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Where do animals store glycogen?

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A biochemical flowchart shows the metabolic pathways for carbohydrate utilization, including glycolysis, the pentose phosphate pathway, and the tricarboxylic acid (TCA) cycle. The diagram traces the conversion of glucose, fructose, and glycerol through various intermediates, leading to energy production, carbon dioxide release, and biosynthesis of amino acids and porphyrins. Key steps and branches are labeled, with colored boxes highlighting biosynthetic outputs. — Carbohydrate Pathways for the utilization of carbohydrates.

In animals, glycogen serves as the primary carbohydrate energy reserve. While it is found in virtually all animal cells, it is stored in particularly high concentrations in the liver and muscle tissues.123

Liver: The liver stores glycogen to help maintain blood glucose levels for the body, releasing glucose into the bloodstream during periods of fasting or when energy demands increase.4
Muscles: Muscle tissue maintains its own glycogen stores, which are degraded locally to provide an immediate source of energy for muscle contraction during physical activity.54