Creatine is a precursor to the bio-energetic fuel creatine phosphate, which replenishes cellular ATP (adenosine triphosphate) levels during maximum intensity contractions. Supplementing with creatine can increase levels of creatine phosphate in the muscle improving work output capacity, power, recovery and muscle hydration. When muscles are hydrated, muscle catabolism (breakdown) is minimized.
Creatine is one of the most researched and important sports supplements today. It has become a must for athletes wanting to increase workout intensity while delaying the onset of fatigue. Research has shown that supplementing with creatine can boost muscle size, strength and endurance, improve athletic performance, and speed muscle recovery. Saturating your muscles with creatine improves your body's ability to quickly replenish and recycle ATP, which increases muscle energy and delays muscle fatigue. Studies show that when athletes supplement with creatine while weight training, they can quickly gain lean body mass and strength.
Lactic acid is a bi-product from anaerobic (without oxygen) exercise, such as weight training. Lactic acid is responsible for the 'burning' sensation when the muscle becomes fatigued. When you cannot train anymore, it is due to you either having run out of energy or a buildup of lactic acid. Creatine may act as a buffer for this lactic acid, which helps to delay the onset of fatigue.
It has been demonstrated that creatine may also promote muscle growth by stimulating protein synthesis in two ways. Firstly, from the increased work you are able to do as a result of its energy replenishing actions. Secondly is that the more creatine phosphate (CP) that is stored in muscle, the more water is drawn into muscle making it fuller and stronger. With more CP and water in muscle, the volume increases, and the muscle cell is volumized or 'super-hydrated'. A volumized muscle helps to trigger protein synthesis, minimize protein breakdown and increase glycogen synthesis (Haussinger 1996; 1996). If a muscle is then trained properly, this could lead to enhanced muscle growth. The muscle 'pump' experienced when using creatine is reported to be much more intense, and this is as a result of the cell volumizing effect.