Glycogen is basically stored glucose[1], available for use by the body as an energy source. Its main storage points are in the liver and muscles[2]. The glycogen stored in the liver is more readily available to the body than muscle-stored glycogen. Up to 10% of the total weight of the liver can consist of glycogen[3]. When all glycogen storage areas are full, the body then begins turning glucose into fat in a process called lipogenesis[4].

The transformation of glucose into glycogen is called glycogenesis. When the system taps its stored glycogen[5], turning it back into glucose, the process is called glycogenolysis.

The hormone glucagon is sometimes used in the treatment of hypoglycemia. Its value in this is to prompt the liver to release its stored glycogen, turning it back into glucose. If the stores of glycogen are depleted, glucagon would not be useful, as there would be nothing available for the hormone to release[6].

The illlustration below shows the metabolic paths of glucose[7].


  1. Virtual Chembook-Elmhurst College-Glycogen
  2. The Genetic Landscape of Diabetes
  3. Indiana State University: Glycogen
  4. The Genetic Landscape of Diabetes
  5. Biology Pages: Carbohydrates
  6. DC Academy of Veterinary Medicine--Lecture Notes
  7. National Institutes of Health (US) Illustration of Metabolic Paths of Glucose
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