If blood glucose level is high, how does it return back to normal?

When a high blood glucose level is detected by the body, pancreas releases the hormone, insulin, into the bloodstream. The release of insulin results in glucose moving from the blood and into liver and muscle cells. Once glucose moves into the liver and muscle cells, it is converted to glycogen. By converting the glucose into glycogen, it can be stored within the cells. Due to this action, there is now less glucose in the blood, meaning the blood glucose level returns back down to normal levels.