The chemical formula for glucose is C6H12O6, with the numbers that follow each element represented in subscript for clarity. Glucose represents one example of a carbohydrate sugar used by the human body for energy.
Glucose can be used by humans in a chemical reaction that combines glucose and oxygen to yield carbon dioxide and water. Energy for a wide variety of human body functions is readily available from the glucose in the blood.
Certain medical conditions such as diabetes or hypoglycemia can present in humans that have too much or too little glucose in their blood. These conditions are often diagnosed by performing laboratory tests on an person's blood.