Difference between Glucose and Fructose

Glucose vs. Fructose

What is Difference between Glucose and Fructose? Sugar can take many forms such as sucrose, glucose and fructose. If we look for the lowest common denominator, then we would simply have glucose and fructose because these two monosaccharides are the basic elements to create sucrose.

Difference between Glucose and Fructose

There are many similarities between glucose and fructose. Both are simple sugars, and they are monosaccharides. Simple sugars contain only one type of carbohydrate instead of two such as sucrose disaccharide. The chemical formula of glucose and fructose is the same also: C 6 (H 2 O) 6. Once they enter the body, both sugars eventually go to the liver to be metabolized. Most processed and natural foods contain a combination of fructose and glucose. Even the foods that you would expect to be almost all fructose like high fructose corn syrup actually have a composition of 55% -45% total fructose.

However, there are a few key ways in which these two sugars differ.

Molecular Composition

  • While its chemical formula is the same, the molecules of glucose and fructose are established in different formations. Both begin by forming hexagons with their six carbon atoms. Each carbon is attached to a molecule of water.
  • Glucose – It is an aldohexose. Its carbon is bound to a hydrogen atom by a single bond and to an oxygen atom by a double bond.
  • Fructose-It’s a ketohexose. Its carbon is bound only to a hydrogen atom by a single bond.


As mentioned above, both sugars go to the liver. Nevertheless

Glucose is eaten, it is absorbed into the bloodstream, and it goes to the liver where it is broken down to supply energy to the whole body. The process of decomposition requires insulin.

Fructose is eaten and absorbed but it releases its energy more slowly than glucose. It does not need insulin to be metabolized and therefore it is slightly a better option for diabetics.


Fructose is many times sweeter than glucose. Many people believe that uncooked fructose can be really unbearable, especially when fruits, which are where more fructose is found, are maturing. Once the fructose is cooked it loses a lot of its sweetness. That’s why baking is recommended to use sucrose, or granulated sugar instead of crystallized fructose.


  1. Fructose and glucose are monosaccharides with the same chemical composition but with different molecular structure.
  2. These two sugars are found in some combination in almost all available sugary foods.
  3. Glucose needs insulin for proper metabolization while fructose does not need insulin to be processed.
  4. Raw fructose is many times sweeter than glucose.
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