What is glutamine?

Glutamine is an amino acid found in high concentrations within the human body. It participates in nitrogen transport and supports the metabolism of certain immune and intestinal cells.

The body can produce glutamine, and it is also supplied by protein-containing foods such as meat, fish, dairy products, eggs and legumes.

Does glutamine increase muscle mass?

Although glutamine is an amino acid, strong evidence does not show that additional supplementation increases muscle mass or strength in healthy trainees who already consume sufficient protein.

A meta-analysis of clinical trials concluded that glutamine supplementation generally had no significant effect on aerobic performance, body composition or most immune-system outcomes in athletes.

It should therefore not be considered equivalent to whey protein, essential amino acids or creatine.

Are there situations where it may be useful?

Some studies have investigated possible effects on muscle soreness, recovery, ammonia metabolism and glycogen synthesis. Findings are of scientific interest but remain too inconsistent to support broad performance claims.

Glutamine may be more relevant in research involving very high physiological stress, prolonged exercise or exercise-related gastrointestinal strain. This does not mean that it is necessary for a typical resistance-training programme.

How does it fit into a supplement programme?

Before adding glutamine, the primary requirements should already be addressed: sufficient daily protein, energy, carbohydrates, sleep and appropriate training progression.

A glutamine supplement cannot compensate for inadequate nutrition or insufficient recovery.

Conclusion

Glutamine is physiologically important, but this does not mean that taking additional glutamine automatically enhances muscle growth. For most healthy trainees, its practical value is more limited than commonly advertised.

References

Ahmadi AR et al. The Effect of Glutamine Supplementation on Athletic Performance, Body Composition and Immune Function: A Systematic Review and Meta-Analysis. Published: 2019.

Coqueiro AY et al. Glutamine as an Anti-Fatigue Amino Acid in Sports Nutrition. Published: 2019.

Legault Z et al. The Influence of Oral L-Glutamine Supplementation on Muscle Strength Recovery and Soreness Following Eccentric Exercise. Published: 2015.