By Bill Willis, BSc, a PhD candidate at The Ohio State University.
Glutamine is known as a “conditionally essential” amino acid. Glutamine becomes “essential” during intense stresses to the body, such as during illness, trauma, or intense exercise where the need for glutamine is greatly increased.
The primary source for extra glutamine when it is needed is muscle tissue. During intense weight training and cardio, muscle protein is broken down into amino acids such as glutamine, which enters the bloodstream and travels into the liver where it is converted into glucose; this newly synthesized glucose helps to fuel the working muscles. This process is known as gluconeogenesis - the process of turning a non-carbohydrate substance (glutamine and some other amino acids) into glucose which can be used for energy.
During an intense workout, the body rapidly degrades muscle tissue to obtain glutamine; preventing this process would have a huge effect on muscle growth. If less muscle tissue is broken down during the workout we will recover much faster and ultimately see increases in muscle mass and strength more quickly. Supplying the muscles with an exogenous source of glutamine (i.e. a glutamine supplement) has been shown to reduce muscle degradation during intense weight training exercise-the body is “tricked” into not breaking down as much muscle tissue because the need for additional glutamine is satisfied.
However, glutamine has a subtle effect. Over time you will recover more quickly from intense weight training workouts, resulting in faster and further progress above guys using a supplement regimen not including glutamine. It is often reported by those using a glutamine supplement that they have much less muscle soreness in the days following an intense weight training workout, supporting the notion that glutamine inhibits muscle tissue breakdown.
Glutamine is best taken immediately before and after an intense weight training workout, in doses of 5-10 grams depending on body weight. Taking glutamine consistently over time will result in greater increases in muscle mass, especially during catabolic conditions such as cutting up on a low calorie diet.