From #1 New York Times bestselling author Dr. David Perlmutter comes a groundbreaking guide to the brain’s immune cells—essential to preventing disease and sustaining peak cognitive function and mental health

We’ve been fighting the wrong enemy. For decades, medicine has pointed its weapons at symptoms like memory loss, tremors, headaches, and lethargy, while ignoring the root causes of diseases like Alzheimer’s, Parkinson’s, and major depression. In Brain Defenders, neurologist Dr. David Perlmutter flips the script, exposing the real culprits: malfunctioning microglia, tiny immune cells that, when metabolically hijacked, go rogue and attack the very neurons they’re meant to protect.
With clarity and urgency, Dr. Perlmutter explains how a silent battle rages in the brain. Microglia can become either warriors of protection or agents of destruction—and the outcome depends largely on how we live. In Brain Defenders, you will:


- Learn the science of immunometabolism and the relationship between energy and your cells
- Understand the overlooked role of inflammation in everything from dementia to long COVID—and why the immune system may be the brain’s greatest threat and hope
- Discover how your lifestyle affects the fate of your microglia and, in turn, your cognitive future
- Uncover the surprising link between metabolic health and brain resilience, and how tools like fasting, sleep, and even oxygen therapy can restore damaged neural networks
- Explore therapeutic interventions—from metformin to lion’s mane mushroom—that support healing and slow neural decline


Neurodegeneration, cognitive impairment, and mood disorders are not inevitable, but often the result of chronic, controllable inflammation. Drawing on the latest peer-reviewed science and grounded in decades of neurological care, Dr. Perlmutter delivers a powerful message: the future of your brain health is in your hands.


* This audiobook edition includes a downloadable PDF containing an M1, M2 Phenotypes chart, a Low Estradiol illustration, a prebiotic food sources list, and lab testing resources.