How is glucose used by the brain and nervous system?

Glucose serves as the principal fuel source for the brain and nervous system, providing the essential energy required for cell function.123

Because the brain and nervous system rely on a consistent supply of this simple carbohydrate, the body maintains blood glucose levels within a narrow range through hormonal regulation. Insulin facilitates the movement of glucose into cells, while hormones such as glucagon and epinephrine help mobilize glucose from storage when needed.1

The body stores a limited amount of glucose as glycogen in the liver and muscles, which can be released during fasting or physical stress. Additionally, the liver can synthesize glucose from non-carbohydrate sources through a process called gluconeogenesis to ensure the brain receives a steady supply. If blood glucose levels fall too low, a condition known as hypoglycemia, it can lead to symptoms like dizziness and weakness, underscoring the vital importance of glucose to neurological health.134