Two tanks with very different jobs
The body stores carbohydrate as glycogen in two main places. The liver holds a smaller amount, often cited near 100 grams, and acts as a systemic reserve: it can release glucose back into the blood to keep levels stable for the brain and the rest of the body, especially between meals and overnight. Muscle holds far more in total, often cited near 400 grams across the body, but it is a local supply.
Muscle lacks the enzyme needed to release free glucose into the bloodstream, so muscle glycogen fuels that muscle's own contractions and cannot be shared with other tissues.
How both tanks refill after eating
After a carbohydrate meal, rising glucose and insulin promote glycogen synthesis, topping up both stores. Liver glycogen responds to overall blood glucose, while muscle glycogen refills fastest in muscles that were recently exercised. The figures above are typical approximations and scale with body size and training status.
This is general educational information, not medical advice. Glycogen storage disorders and metabolic conditions exist and are managed by qualified professionals.