Once the creatine is stored inside the muscle cell, it attracts the water surrounding the cell thereby enlarging it. This super hydrated state of the cell causes nice side effects such as the increase of strength and it also gives the appearance of a fuller muscle. Some studies suggest that a super hydrated cell may also trigger protein synthesis and minimize catabolism. In addition, creatine provides for faster recovery in between sets and increased tolerance to high volume work. The way it does this is by enhancing the body's ability to produce Adenosine Triphosphate (ATP). ATP is the compound that your muscles use for fuel whenever they contract. ATP provides its energy by releasing one of its phosphate molecules (it has three phosphate molecules). After the release of such molecule, ATP becomes ADP (Adenosine Diphosphate) as it now only has two molecules. The problem is that after 10 seconds of contraction time the ATP fuel extinguishes and in order to support further muscle contraction glycolisis (glycogen burning) has to kick in. That is fine and well except for the fact that as a byproduct of that mechanism lactic acid is produced. Lactic acid is what causes the burning sensation at the end of the set. When too much lactic acid is produced, your muscle contractions stop, thereby forcing you to stop the set. However, by taking creatine, you can extend the 10 second limit of your ATP system as creatine provides ADP the phosphate molecule that it is missing (recall that creatine is stored in the muscle as creatine phosphate). By upgrading your body's ability of regenerating ATP, you can exercise longer and harder as you will minimize your lactic acid production and you will be able to take your sets to the next level and reduce fatigue levels. More volume, strength and recovery equals more muscle. Creatine also seems to allow for better pumps during a workout. In addition, creatine helps lower cholesterol and triglyceride levels.