Creatine, glutamine and protein are commonly included in sports performance supplements. Each serves a distinct purpose. Creatine provides your muscles with energy and draws in water needed for growth and recovery. Glutamine is an amino acid, the building block of protein, that is most abundant in muscles. Protein is needed to fuel muscle growth and recovery following exercise.
The shortening of proteins drives the contractions of your muscles. Your muscles need to add new contractile proteins to repair exercise-induced damage and increase muscle strength and endurance. Muscle proteins that are damaged during exercise require dietary protein to repair. Dietary protein is also required for new contractile proteins to be added in order to increase muscle strength. According to a 1995 study in the "International Journal of Sports Nutrition," athletes require 1.2 to 1.8 grams of protein per kilogram of bodyweight per day to keep up with the demands of intense exercise.
Glutamine is the most abundant amino acid in your muscles, needing replacement after exercise. Although your body can normally produce glutamine on its own, your body may not be able to produce enough glutamine to keep up with the demands of intense exercise. Even though your total protein intake may be adequate to meet exercise demands, adding extra glutamine in your diet can help aid muscle recovery. According to the University of Maryland Medical Center, not having enough glutamine after intense exercise may lead to decreased immune system function.
Creatine is a chemical your body produces from amino acids. Creatine serves as a quick source of energy for your muscles but is exhausted by a few seconds of intense exercise. Increasing the level of creatine in your muscles can increase strength and exercise capacity, although it is unclear whether creatine supplements can increase muscle creatine levels beyond innate limits, according to the University of Maryland Medical Center. People who have an impaired metabolism or circulation have been shown to benefit from creatine supplements, as their bodies cannot produce enough creatine. Taking creatine during exercise may help replenish depleted creatine stores more quickly after exercise, although further research is needed.
No known significant health effects have been shown in athletes taking supplements containing protein, glutamine or creatine. These supplements may increase your body's need for water, especially during intense exercise or in hot environments. Exercise supplements should be used as a small part of a balanced and healthy diet. Consult with your doctor before using sports supplements if you are currently under medical care, especially for heart or kidney problems.