Review of Preclinical and Clinical Evidence. Receptors 4, 2 (2025). 

 

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