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How is blood glucose kept within a safe range?

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Blood plasma — blood Blood sediment in test tubes, showing plasma (clear fluid), red blood cells (red), and the release of hemoglobin into the surrounding plasma (pink).

Blood glucose levels are maintained within a safe range through a precise homeostatic mechanism primarily regulated by the pancreas via two key hormones: insulin and glucagon.12

When blood glucose rises—typically after eating—the islets of Langerhans in the pancreas release insulin. Insulin lowers blood sugar by promoting the uptake of glucose into muscle and adipose tissue and by signaling the liver to store excess glucose as glycogen while inhibiting the production of new glucose.12

Conversely, when blood glucose levels drop during fasting or exercise, the pancreas secretes glucagon. Glucagon opposes insulin by stimulating the liver to break down stored glycogen into glucose (glycogenolysis) and by producing glucose from non-carbohydrate sources (gluconeogenesis). This negative feedback system ensures that the body maintains a steady supply of energy for its cells.3241