Glycogen is a polysaccharide molecule that stores energy for animals and fungi. Glycogen is made in the liver and muscles in humans, and its main function is long term energy storage. Glycogen is very similar to starch, a glucose polymer in plants. It is found in the cytoplasm of most cells, and is very important in the glucose cycle. The Fructose from most high fructose products such as syrup can be converted to derivatives of glucose such as glycogen and stored in the liver; which is not harmful if you’re physically active. In fact, most body builders add a little bit of high fructose syrup into their shakes to restore the glycogen in their muscles.