Could Insulin Resistance Change the Size Of Your Brain?

Insulin resistance has been quite the buzz word in the world in wellness, and for good reason. 

Insulin resistance is a condition in which the body's cells become less responsive to the effects of insulin, a hormone that plays a crucial role in regulating blood sugar (glucose) levels. This resistance leads to an impaired ability of insulin to effectively transport glucose from the bloodstream into cells, resulting in elevated blood sugar levels. While insulin resistance is commonly associated with metabolic disorders like type 2 diabetes, PCOS, Metabolic Dysfunction and thyroid disease, its impact extends beyond just affecting blood sugar regulation. It can also have significant consequences for brain function and what is known as neuroinflammation. 

Impaired Glucose Metabolism

Brain cells, particularly neurons, rely heavily on glucose as their primary source of energy. Insulin resistance can disrupt the normal uptake of glucose by brain cells, leading to insufficient energy supply. This can affect neuronal function, communication, and overall brain activity. So, if you or someone you love is struggling with symptoms like brain fog, fatigue, difficulty completing tasks or having trouble concentrating, rather than taking adderall, we might want to make sure we are screening for metabolic dysfunction including insulin resistance. 


Insulin resistance has been linked to chronic low-grade inflammation throughout the body, including the brain. This neuroinflammation can impair brain function and contribute to cognitive decline. Inflammation can damage neurons, disrupt neural networks, and interfere with neurotransmitter balance. All of which can be improved when addressing the root cause, insulin resistance. 

Blood-Brain Barrier Dysfunction

The blood-brain barrier is a protective barrier that separates the bloodstream from the brain tissue. Insulin resistance can compromise the integrity of this barrier, allowing molecules that shouldn't normally enter the brain to cross. This can result in the accumulation of toxins and harmful substances in the brain, further contributing to cognitive dysfunction.

Impaired Signaling Pathways

Insulin is not only involved in glucose uptake but also in various signaling pathways in the brain that are critical for memory, learning, and cognitive function. Insulin resistance can disrupt these pathways, affecting synaptic plasticity (the brain's ability to adapt and learn) and leading to cognitive deficits.

Increased Risk of Neurodegenerative Diseases

There is a growing body of research suggesting a link between insulin resistance and an increased risk of neurodegenerative diseases such as Alzheimer's disease. Insulin resistance may contribute to the formation of beta-amyloid plaques and tau tangles, which are characteristic features of Alzheimer's disease.

Hormonal Imbalances

Insulin resistance can lead to dysregulation of hormones related to appetite, metabolism, and stress, such as leptin and cortisol. These hormonal imbalances can indirectly impact brain function by affecting mood, cognition, and overall mental well-being.

Impaired Neurogenesis

Neurogenesis refers to the generation of new neurons in the brain. Insulin resistance has been associated with reduced neurogenesis, which could hinder the brain's ability to adapt, learn, and form new memories.

Effect on Neurotransmitters

Struggling with anxiety or depression? It might be because you have insulin resistance. Insulin plays a role in the regulation of neurotransmitters like serotonin and dopamine, which are essential for mood regulation and cognitive function. Insulin resistance can disrupt the balance of these neurotransmitters, potentially contributing to mood disorders and cognitive impairment.

If you have thyroid disease, metabolic dysfunction or PCOS and have not had your doctor test for insulin resistance, it is a must! One important biomarker score we can use to better evaluate how well the body is using insulin is by calculating your HOMA-IR score. HOMA-IR stands for Homeostatic Model Assessment of Insulin Resistance. 


HOMA-IR is a tool that doctors, like myself, use to measure how well a person's body is responding to insulin. It's like a little math formula that uses blood tests for glucose (sugar) and insulin levels. By plugging these numbers into the formula, we can get an idea of whether a person's body is having trouble using insulin properly.


Although a relatively inexpensive test, too often this type of comprehensive assessment is rarely ordered on a standard annual blood panel. Make sure to specifically advocate with your doctor for assessing your insulin status including a serum insulin and serum glucose so you too can get a head start on addressing your insulin resistance and ideally improving your brain function along the way! 

About the Author: Meet Dr. ZenAlissia Zenhausern- Pfeiffer, NMD, FABNE, (commonly known by her patients as Dr. Zen), is a licensed naturopathic doctor board certified in naturopathic endocrinology and the founder of NMD Wellness of Scottsdale, a premier naturopathic medical practice that focuses on helping women to take a proactive approach to their hormone and fertility health. Dr. Zen has been featured as a lead expert in Forbes, Shape Magazine, and Instyle and is deeply passionate about bridging the gap between traditional and natural medicine in the world of fertility. She works with a variety of hormone related issues including PCOS, endometriosis and unexplained infertility. Her goal is to help more women get back into the driver’s seat of their own health to make lasting transformational changes to their health to bring more cute and adorable babies into this world. Read More About Dr. Zen...