The supplement industry can be confusing. There are thousands of products, many backed by outrageous claims. Worst of all, some supplements are nothing more than expensive junk foods. So, are any worth taking? If I could recommend one supplement, it would be creatine.
What Is Creatine?
The following is a bit on the scientific side, but hopefully it makes sense about what creatine is and why it is one the best supplements on the market. So, bear with me. (Learn more about creatine.)
Creatine is used in energy production. Adenosine triphosphate (ATP) is the only source of energy that can be used directly for muscle contraction. ATP is generated through three energy systems: the ATP-PCr (ATP-phosphocreatine), glycolytic and oxidative energy systems.
The ATP-PCr system sustains muscles' energy needs for three to 15 seconds. Phosphocreatine in muscle is immediately available at the onset of exercise and can be used to resynthesize ATP at a high rate, which corresponds to a high power output. The major disadvantage of this system is its limited capacity. The total amount of energy available is small, so fatigue occurs rapidly.
This energy supplied during and following intense exercise depends largely on the amount of phosphocreatine (PCr) stored in the muscle . As PCr stores become depleted, energy availability diminishes due to the body's inability to resynthesize ATP at the rate required to sustain high-intensity exercise . During very intense exercise, phosphocreatine stores can become almost completely depleted. Consequently, the ability to maintain maximal effort for exercise declines.
Creatine supplementation increases the rate of ATP resynthesis during and following high-intensity, short-duration exercise [2, 3, 4]. The ability to maintain maximal intensity exercise and work per bout or set is greater, and recovery time is quicker.
Is Creatine Effective?
Creatine is one of the most extensively studied and scientifically validated nutritional ergogenic aids for athletes . It is one of the few supplements highly recommended by top sports nutritionists in the United States, people such as Dr. Joan Eckerson, who stated at a sports nutrition lecture I attended that "if your athletes are not taking creatine, they are at a disadvantage." (Learn more about creatine's effects.)
In addition, according to the International Society of Sports Nutrition (ISSN):
The use of creatine as a nutritional supplement within established guidelines is safe, effective and ethical. Despite lingering myths concerning creatine supplementation in conjunction with exercise, Creatine Monohydrate (CM) remains one of the most extensively studied, as well as effective, nutritional aids available to athletes. Hundreds of studies have shown the effectiveness of CM supplementation in improving anaerobic capacity, strength, and lean body mass in conjunction with training. In addition, CM has repeatedly been reported to be safe, as well as possibly beneficial in preventing injury. Finally, the future of creatine research looks bright in regard to the areas of transport mechanisms, improved muscle retention, as well as treatment of numerous clinical maladies via supplementation.
How Much Should You Take?
According to the ISSN, the best way to increase muscle creatine stores is to consume 0.3 grams per kilogram of body weight (to derive kilograms, divide weight in pounds by 2.2) for three days, followed by three to five grams per day .
As with any supplement, brand quality is key. Brands with '"fillers" are what produce side effects, like bloating, so it is worth researching a brand before buying it. Also, watch for any creatine "blends" like effervescent creatine, buffered creatine, etc. Those are marketing gimmicks. Numerous studies show there are no differences between the types. Pure creatine monohydrate is all you need.
 Buford, T. W., Kreider, R. B., Stout, J. R., Greenwood, M., Campbell, B., Spano, M., Ziegenfuss, T., Lopez, H., Landis, J., and Antiono, J. (2007). "International Society of Sports Nutrition Position Stand: Creatine Supplementation and Exercise." Journal of International Society of Sports Nutrition, 4(6).
 Hultman E, Bergstrom J, Spreit L, Soderlund K. "Energy metabolism and fatigue." In: Taylor A, Gollnick PD, Green H, editor. (1990). Biochemistry of Exercise VII. Human Kinetics. Champaign, IL, 73-92.
 Balsom PD, Soderlund K, Ekblom B. (1994). "Creatine in humans with special reference to creatine supplementation." Sports Med,18:268-80.
 Harris RC, Soderlund K, Hultman E. (1992). "Elevation of creatine in resting and exercised muscle of normal subjects by creatine supplementation." Clin Sci (London), 1992 Sep;83(3):367-74.