Your body uses creatine in energy production. The only source of energy that your body can directly use for muscle contraction is Adenosine triphosphate (ATP), which is generated through three energy systems: the ATP-PCr (ATP-phosphocreatine), glycolytic and oxidative energy systems. The ATP-PCr system is where creatine comes in.
The ATP-PCr system sustains your muscles’ energy needs for three to 15 seconds. The phosphocreatine in your muscles is immediately available when you begin your exercise, and can help to re-synthesise ATP at a high rate, which corresponds to a high power output. However, this system has a severely limited capacity, which means, without creatine supplementation, it’s at a major disadvantage. As the total amount of energy that the system makes available is so small, you can rapidly experience fatigue.
During intense exercise, your PCr stores become depleted. This means that there is less energy available because your body can no longer re-synthesise ATP at the rate required to sustain high-intensity exercise. Your PCr stores can even become depleted almost completely during very intense exercise, and so you lack the ability to maintain maximal effort for exercise. Creatine supplementation works by increasing the rate of ATP re-synthesis during and following your high-intensity, short-duration exercise, meaning that you have a greater ability to maintain maximal intensity exercise and work per bout or set, and a quicker recovery time.
According to the International Society of Sports Nutrition (ISSN), within established guidelines, the use of creatine is safe, effective and ethical. They report that hundreds of studies have shown the effectiveness of Creatine Monohydrate (CM) supplementation in improving anaerobic capacity, strength, and lean body mass in conjunction with training, as well as being possibly beneficial in preventing injury. The ISSN recommends consuming 0.3 grams of CM per kilogram of body weight for three days, followed by three to five grams per day, to increase your muscles’ creatine stores.