ATP is the primary energy source in the body and supports effective muscle contraction. Creatine improves physical performance in successive bursts of short-term, high intensity exercise such as weight training.
Creatine is involved in a system known as the creatine phosphate system. This phosphate group can readily replenish other molecules that lose theirs and need a replacement, and the most notable and relevant example of this is replenishing ATP (adenosine triphosphate) from ADP (adenosine diphosphate). ATP is the main ‘energy source’ of a cell. Creatine lets you replenish ATP directly without needing to go through a lengthy process of breaking down other molecules into it. Creatine is naturally occurring in meat and other food sources, but monohydrate is the best form because it contains more creatine than other forms. Creatine monohydrate is known as one of bodybuilding's ultimate supplements, and for good reason!