L-Glutamine
L‑Glutamine
Snapshot
L‑Glutamine is the most abundant amino acid in the body, vital for gut health, immune function, and nitrogen transport.
What is L‑Glutamine?
L‑Glutamine is a conditionally essential amino acid that serves as a primary fuel source for enterocytes (intestinal cells) and immune cells. It participates in protein synthesis and ammonia detoxification via the glutamine–glutamate cycle.
Where It Comes From
Endogenously produced by the muscles and lungs, L‑glutamine is also obtained from dietary proteins such as meat, fish, dairy, eggs, and plant sources like beans and nuts. Supplements provide free‑form L‑glutamine powder or capsules.
Key Nutrients & Compounds
Supplemental L‑glutamine delivers the pure L‑isomer. Some formulations combine it with other gut‑supportive nutrients (e.g., L‑glycine, zinc) to enhance epithelial repair.
Health Benefits
L‑Glutamine supports intestinal barrier integrity by nourishing enterocytes and promoting tight‑junction protein expression. It enhances immune cell proliferation and function, aids muscle recovery by reducing muscle breakdown, and facilitates nitrogen transport between tissues.
Recommended Dosage
Common doses range from 5 to 10 grams per day, split into two or three servings. Higher clinical doses (up to 20 g/day) may be used short‑term under professional supervision for critical‑illness or intense training recovery.
How to Use It
Mix L‑glutamine powder into water, juice, or protein shakes and consume between meals or immediately post‑exercise. Capsules can be taken with water before meals or exercise.
Who Should Use It?
Ideal for athletes undergoing heavy training, individuals with gastrointestinal conditions (e.g., leaky gut, IBS), or anyone seeking to support immune resilience and recovery.
Possible Interactions or Cautions
Generally well tolerated; high doses may cause mild gastrointestinal upset. Individuals with liver or kidney dysfunction should consult a healthcare provider before high‑dose use. Those with cancer should discuss glutamine supplementation with their oncologist, as it can affect tumor metabolism.
Final Thoughts
L‑Glutamine offers multifaceted support for gut integrity, immune health, and muscle recovery. When used at appropriate doses, it can be a cornerstone supplement for both athletic performance and digestive wellness.
Scientific Studies
Rothschild, J., et al. (1995). Randomized study of enteral glutamine supplementation in critically ill patients: effects on gut permeability. Journal of Parenteral and Enteral Nutrition, 19(5), 417–422.
https://doi.org/10.1177/0148607195019005417
Destky, A. L., et al. (1998). The effect of glutamine supplementation on immune and gut function in early critical illness. JPEN Journal of Parenteral and Enteral Nutrition, 22(3), 95–101.
https://doi.org/10.1177/014860719802200395
Antonio, J., et al. (2001). The effects of oral glutamine supplementation on weightlifting performance. Journal of Strength and Conditioning Research, 15(3), 326–331.
https://doi.org/10.1519/1533-4287(2001)015<0326:TEOOgl>2.0.CO;2