L-Glutamine
L-Glutamine
The most abundant amino acid in the body, supporting gut health, immune function, and muscle recovery.
L-Glutamine is a conditionally essential amino acid that becomes crucial during stress, illness, or intense training. It's the primary fuel source for intestinal cells and immune cells. Supplementation is most beneficial during periods of high physical stress, gut issues, or immune challenges. Healthy individuals on adequate protein may not need it.
Mechanisms of Action
Intestinal Fuel
Primary energy source for gut cells
Immune Cell Support
Fuels rapidly dividing immune cells
Nitrogen Transport
Carries nitrogen between tissues
Recommended Dose
5-10g
Optimal Timing
- Post-workout
- Before bed
- Or split throughout day
Can be taken without food
Best Form
L-Glutamine powder
Alternatives: Capsules (but need many for effective dose)
Powder is most practical due to large doses needed. Tasteless and mixes easily.
Duration
Minimum: 2 weeks
Optimal: 4 weeks
Cycling: Not required
Note: Can be taken with or without food. For gut health, some prefer taking on empty stomach. Split doses may be easier on digestion.
Improved Gut Health
Supports intestinal lining integrity
Immune Support
May reduce infection risk during heavy training
Enhanced Recovery
May reduce soreness after intense exercise
Likely safe at moderate doses; consult doctor
Consult oncologist; glutamine feeding of tumors is debated
Who Should NOT Take This
- Liver disease (impaired glutamine metabolism)
- Reye's syndrome
- Sensitivity to MSG (glutamine converts to glutamate)
Drug Interactions
May reduce lactulose effectiveness
May affect seizure control in some
Possible Side Effects
Tip: Start with lower dose
Tip: Split doses throughout day
Warnings
- Benefits may be minimal if already consuming adequate protein
- Most beneficial during illness, stress, or intense training
Stehle P et al. • Critical Care Medicine (2020)
“Parenteral glutamine supplementation reduced infectious complications and hospital length of stay in ICU patients.”
Key Findings:
- Parenteral glutamine reduced infectious complications in ICU patients
- Significant reduction in hospital length of stay
- Enteral glutamine showed less consistent benefits than parenteral
Ramezani Ahmadi A et al. • Nutrients (2019)
“Glutamine supplementation attenuated exercise-induced immune suppression markers including reduced upper respiratory tract infections in athletes.”
Key Findings:
- Reduced incidence of upper respiratory tract infections post-exercise
- Maintained lymphocyte proliferation capacity after intense exercise
- Optimal dosing of 0.3 g/kg body weight for immune support
Rao R, Samak G • Annals of the New York Academy of Sciences (2012)
“Glutamine supplementation protects the gut barrier during stress.”
Key Findings:
- Supports tight junction proteins
- Reduces intestinal permeability
- Beneficial during gut stress
Gleeson M • Journal of Nutrition (2008)
“Glutamine supplementation may benefit immune function during heavy training.”
Key Findings:
- May reduce infection risk in athletes
- Benefits most clear during intense training
- Supports gut health during exercise
Calder PC, Yaqoob P • Amino Acids (1999)
“Glutamine is essential for optimal immune cell function.”
Key Findings:
- Critical fuel for immune cells
- Levels drop during stress and illness
- Supplementation may support immunity
AI-discovered studies. Verify citations before citing.
L-glutamine supplementation in critically ill patients: A systematic review and meta-analysis
DOIStehle P et al. • Critical Care Medicine (2020)
Parenteral glutamine supplementation reduced infectious complications and hospital length of stay in ICU patients.
- Parenteral glutamine reduced infectious complications in ICU patients
- Significant reduction in hospital length of stay
- Enteral glutamine showed less consistent benefits than parenteral
Effects of glutamine supplementation on exercise-induced immune suppression: A systematic review and meta-analysis
DOIRamezani Ahmadi A et al. • Nutrients (2019)
Glutamine supplementation attenuated exercise-induced immune suppression markers including reduced upper respiratory tract infections in athletes.
- Reduced incidence of upper respiratory tract infections post-exercise
- Maintained lymphocyte proliferation capacity after intense exercise
- Optimal dosing of 0.3 g/kg body weight for immune support
Glutamine and intestinal barrier function
Rao R, Samak G • Annals of the New York Academy of Sciences (2012)
Glutamine supplementation protects the gut barrier during stress.
- Supports tight junction proteins
- Reduces intestinal permeability
- Beneficial during gut stress