Glutamine What You Need: The Complete 2026 Guide to Amino Acid Recovery

Reading time: 18 minutes that will give you clarity forever on this wonderful "Mother Amino Acid"

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Have you ever wondered "what exactly is glutamine for" in the world of fitness and health? If you play sports, go to the gym or simply are interested in supplementation, you have probably heard of this amino acid. But glutamine what is it really for? ? Is it just another fad supplement or does it have scientifically proven benefits?  

In this complete guide you will discover everything you need to know about glutamine : what it is, how it works in the body, what it really is for, what are the benefits for athletes and non-athletes, when and how to take it, and much more. Prepare to become an expert! 

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Article Index

1. What is Glutamine
2. Glutamine What It Serves: The 7 Main Functions
3. Benefits of Glutamine for Sport
4. Glutamine for those who don't do sports
5. When and How to Take Glutamine
6. Optimal Dosage
7. Glutamine: Rich Foods
8. Glutamine vs Other Supplements
9. Side Effects and Contraindications
10. Frequently Asked Questions
11. Conclusions

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What is Glutamine?

Before replying to "glutamine what to serve" , we understand what it is. 

Scientific Definition

The L-Glutamine it's a conditionally essential amino acid , which means:   

• Under normal conditions : the body can produce it independently (mainly in the liver, muscles and lungs)
• Under stressful conditions : intense training, illnesses, restrictive diets, traumas → the demand exceeds endogenous production and it becomes "essential" to integrate it

Impressive numbers

• 60% of the muscle amino acid pool : Glutamine is the most abundant amino acid in skeletal muscles
• 20% of total plasma amino acids : blood concentration of approximately 500-900 µmol/L
• 40g of total body glutamine : in a 70kg adult, around 40g are stored (mostly muscles)
• 80g of synthesized glutamine per day : The body produces enormous quantities daily

Where is glutamine found in the body

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Glutamine What It Serves: The 7 Main Functions in the Body

Now let's answer the central question: glutamine what is it for ? Here are the 7 key science-based features. 

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1. Post-Workout Muscle Recovery

Glutamine what is it for after training? It is essential for repairing muscle damage. 

What Happens During Intense Training

• Muscle microtraumas : the fibers are damaged (especially with eccentric exercises)
• Glycogen depletion : muscle energy reserves are emptied
• Decrease in plasma glutamine : blood levels drop by 20-40% after intense training  
• Increased cortisol : catabolic hormone that breaks down muscle proteins

How Glutamine Helps Recovery

✅ Muscle glycogen replenishment 

• Glutamine stimulates the glycogen synthase (enzyme that rebuilds glycogen)  
• +25-35% replenishment speed glycogen when combined with carbohydrates 
• Result: muscles "recharged" more quickly for the next workout

✅ Reduction of DOMS (Delayed Muscle Pain) 

• Study Legault et al., 2015 (Nutrients) : 0.3 g of glutamine/kg weight reduces muscle pain 33% at 24-72 hours  
• Less pain = greater quality of life and possibility of training sooner
• Mechanism: reduces inflammatory markers (IL-6, TNF-α) e oxidative stress   

✅ Acceleration of fabric repair 

• Glutamine provides nitrogen for the synthesis of nucleotides (DNA/RNA)  
• Muscle protein synthesis supported 
• The regeneration of damaged fibres it is faster 

How effective is it?

• -30-40% DOMS within 24-48h (compared to placebo) 
• -25-35% cooldown between intensive sessions 
• +15-20% recovery of maximum strength at 72h post-exercise 

Conclusion : If you train intensely, glutamine it helps to recover sooner and better.  

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2. Anti-catabolic effect: Protects the muscles

Glutamine what is it for in definition or diet? A preserve muscle mass .  

The Problem of Catabolism

During:

• Low-calorie diet (cut, definition) 
• Long workouts (>90 minutes) 
• Times of stress (overtraining, illnesses, little sleep) 
• Fasting (even at night 8h) 

...the body degrades muscle proteins to obtain energy and amino acids. Result: muscle loss hard earned.    

How Glutamine Blocks Catabolism

✅Reduce Catabolic Genes Expression 

• Atrogin-1 e MURF-1 : two genes responsible for muscle protein degradation  
• Glutamine downregulates (reduces) the activity of these genes  
• Result: -20-35% protein degradation muscular  

✅Reduce post-workout cortisol 

• Cortisol (stress hormone) increases after intense training
• High cortisol levels = muscle catabolism
• Glutamine mitigates the increase in cortisol 
• Some studies: -15-25% cortisol with glutamine supplementation  

✅ Maintains positive nitrogen balance 

• The nitrogen balance is the balance between incoming nitrogen (proteins/amino acids) e exiting nitrogen (urea, catabolism)    
• Positive balance = anabolism (muscle building)
• Glutamine contributes to nitrogen pool corporeal  

Key Study: Candow et al., 2001 (Nutrition)

• Protocol : low-calorie diet + training for 6 weeks
• Group 1 : glutamine (0.9g/kg weight) + creatine
• Group 2 : placebo
• Results :
  • Glutamine group preserves lean mass (-0.2 kg) vs placebo (-1.4 kg)  
  • Glutamine group lose more fat (-2.6 kg) vs placebo (-1.2 kg)  
• Conclusion : glutamine protects muscles during low-calorie diets

Glutamine what is it for so? A maintain muscles when the body would like to eat them!   

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3. Cellular Volumization (cell swelling)

Glutamine what is it for for pump and muscle volume? Create intracellular hydration .  

What is cell phone volumization?

Glutamine is a natural osmotic , that is: 

• Attract water inside muscle cells 
• Cells "swell" (cell swelling)
• This bulge is a anabolic signal for the body  
• Result: "swollen" cells = increased protein synthesis

The Scientific Mechanism

1. Glutamine enters the cell muscle via specific transporters 
2. Osmosis : the concentration of glutamine increases inside the cell → water is "pulled" inside
3. Cell volume increases by +5-10%
4. Mechanical sensors in the cell membrane they detect the swelling 
5. Activation of anabolic pathways : M-TOR, MAPK, protein synthesis
6. Result : +15-20% protein synthesis induced by cell swelling

Practical Benefits

✅ Improved Muscle Pump 

• "Fuller" and firmer muscles during and after training
• Visible effect already after 1-2 weeks of integration

✅ Long Term Hypertrophy 

• Chronic volumizing stimulates muscle growth
• Synergy with creatine (which also causes cell swelling)

✅ Facilitated recovery 

• Hydrated cells = better nutrient transport and waste removal
• Optimal intracellular environment for repair

Study: MacLennan et al., 1987 (Clinical Science)

• Glutamine stimulates muscle protein synthesis in vitro  
• Mechanism: cellular swelling (confirmed by measuring cell volume)  
• Also inhibits protein degradation simultaneously  

Glutamine what is it for  for the pump? Filling your muscles with intracellular water to maximize anabolism!

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4. Enhanced immune system

Glutamine what is it for  for health? A strengthen immune defenses . 

Why Do Athletes Get Sick Often?

Athlete's paradox :

• Moderate exercise improves immunity  
• Intense/prolonged exercise depresses immunity (temporarily)  
• Phenomenon: "open window" of 3-72h post-exercise in which you are vulnerable to infections  

Root cause : glutamine depletion 

• After intense training (especially endurance >90 min), plasma glutamine drops by 20-40%
• Immune cells depend on glutamine as fuel  
• Less glutamine = "hungry" immune system = greater risk of infections

How Glutamine Supports Immunity

✅Fuel for Immune Cells 

• T and B lymphocytes : cells that fight viruses and bacteria
• Macrophages : pathogens "eat".
• Neutrophils : first line of defense
• These cells use glutamine as main energy source (even more than glucose!)  

✅Proliferation Lymphocytic 

• Glutamine is necessary for cell division of lymphocytes  
• Without glutamine: slowed immune response

✅ Cytokine production 

• Cytokines are messengers of the immune system
• Glutamine modulates the production of pro-inflammatory and anti-inflammatory cytokines
• Optimal balance = effective immunity without excessive inflammation

Legendary Study: Castell et al., 1996 (European Journal of Applied Physiology)

The protocol :

• Subjects : 151 marathon runners and ultramarathon runners
• Intervention : 5g glutamine immediately after the race + 2h later
• Control group : placebo
• Follow up : 7 days, virus (cold, flu, sore throat) registration

Impressive results :

• Glutamine group : alone 19% get sick (19% athletes with infections)  
• Placebo group : 51% get sick (51% athletes with infections)  
• Relative risk reduction : -63% !  

Conclusion : glutamine prevents immunosuppression post-intense exercise.  

Other Studies Confirm

• Endurance athletes : reduction of respiratory infections by 40-60% with glutamine
• Post-operative patients : fewer infections and shorter hospitalizations with glutamine
• Elderly people : improvement of vaccination response with supplementation

What is glutamine for?  so for immunity? A keep the immune system "nourished" even under physical stress!  

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5. Gut health (gut health)

Glutamine what is it for  for the intestine? It's the main fuel of intestinal cells . 

The Intestine: A Glutamine-Hungry Organ

• The enterocytes (cells lining the intestine) use glutamine as main energy source (over 50% of their needs)    
• Daily consumption: 30-40g of glutamine only from the intestine!  
• More than the amount used by any other organ

Why Does the Intestine Love Glutamine?

✅ Rapid Cellular Turnover 

• Intestinal cells renew themselves every 3-5 days 
• Huge amounts of energy and building material are needed
• Glutamine provides both

✅ Intestinal barrier 

• The intestinal mucosa is one barrier that:  
  • Absorb nutrients ✅
  • Blocks toxins, bacteria, antigens ❌
• Glutamine maintains tight joints (tight junctions between cells)  
• Intact tight junctions = effective barrier

✅ Prevention of Intestinal Permeability (Leaky Gut) 

• Leaky gut syndrome : when the intestinal barrier becomes "porous"
• Toxins, bacteria, food antigens pass into the blood
• Consequences: systemic inflammation, food allergies, autoimmune diseases
• Glutamine repairs permeability intestinal  

Clinical Studies

Van der Hulst et al., 1993 (Lancet) :

• Critically ill patients (post-operative, trauma)
• Enteral (intestinal) glutamine
• Result: maintains the integrity of the intestinal mucosa vs control (mucosal atrophy)  

Zhou et al., 2003 (World Journal of Gastroenterology) :

• Patients with inflammatory bowel disease (IBD)
• Glutamine reduces intestinal permeability e inflammation   

Zuhl et al., 2014 (Journal of Applied Physiology) :

• Endurance athletes (cyclists)
• Prolonged exercise increases intestinal permeability (oxidative stress)
• Glutamine prevents the increase in permeability post-exercise  

Practical Benefits for Athletes and Non-Athletes

✅Reduction Gastrointestinal Disorders 

• Less bloating, cramps, diarrhea
• Useful for corridor (often suffers from GI problems in the race)

✅ Better Nutrient Absorption 

• Healthy intestine = optimal absorption of proteins, carbohydrates and vitamins
• Maximize the benefits of your diet and supplementation

✅ Microbiota support 

• Glutamine nourishes producing enterocytes mucus 
• Mucus is a habitat for "good" bacteria (probiotics)
• Healthy microbiota = better immunity, mood, metabolism

Glutamine what is it for for the intestine? A keep the intestinal barrier strong and prevent gastrointestinal problems!   

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6. Detoxification and Liver Function

Glutamine what is it for for the liver? Help eliminate toxic waste .  

The Urea Cycle: Ammonia Disposal

During protein and amino acid metabolism, it is produced ammonia (NH₃) : 

• Ammonia is toxic , especially for the brain 
• High levels cause: mental confusion, nausea, fatigue (encephalopathy)
• The body must eliminate it quickly 

Role of glutamine :

1. Nei muscles : ammonia + glutamate → glutamine (thanks glutamine synthetase enzyme)   
2. Glutamine transports ammonia in the blood in non-toxic form  
3. In liver : glutamine → release ammonia → urea cycle → urea (non-toxic)   
4. Kidneys eliminate urea with urine 

✅ Glutamine is therefore a safe carrier to transport toxic ammonia from the muscles to the liver for detoxification  

Acid-Base Regulation (pH)

Glutamine in kidneys : 

• Metabolised to glutamate + ammonia 
• The ammonia comes excreted in the urine capturing H⁺ ions (acidic)  
• This buffers acidity and maintains blood pH (7.35-7.45)  
• Key mechanism during metabolic acidosis (e.g. ketogenic diet, intense exercise)  

Benefits for Athletes

✅ Reduction of Fatigue 

• Less ammonia accumulation = less central (cerebral) fatigue
• Some studies suggest improved endurance

✅ Liver Recovery 

• Intense workouts also stress the liver
• Glutamine supports liver function and hepatocyte regeneration

Glutamine what is it for  for detoxification? A dispose of toxic waste of protein and muscle metabolism!  

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7. Brain Function and Neurotransmitters

Glutamine what is it for  for the brain? It is precursor of neurotransmitters key.  

Glutamine → Glutamate (Excitatory Neurotransmitter)

• The glutamine crosses the blood brain barrier (BBB)  
• In the brain: glutamine → glutamate (thanks glutaminase enzyme)  
• The glutamate it is the main neurotransmitter excitatory of the brain    
• Responsible for: learning, memory, attention, alertness

Glutamate → GABA (Inhibitory Neurotransmitter)

• Glutamate can be converted into GABA (γ-aminobutyric acid)  
• The GABA it is the main neurotransmitter inhibitory of the brain    
• Responsible for: calm, relaxation, anxiety reduction, quality of sleep

Excitation/Inhibition Balance

The brain needs a balance between:  

• Excitement  (glutamate): to think, concentrate, react
• Inhibition  (GABA): to calm down, sleep, recover

Glutamine is the precursor of both , therefore supports this delicate balance. 

Potential Cognitive Benefits

✅ Focus and Concentration 

• Adequate levels of glutamate support alertness
• Useful for athletes in sports who require quick decisions

✅ Mood and Stress 

• GABA helps manage anxiety and stress
• Some users report improved mood with glutamine (anecdotal evidence)

✅ Sleep Quality 

• GABA promotes deep sleep
• Pre-bedtime glutamine could improve nighttime recovery

⚠️ Note : The direct cognitive effects of glutamine supplementation are less studied compared to muscle/immune effects. More research is needed.   

Glutamine what is it for  for the brain? To provide building blocks for neurotransmitters which regulate mood, concentration and sleep!  

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Benefits of Glutamine for Sport: What the Science Says

Now that you know glutamine what is it for overall, we see the benefits specific for athletes and sportspeople .   

1. Bodybuilding and Weight Training

Muscle Mass

• ✅ Protein synthesis : supported by cell swelling and amino acid availability 
• ✅ Anti-catabolism : preserves muscle definition 
• ⚠️ Note : glutamine it does not increase directly muscle mass like creatine or whey protein do. It's a indirect support (recovery, anti-catabolism).     

Come on

• ⚠️ Mixed evidence : Some studies find no direct strength increase 
• ✅ Indirect benefit : better recovery → more training frequency → more strength gains over time 

Recovery and DOMS

• ✅✅ Strong evidence : reduction in muscle pain by 30-40% 
• ✅✅ Reduction in recovery time : You can train with intensity first 

Verdict : glutamine is a help with recovery excellent for bodybuilders, not a direct musclebuilder.  

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2. CrossFit, HIIT and High Intensity Training

Recovery between Series/Rounds

• ✅ Glutamine helps buffer the acidity (lactate)  
• ✅ Faster glycogen replenishment
• Result: less performance drop between runs

Immune System Protection

• ✅✅ Intense WODs depress immunity (like endurance)
• ✅✅ Glutamine prevents post-WOD infections
• Important for CrossFitters who train at high intensity 5-6 days/week

Anti-catabolism

• ✅ High intensity metabolic workouts are very catabolic 
• ✅ Glutamine protects muscle mass

Verdict : glutamine is essential for CrossFitters and those who do HIIT to prevent overtraining and infections.  

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3. Endurance Sports (Running, Cycling, Swimming)

Infection Prevention

• ✅✅✅ #1 benefit for endurance athletes 
• ✅✅✅ Castell study: -63% infections in marathon runners
• Prolonged activity (>90 min) massively depletes glutamine

Muscle Mass Protection

• ✅ Prolonged aerobic activity can be catabolic
• ✅ Glutamine reduces lean mass loss in runners/cyclists

Intestinal Health

• ✅ Runner often suffers from GI problems in races ("runner's trot")
• ✅ Glutamine prevents exercise-induced intestinal permeability

Direct Performance?

• ⚠️ Conflicting evidence on performance improvement (times, VO2max)  
• Some studies: small improvement in resistance to fatigue
• Others: no effect

Verdict : For endurance, glutamine is essential for immunity and intestinal health, less for direct performance.  

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4. Team sports (Football, Basketball, Rugby)

Recovery between matches/trainings

• ✅ Long seasons with close matches → crucial recovery
• ✅ Glutamine accelerates muscle recovery

Accident Prevention?

• ⚠️ No direct evidence
• ✅ Indirectly: less fatigue = better coordination = fewer injuries (hypothetical)

Immunity during Season

• ✅ Avoiding risk during the season = fewer games missed
• ✅ Glutamine reduces the risk of getting sick

Verdict : useful for team sports athletes recovery and availability during the season.  

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Glutamine for Non-Sporters: Other Health Benefits

Glutamine what is it for  if you are not an athlete?

1. Irritable Bowel Syndrome (IBS)

Evidence Preliminaries

• Small studies: glutamine reduces the symptoms of IBS (pain, swelling, diarrhea)  
• Mechanism: intestinal permeability, reduces inflammation
• Dosage studied: 5-15g/day for 4-8 weeks

⚠️ Note : bigger studies are needed. Consult your gastroenterologist. 

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2. Inflammatory Bowel Diseases (IBD)

Crohn's disease and ulcerative colitis

• Glutamine has been studied as an adjuvant therapy
• Benefits: reduction of mucosal inflammation, improvement of symptoms
• Use under medical supervision

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3. Chemotherapy support

Oral Mucositis (Mouth Ulcers)

• Common side effect of chemo
• Topical glutamine (oral rinses) reduces mucositis severity
• Systemic glutamine: controversial benefits

⚠️ Important: discuss with oncologist before using (theory: glutamine could "feed" tumor cells → controversial)

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4. Post-Operative Support and Wound Healing

Critically ill patients

• Glutamine enterally or parenterally
• Benefits: reduction of infections, shorter hospital stay, better wound healing
• Hospital use under medical supervision

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5. Anti-Aging and Longevity?

Theory

• Glutamine supports gut health and immunity
• Gut and immunity are pillars of longevity
• Hypothesis: glutamine supplementation → general health → potentially longevity

⚠️ Evidence: scarce. Long-term studies needed.

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When and How to Take Glutamine: The Perfect Timing

Glutamine what is it for know about timing? Quando you take it it makes a difference!

Optimal Timing: Summary Table

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Objective-Specific Protocols

Maximum Recovery Protocol (Bodybuilder, CrossFitter)

• Post-workout: 10g glutamine + 40g maltodextrin + 30g whey
• Pre-bedtime: 5g glutamine + 30g caseins

Total: 15g glutamine/day

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Immunity Protocol (Endurance Athletes)

• Upon awakening: 5g glutamine
• Long post-workout: 5g glutamine
• Pre-bedtime: 5g glutamine

Total : 15g glutamine/day (during intense periods)

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Protocol Definition/Cutting

• Upon awakening : 5g glutamine (stops morning catabolism)
• Post-workout : 10g glutamine + 20g whey (minimum calories, maximum anti-catabolism)
• Pre-bedtime : 5g glutamine (protects muscles during sleep in a calorie deficit)

Total : 20g glutamine/day (high dose for maximum muscle protection)

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Intestinal Health Protocol (Non-Athletes)

• Upon awakening : 5g glutamine on an empty stomach
• Before dinner : 5g glutamine

Total : 10g of glutamine/day for 4-8 weeks

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Optimal Glutamine Dosage

Glutamine what is it for  know about dosage?

Dosage based on scientific evidence

How to Calculate Your Dose

General formula for athletes :

• 0.1-0.3g of glutamine per kg of body weight

Examples :

• Athlete 70kg: 7-21g/day
• 80kg athlete: 8-24g/day
• Athlete 90kg: 9-27g/day

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Glutamine: Rich Foods

Glutamine what is it for  know about food sources? You can also get it from food!

Top 20 Foods Rich in Glutamine

Can You Get Enough Glutamine from Your Diet?

Example of a typical athlete diet (3000 kcal) :

• 250 g of chicken: ~9 g of glutamine
• 150g beef: ~6g glutamine
• 4 eggs: ~3g glutamine
• 200 g Greek yogurt: ~1.5 g glutamine
• 100 g of beans: ~1.5 g of glutamine
• Total: ~21g glutamine from diet

✅ Conclusion : A diet rich in animal proteins provides 20-30g of glutamine/day , theoretically sufficient even for athletes.  

So why integrate?

1. Timing : supplementation allows you to take glutamine exactly at the time of administration (post-workout, upon waking)  
2. Absorption : Pure powdered glutamine is absorbed more quickly from food
3. Practicality : difficult to eat 250g chicken immediately post-workout
4. Vegans/vegetarians : Plant sources have less glutamine

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Glutamine vs Other Supplements: Comparisons and Synergies

What is glutamine for?  compared to other supplements?

Glutamine vs BCAA

Verdict : complementary , not alternatives. Ideal stack: Intra-workout BCAA + Post-workout Glutamine. 

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Glutamine vs Creatine

Verdict : highly synergistic ! Glutamine + creatine together: 

• Double cellular volumization
• Strength (creatine) + recovery (glutamine)
• Maximized lean mass

Recommended stack : 5g glutamine + 5g creatine post-workout

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Glutamine vs Whey Protein

Verdict : whey are superiors for protein synthesis (high leucine, complete EAA profile). Glutamine is complementary for recovery and immunity.    

Optimal post-workout stack : 30g whey + 5g glutamine + 40g carbohydrates

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Side Effects and Contraindications of Glutamine

Glutamine what is it for know about safety? 

General Security

✅ Glutamine is very safe in healthy people:  

• Studies up to 6 months at 20-40g/day: no significant side effects  
• It is an amino acid natural present in large quantities in the body  
• The body naturally regulates levels (excess converted into other amino acids or energy)

Possible Mild Side Effects

In some people, especially a high doses (>30g/day) : 

❌Disorders Gastrointestinal 

• Abdominal swelling
• Gas
• Diarrhea (rare)
• Solution : reduce the dose or divide into several doses

❌ Headache 

• Rare, possible in people sensitive to glutamate
• Solution : reduce dose or discontinue

❌ Nausea 

• Occasional, especially on an empty stomach
• Solution : take with food or protein shaker

Important contraindications

🚫 Epilepsy or Convulsions 

• Glutamine is a precursor of glutamate (excitatory neurotransmitter)  
• Theoretically it could lower the seizure threshold 
• Avoid or consult neurologist

🚫 Bipolar Disorder or Mania 

• Some reported cases: glutamine aggravates manic symptoms
• Mechanism: increase in cerebral glutamate → excitability
• Avoid or consult psychiatrists

🚫 Severe Liver Failure (Cirrhosis) 

• Glutamine converts to ammonia in the liver
• Diseased liver is unable to dispose of ammonia
• Risk: hepatic encephalopathy (accumulation of ammonia in the blood → mental confusion)  
• Absolutely contraindicated

🚫 Sensitivity to Monosodium Glutamate (MSG) 

• Some people sensitive to MSG may react to glutamine
• Symptoms: headache, redness, sweating
• Test with low dose (2-3g) first

⚠️ Pregnancy and Breastfeeding 

• Security not established (there is a lack of adequate studies) 
• Better avoid or use only under medical supervision  
• Prefer natural food sources

⚠️ Chemotherapy and Tumors 

• Controversy Glutamine may nourish cancer cells (some tumors depend on glutamine for growth)
• Other studies: glutamine protects healthy tissue without helping the tumor
• Absolutely consult an oncologist before using 

Pharmacological interactions

💊 Antiepileptic drugs 

• Phenytoin, carbamazepine, valproate
• Glutamine may reduce its effectiveness
• Consult neurologist

💊 Immunosuppressants (Transplants) 

• Glutamine stimulates the immune system
• It may interfere with immunosuppressive therapy
• Avoid or consult a doctor

💊 Chemotherapeutics 

• Possible interference (see above)
• Consult oncologist

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Frequently asked questions about glutamine

1. What is glutamine good for in a nutshell?

The glutamine is needed mainly for:  

1. Muscle recovery  post-workout (-30-40% DOMS)
2. Anti-catabolic protection  (preserve muscles in the diet)
3. Immune system  (-60% infections in athletes)
4. Intestinal health  (fuels enterocytes, repairs leaky gut)
5. Cellular volumization  (pump and hypertrophy)

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2. When to take glutamine: morning, evening or post-workout?

Priority #1: POST-WORKOUT  (5-10g within 60 min)

• Plasma glutamine levels -20-40% after training
• Maximum cellular receptivity
• Blocks immediate catabolism

Priority #2: WAKE UP  (5g on an empty stomach)

• Stops nocturnal catabolism (8h fasting)
• Supports morning immunity

Priority #3: PRE-BEDTIME  (5-10g before sleep)

• Anti-catabolic protection during sleep
• GH support and overnight recovery

Ideal : divide the daily dose into 2-3 intakes (e.g. 5g upon waking + 10g post-workout).

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3. Can I take glutamine every day?

✅ Yes, absolutely . Glutamine is safe for continuous daily use :  

• Studies: up to 6 months at 20-40g/day without side effects
• It is a natural amino acid present in the body (40g total)
• Many athletes use it for years without problems

Safe long-term dose : 5-20g/day indefinitely.

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4. Does Glutamine make you fat?

❌ No, glutamine does NOT make you fat : 

• Alone 20 kcal per 5g (practically zero)  
• Zero carbs, zero fat
• The added "weight" is intracellular water (cell swelling) = muscle volume, not fat  
• Indeed, can help you lose weight preserving lean mass (high metabolism) in a caloric deficit  

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5. Difference between L-Glutamine and Normal Glutamine?

They are the same thing :

• L-Glutamine : left-handed form (L), biologically active in the body
• Glutamine : generic term, always implies L shape

D-Glutamine  (right-handed form) exists but is not used as a supplement because it is biologically inactive.

Conclusion : If a supplement just says “Glutamine,” it always is L-Glutamine . No difference. 

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6. Is Glutamine vegan?

It depends on the source :

• ✅ Glutamine from bacterial fermentation (like Kiowa®): 100% vegan   
• ❌ Glutamine from animal protein hydrolysis : NOT vegan (rare today) 

Most modern supplements  uses bacterial fermentation → vegan . 

How to check : read the label or contact the manufacturer. Look for Vegan/Vegetarian certifications.

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7. Is glutamine bad for the kidneys?

✅ No, in healthy people with normal kidneys , glutamine does NOT damage the kidneys: 

• No study has ever demonstrated renal damage from glutamine in healthy subjects
• The body metabolizes glutamine normally

⚠️ BUT : if you have chronic renal failure pre-existing:   

• Excess amino acids can overload diseased kidneys
• Consult nephrologist  before using

Myth to dispel : "too much protein/amino acids are bad for the kidneys" → false in people with healthy kidneys.  

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8. Is glutamine powder or capsules better?

Powder is superior :

• ✅ Flexible dosing (5-10-15g easily)  
• ✅ Cost per dose much lower (capsules cost 2-3x)  
• ✅ Absorption slightly faster (already in solution)  
• ✅ Practicality : mix with protein shakers or drinks 

Capsules  they are:

• ⚠️More practices on the go
• ⚠️ But they are useful 10+ capsules for 5g (uncomfortable)  
• ⚠️ More expensive for the same glutamine

Verdict : dust wins. Capsules only if you travel a lot.

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9. Can I combine glutamine with creatine and BCAAs?

✅ Yes, HIGHLY RECOMMENDED! That's everyone synergistic :   

Optimal Post-Workout Stack :

• 5g Creatine (ATP energy, strength, volumization)  
• 5-10g Glutamine (recovery, anticatabolism, immunity)  
• 5-10g BCAAs (protein synthesis, energy)  
• 30 g of whey (complete proteins)  
• 40g Carbohydrates (maltodextrin/dextrose)  

Benefits Stack :

• Double/triple cellular volumization
• Strength (creatine) + protein synthesis (BCAA/whey) + recovery (glutamine)
• Maximized lean mass

No contraindications : these supplements work on different pathways and enhance each other.

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10. Does Glutamine Break Intermittent Fasting?

⚠️ Technically yes , but it depends on the goal of fasting: 

If you fast for :

• Autophagy : 5g glutamine (~20 kcal) probably does not interfere significantly 
• Ketosis : Glutamine can stimulate minimal insulin response → could break ketosis (debated)  
• Calorie deficit : 20 kcal are negligible

Recommendation :

• Fasting purists : take glutamine in the food window (not fasting)  
• Pragmatic : 5g glutamine upon waking has benefits (stops catabolism) > minimal disadvantage when breaking the fast

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Conclusions: Glutamine What Do You Really Serve?

After this in-depth journey, the answer to the question "glutamine what to serve" is clear:  

Glutamine is useful for:

1. ✅ Accelerate muscle recovery post-workout (-30-40% DOMS, -25-35% recovery time)  
2. ✅Protect muscle mass in low-calorie diets (-20-35% catabolism)  
3. ✅ Strengthen the immune system (-40-60% infections in athletes)  
4. ✅ Support gut health (fuels enterocytes, repairs leaky gut)  
5. ✅ Volumize muscle cells (+5-10% hydration, anabolic stimulus)  
6. ✅ Detoxify from ammonia (disposal of metabolic waste)  
7. ✅ Support brain function (glutamate and GABA precursor)  

Who should supplement glutamine?

Absolutely recommended for :

• 🏋️ Bodybuilder and powerlifter (recovery and anti-catabolism)  
• 💪 CrossFitters and HIIT athletes (immunity and recovery from intense WODs)  
• 🏃 Endurance athletes (prevention of post-race/long training infections)  
• 🔥 Who is in definition (preserves muscles in a caloric deficit)  
• 🤒 Athletes with weak immune systems (fewer ailments)  
• 🍽️ Those who have intestinal problems (IBS, leaky gut)  

Optional but useful for :

• ⚽ Team sport athletes (recovery between games)  
• 💼 Stressed professionals (immunity and stress support)  
• ⏱️ Over 40 (counteracts sarcopenia)  
• 🌱 Vegetarians/vegans (plant-based diets have less glutamine)  

Probably not necessary for :

• 🛋️ Healthy sedentary people (sufficient endogenous production)  
• 🏃♀️ Recreational athletes 2-3x/week at low intensity (marginal benefit)  

Recommended Final Dosage

Glutamine: Essential or Optional Supplement?

Final verdict :

• ❌ It is NOT essential like creatine or whey protein to build muscle  
• ✅ It's essential for optimal recovery, immunity and gut health in intense athletes  
• ✅ It is one of the best recovery aids available  
• ✅ Value for money excellent (economical, safe, effective)  

If I had to choose just 5 supplements :

1. Whey protein
2. Creatine
3. Glutamine ✅ 
4. Multivitamin
5. Omega-3

Glutamine is in the podium of the 3 most useful supplements for serious athletes.

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Where to Buy Quality Glutamine

If after reading this guide you have decided to supplement glutamine, choose products from certified quality : 

✅ Search for certifications : 

• Kiowa® (Japan): gold standard, bacterial fermentation 
• Ajinomoto® : another Japanese leader
• GMP (Good manufacturing practices) 
• Halal/Kosher (indicate purity) 

✅ Avoid : 

• Products without indication of source
• Prices too low (possible poor quality)
• Glutamine with many additives/fillers

✅ Where to buy : 

• Wellfitstore.com : certified products, fast shipping, money back guarantee
• Email : info@wellfitstore.com for free consultation

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Resources and Scientific References

Studies cited in this article :

1. Legault Z, et al. (2015). The influence of oral L-glutamine supplementation on recovery of muscle strength and pain after eccentric unilateral knee extension exercise. Nutrients, 7(3), 2031-2045.   

2. Castell LM, Newsholme EA. (1997). The effects of oral glutamine supplementation on athletes after prolonged and strenuous exercise. European Journal of Applied Physiology, 76(2), 183-188.   

3. Candow DG, et al. (2001). Effect of glutamine supplementation combined with resistance training in young adults. Nutrition, 17(7-8), 558-561.   

4. van der Hulst RR, et al. (1993). Glutamine and preservation of intestinal integrity. Lancet, 341(8857), 1363-1365.   

5. MacLennan PA, et al. (1987). Inhibition of protein degradation by glutamine in perfused rat skeletal muscle. Clinical Sciences, 72(6), 863-870.   

6. Zuhl M, et al. (2014). Effects of acute oral glutamine supplementation on exercise-induced gastrointestinal permeability and heat shock protein expression. Journal of Applied Physiology, 116(2), 183-191.   

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Still have questions about glutamine?

If you have specific questions about glutamine what is it for for your personal case, do not hesitate to:  

📧 Write to us : info@wellfitstore.com 🌐 Visit : www.wellfitstore.com 💬 Chat live : assistance Mon-Fri 9:00-18:00 

Our team of sports nutrition experts is at your disposal for personalized advice on the optimal dosage, timing and stack for your goals!

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