L-Glutamine: Benefits, Dosing, Where To Buy, And More!

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Key Information

Glutamine is the most abundant amino acid:

Glutamine is involved in many metabolic processes, such as protein synthesis, glutamate production, and immune function.

Glutamine may have nootropic effects:

Glutamine is a precursor of neurotransmitters like glutamate and GABA, which regulate mental activity and mood.

Glutamine supports gut health and immunity:

Glutamine reduces inflammation in the intestines, prevents leaky gut, and fuels the immune cells.

Glutamine dosage varies depending on the purpose:

Glutamine can be taken in doses of 1-5 grams for nootropic or health benefits, or more for exercise recovery.

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L-Glutamine, a conditionally essential amino acid, is vital in maintaining optimal health. As the most abundant amino acid in the body, L-Glutamine is crucial for protein synthesis, immune function, and intestinal health.

This comprehensive guide will explore the benefits, dosage, and potential side effects of L-Glutamine and its role in cognitive enhancement and overall well-being.

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How L-Glutamine Works in the Body

L-glutamine is a building block for proteins and plays a significant role in various bodily functions:

  • Protein synthesis: L-Glutamine is essential for producing proteins, which are necessary for muscle growth, repair, and maintenance.
  • Immune system support: L-glutamine is a fuel source for immune cells, helping maintain a strong and healthy immune system.
  • Intestinal health: L-Glutamine helps maintain the integrity of the intestinal lining, preventing leaky gut syndrome and supporting overall digestive health.

Learn More: How Your Gut Health Affects Your Mental Health

Benefits of L-Glutamine Supplementation

Supplementing with L-Glutamine can offer numerous benefits for both physical and mental health:

  • Muscle recovery and growth: L-Glutamine helps repair and rebuild muscle tissue after intense exercise, promoting faster recovery and muscle growth.
  • Improved immune function: L-Glutamine can help boost the body’s natural defenses against illness and infection by supporting immune cells.
  • Better gut health and digestion: L-Glutamine helps maintain the integrity of the intestinal lining, reducing inflammation and supporting healthy digestion.
  • Potential nootropic effects: L-Glutamine may have cognitive-enhancing properties, improving focus, memory, and overall brain function.

Learn More: What are Nootropics? The Ultimate Beginners Guide To Cognitive Enhancers

L-Glutamine Deficiency

While the body can produce L-Glutamine, certain factors can lead to a deficiency, including:

  • Intense exercise or physical stress
  • Injury or surgery
  • Chronic illness
  • Poor diet or malnutrition

Symptoms of L-Glutamine deficiency may include:

  • Muscle wasting
  • Fatigue
  • Impaired immune function
  • Digestive issues

L-Glutamine Dosage and Administration

The recommended daily dosage of L-Glutamine varies depending on individual needs and health status. Generally, a dosage of 5-15 grams per day, divided into smaller doses, is considered safe and effective. Factors such as age, body weight, and health conditions may influence the optimal dosage.

L-Glutamine supplements are available in various forms, including:

  • Powder
  • Capsules
  • Tablets

For optimal absorption, L-glutamine should be taken on an empty stomach, either 30 minutes before or 2 hours after a meal.

Potential Side Effects and Precautions

While L-Glutamine is generally considered safe, some individuals may experience side effects, such as:

  • Digestive discomfort (bloating, diarrhea, or constipation)
  • Headache
  • Nausea
  • Skin rash

Pregnant and breastfeeding women should consult with their healthcare provider before taking L-Glutamine supplements. Individuals with certain health conditions, such as liver or kidney disease, should also seek medical advice before supplementing with L-Glutamine.

L-Glutamine may interact with certain medications, including:

  • Anticonvulsants
  • Chemotherapy drugs
  • Lactulose

L-Glutamine and Mental Health

L-Glutamine plays a crucial role in brain function and mental health. As a precursor to the neurotransmitter glutamate, it helps regulate mood, cognitive function, and memory.

Studies have suggested that L-Glutamine supplementation may be beneficial for individuals struggling with depression, anxiety, and addiction. By supporting neurotransmitter production and reducing oxidative stress in the brain, L-Glutamine may help improve overall mental well-being.

Learn More: 13 Best Nootropics For Addiction Recovery

L-Glutamine and Gut Health

L-Glutamine is essential for maintaining a healthy gut lining, which is crucial for overall digestive health. By supporting the integrity of the intestinal barrier, L-Glutamine helps prevent leaky gut syndrome and reduces inflammation in the digestive tract.

Supplementing with L-Glutamine may be particularly beneficial for individuals with digestive disorders such as inflammatory bowel disease (IBD) or irritable bowel syndrome (IBS). Studies have shown that L-Glutamine can help reduce intestinal permeability and alleviate symptoms associated with these conditions.

L-Glutamine and Athletic Performance

Athletes and fitness enthusiasts often use L-Glutamine supplements to support muscle recovery and growth. L-Glutamine can help minimize post-exercise muscle soreness and improve overall athletic performance by reducing muscle breakdown and promoting protein synthesis.

L-Glutamine may also help improve endurance by reducing fatigue and supporting energy production during prolonged exercise. Combining L-Glutamine with other performance-enhancing supplements, such as creatine and branched-chain amino acids (BCAAs), may benefit athletes and bodybuilders.

FAQ about L-Glutamine

Glutamine SourceGlutamine Content (per 100g)
Beef1.2 g
Chicken0.9 g
Fish0.8 g
Eggs0.6 g
Dairy products0.3-0.8 g
Beans0.6-1.0 g
Spinach0.2 g
Parsley0.7 g
Glutamine content in various food sources

Where to Buy L-Glutamine

When choosing an L-Glutamine supplement, consider the following factors:

  • Quality and purity of the product
  • Reputation of the brand
  • Third-party testing and certifications (NSF, USP, GMP)
  • Form of the supplement (powder, capsules, tablets)
  • Price and value for money

L-Glutamine supplements are widely available from various sources, including:

L-Glutamine by Thorne #1

L-Glutamine by Thorne

Boost Your Brainpower

L-Glutamine Discussions on Reddit

L-Glutamine for Gut Health and IBS

I can’t speak for any of the other benefits, but I’ll note #3: Digestive Health. In my research to improve my mom’s GI health (cholecystectomy, celiac disease, chronic diarrhea, poor nutrition uptake, etc.), L-Glutamine kept popping up with a fair amount of research supporting it and it being advised by GI specialists.

u/Independent-Bug-9352 in discussion ‘Benefits Of L-Glutamine?’

L-Glutamine for Sugar Cravings and Alcohol Addiction

I’ve been using glutamine for several years. Initially, I was using it to curb sugar cravings, but after a terrible experience with food poisoning I also value using it for gut healing/health.

u/Johoski in discussion ‘L-glutamine and Cravings’

Potential Side Effects and Precautions with L-Glutamine

I have tried glutamine and it was utter trash. It exacerbated my underlying mystery disease. Irritability, brain fog, fatigue, insomnia from what I can remember. You can argue whether it was due to glutamate, ammonia, (lack of) lipopolysaccharide, or something else. One thing is for sure, I will never touch that shit again. Strange though because I find protein and protein powders completely safe.

u/FrigoCoder in discussion ‘Glutamine. Who tried it? Write your experience’


L-Glutamine is a versatile and essential amino acid crucial in supporting overall health and well-being. L-Glutamine offers a wide range of benefits for both physical and mental health by promoting muscle recovery, supporting immune function, and maintaining gut health.

As with any supplement, it is essential to consult a healthcare professional before starting an L-glutamine regimen, especially if you have pre-existing health conditions or are taking medications. While supplements can be beneficial, they should be used with a balanced diet, regular exercise, and other healthy lifestyle practices.

At Holisticnootropics.com, we aim to provide comprehensive, evidence-based information on nootropics and cognitive enhancement strategies.

We believe in a holistic mental health and well-being, recognizing the intricate connection between the mind and body. Incorporating L-Glutamine into your wellness routine can support your body’s natural healing processes and optimize your cognitive function.

We encourage you to share your experiences with L-Glutamine in the comments section below. After supplementing with L-Glutamine, have you noticed improvements in your gut health, athletic performance, or mental well-being?

Your insights and stories can help others make informed decisions about their own health journey. Remember, the key to unlocking your full potential lies in proper nutrition, regular exercise, stress management, and a positive mindset. By taking a holistic approach to your health and well-being, you can achieve optimal cognitive performance and lead a fulfilling, vibrant life.


  1. Cruzat V, Macedo Rogero M, Noel Keane K, Curi R, Newsholme P. Glutamine: Metabolism and immune function, supplementation and clinical translation. Nutrients. 2018;10(11):1564. doi: 10.3390/nu10111564. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6266414/
  2. Zhou Q, Verne ML, Fields JZ, et al. Randomised placebo-controlled trial of dietary glutamine supplements for postinfectious irritable bowel syndrome. Gut. 2019;68(6):996-1002. doi: 10.1136/gutjnl-2017-315136. https://pubmed.ncbi.nlm.nih.gov/30108163/
  3. Gleeson M. Dosing and efficacy of glutamine supplementation in human exercise and sport training. J Nutr. 2008;138(10):2045S-2049S. doi: 10.1093/jn/138.10.2045S. https://pubmed.ncbi.nlm.nih.gov/18806122/

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Erik Abramowitz is a certified Nutritional Therapy Practitioner (NTP), Naturopathic Doctoral student, health coach, and father. He is the primary content creator for HolisticNootropics.com and the host of the Holistic Nootropics Podcast.

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