# Glucagon

Glucagon is a hormone (29 amino acids long) made by your pancreas's alpha-cells. It is released when your blood sugar drops, during long fasts, and after you eat protein, and it is suppressed by glucose and insulin. It acts on your liver to raise blood sugar, by breaking down stored glycogen (glycogenolysis) and making new glucose (gluconeogenesis). During fasting it also tells the liver to make ketones. Think of it as insulin's opposite number, and the glucagon-to-insulin ratio helps set how your liver handles fuel. In type 2 diabetes, something goes wrong: glucagon stays high after meals and resists being switched off by glucose, which worsens high blood sugar. GLP-1 drugs partly fix this by boosting insulin and reining in that excess glucagon. Newer dual and triple drugs that target glucagon, GLP-1, and GIP receptors at once are in development for obesity and metabolic disease.

## Sources

- Unger RH, Aguilar-Parada E, Müller WA, Eisentraut AM. (1970). Studies of Pancreatic Alpha Cell Function in Normal and Diabetic Subjects. Journal of Clinical Investigation. https://doi.org/10.1172/JCI106297
- Armour SL, Stanley JE, Cantley J, Dean ED, Knudsen JG. (2023). Metabolic Regulation of Glucagon Secretion. Journal of Endocrinology. https://doi.org/10.1530/JOE-23-0081

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_Canonical: https://longevity-switzerland.com/en/glossary/glucagon · Part of Longevity Cities · Updated 2026-06-22_