Dextrose/ˈdekstrəʊz/ Definition 1 of 2Pro Tip 1/3Food Ingredient Dextrose is commonly used as a sweetener in processed foods. Check the ingredients; this cereal has dextrose in it. Pro Tip 2/3Energy Source Athletes may consume dextrose for a quick energy boost. After her run, she drank a dextrose-containing beverage. Pro Tip 3/3Corn Origin Remember, dextrose is derived from corn, which is important for those with allergies. He avoids dextrose because he's allergic to corn.