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L-Glutamic Acid

Non-essential amino acid crucial for brain function, neurotransmitter synthesis, and immune system support

Scientific nameL-Glutamic Acid FormulaC5H9NO4 Molecular weight147.13 g/mol CAS56-86-0
95 absorption score
7 safety / 10
18 USD per month
5 documented interactions

Check it against something

Evidence level A

L-Glutamic Acid with:

Compatibility score 82 out of 100
82 out of 100
Works better together Compatible. Timing differs, so follow each supplement's own window.

Check it against your whole stack →

What it does

mechanism and evidence for each claim

Enhanced brain function and cognitive performance

Primary excitatory neurotransmitter supporting learning and memory

Main excitatory neurotransmitter in central nervous system Evidence A-grade 2-4 weeks

Improved immune system function

Critical fuel source for immune cells and antibody production

Primary energy substrate for lymphocytes and immune cells Evidence A-grade 2-6 weeks

Enhanced protein synthesis and muscle health

Important for protein metabolism and muscle tissue maintenance

Essential amino acid for protein synthesis and nitrogen metabolism Evidence A-grade 2-8 weeks

Digestive health and gut barrier function

Primary fuel source for intestinal cells and gut health

Major energy substrate for enterocytes and gut barrier integrity Evidence A-grade 1-4 weeks

Detoxification and ammonia removal

Critical for ammonia detoxification and nitrogen metabolism

Converts ammonia to glutamine for safe nitrogen transport Evidence A-grade 1-3 weeks

Others take these for the same thing

Same goal, different mechanism — check any of them against this one

Probiotics for Autoimmune Disease Support Gut health & immune modulation 10-100 billion CFU daily B 60% Vitamin B12 (Cyanocobalamin) Energy & nerve support 250-1000 mcg A 70% Vitamin D3 Bone health & immune support 1000-2000 IU A 85% Fish Oil (EPA/DHA) Heart & brain health 1-2g EPA/DHA A 85% L-Theanine Calm focus & stress relief 100-400mg B 90% Vitamin B8 (Inositol) Mental health & PCOS support 2-18g (condition dependent) B 95%

Every pair we checked

12 combinations scored by the engine
L-Glutamic Acid + Caffeine No documented interaction either way No known interaction 70
L-Glutamic Acid + Creatine Monohydrate No documented interaction either way No known interaction 70
L-Glutamic Acid + Calcium Carbonate No documented interaction either way No known interaction 70
L-Glutamic Acid + Whey Protein No documented interaction either way No known interaction 70
L-Glutamic Acid + Lactase No documented interaction either way No known interaction 70
L-Glutamic Acid + Bovine Collagen No documented interaction either way No known interaction 70
L-Glutamic Acid + DHA No documented interaction either way No known interaction 70
L-Glutamic Acid + Turmeric No documented interaction either way No known interaction 70
L-Glutamic Acid + Fish Oil (EPA/DHA) No documented interaction either way No known interaction 70
L-Glutamic Acid + L-Glutamine Glutamine converts to glutamic acid as needed Works better together 82
L-Glutamic Acid + Vitamin D3 B vitamins essential for amino acid metabolism and neurotransmitter function Works better together 82
L-Glutamic Acid + Magnesium Oxide Magnesium modulates glutamate receptor function Works better together 82

Dosage

With meals avoid evening
Daily2-6g
Maintenance1-3g daily
Therapeutic3-6g daily
Cognitive enhancement2-5g daily
Maximum10g daily (divided doses)

Before you take it

VeganYes

When to expect it

First Effects1-2 weeks for cognitive and immune benefits
Peak Benefits4-8 weeks for sustained brain and immune support
Deficiency DevelopmentRare due to body synthesis and dietary sources
Toxicity OnsetPossible with very high doses, mainly nervous system effects

How to measure it

$80-150
MarkerPlasma glutamic acid levels or neurotransmitter panels
Optimal50-150 μmol/L
Deficient below<30 μmol/L
FrequencyOnly if monitoring cognitive function or immune health

What actually reaches you

The label counts the carrier, your body does not
Absorption Very high 95 of 100 · best absorbed form of this compound
Delivered daily 3800 mg
Cost per 100 mg delivered $0.02 comparative — uses the absorption score, not a measured percentage

Works better with

3 documented
+
Glutamine

Glutamine converts to glutamic acid as needed

Direct metabolic conversion and complementary functions · level A
+
B Vitamins

B vitamins essential for amino acid metabolism and neurotransmitter function

Cofactors for neurotransmitter synthesis and metabolism · level A
+
Magnesium

Magnesium modulates glutamate receptor function

Natural NMDA receptor antagonist balancing glutamate effects · level A

What not to take with L-Glutamic Acid

2 documented
!
Excessive Gaba

GABA is inhibitory neurotransmitter opposing glutamate

Balance between excitatory and inhibitory neurotransmission · moderate significance
!
Alcohol

Alcohol disrupts glutamate-GABA balance

Alters excitatory-inhibitory neurotransmitter balance · moderate significance

Medication interactions

Discuss these with a pharmacist before combining
anticonvulsants Moderate

May interact with seizure medications

What to do: Medical supervision recommended

psychiatric-medications Minor

May affect neurotransmitter balance

What to do: Monitor for mood or cognitive changes

Available forms

bioavailability compared
L-Glutamic Acid (Free Form) 95

L-Glutamic Acid (Free Form): Brain function, Immune support, Gut health, Well-researched

Food sources

before you supplement
Parmesan cheese 1.2-1.5g per 100g · 85
Tomatoes 0.2-0.3g per 100g · 90
Mushrooms 0.1-0.2g per 100g · 90
Fish 1.5-2.0g per 100g · 95
Meat 1.2-1.8g per 100g · 95

Too little

deficiency signs
  • Rare due to body synthesis:
  • Poor cognitive function
  • Impaired immune response
  • Digestive and gut problems
  • Reduced protein synthesis
  • Poor detoxification capacity
  • Memory and learning difficulties

Too much

toxicity signs
  • Moderate safety profile:
  • Headaches and nervous system overstimulation
  • Digestive upset with large doses
  • MSG-like sensitivity reactions
  • Potential excitotoxicity with excessive intake

Who benefits most

cognitive-enhancement-students

Primary neurotransmitter for learning, memory, and brain function

2-5g daily
immune-system-support

Critical fuel source for immune cells and antibody production

3-6g daily
digestive-gut-health

Primary energy source for intestinal cells and gut barrier

3-5g daily
athletes-muscle-recovery

Important for protein synthesis and muscle tissue maintenance

5-10g daily
liver-detoxification

Critical for ammonia detoxification and nitrogen metabolism

2-5g daily

Where to buy it

compare forms first

Look for L-Glutamic Acid at 2-6g per serving. The form that matters here is L-Glutamic Acid (Free Form).

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What else affects it

Beyond other supplements
!
Excessive gaba

GABA is inhibitory neurotransmitter opposing glutamate

Balance between excitatory and inhibitory neurotransmission
!
Alcohol

Alcohol disrupts glutamate-GABA balance

Alters excitatory-inhibitory neurotransmitter balance

How it works

  • Primary excitatory neurotransmitter in central nervous system
  • Essential fuel source for immune cells and lymphocyte function
  • Major energy substrate for intestinal cells and gut barrier integrity
  • Critical for protein synthesis and nitrogen metabolism
  • Important for ammonia detoxification and brain protection
  • Key component of glutathione synthesis for antioxidant function

Key findings

what the evidence supports
  • Primary excitatory neurotransmitter essential for learning and memory
  • Critical fuel source for immune cells and gut barrier function
  • Important for protein synthesis and nitrogen metabolism
  • Requires careful dosing due to potential excitotoxicity concerns

Sources: NIH Examine.com · data reviewed 2026-08-01

Compiled by Denis, who maintains this database and holds no medical qualification — every figure here is sourced or derived, never asserted. How we calculate it →

Common questions

What are the benefits of L-Glutamic Acid?

Documented effects: Enhanced brain function and cognitive performance; Improved immune system function; Enhanced protein synthesis and muscle health; Digestive health and gut barrier function. Primary excitatory neurotransmitter supporting learning and memory

How much L-Glutamic Acid should you take per day?

The common daily range is 2-6g. By goal — maintenance: 1-3g daily; therapeutic: 3-6g daily; cognitive enhancement: 2-5g daily; maximum: 10g daily (divided doses).

When is the best time to take L-Glutamic Acid?

With meals avoid evening. First effects are typically reported within 1-2 weeks for cognitive and immune benefits.

What are the side effects of L-Glutamic Acid?

At excessive doses: Moderate safety profile:, Headaches and nervous system overstimulation, Digestive upset with large doses, MSG-like sensitivity reactions, Potential excitotoxicity with excessive intake. Safety rating at normal doses is 7 out of 10.

What should you not take with L-Glutamic Acid?

Separate it from Excessive Gaba, Alcohol by two to four hours. GABA is inhibitory neurotransmitter opposing glutamate

Does L-Glutamic Acid interact with medications?

Documented interactions with anticonvulsants, psychiatric-medications. Discuss these with a pharmacist before combining.

How do you know if you need L-Glutamic Acid?

The marker is Plasma glutamic acid levels or neurotransmitter panels, optimal range 50-150 μmol/L. Common deficiency signs: Rare due to body synthesis:, Poor cognitive function, Impaired immune response, Digestive and gut problems.

Taken for

59 Immunity

Vitamin D3 · Vitamin C (Ascorbic Acid) · Comprehensive Immune Support Complex

 52 Brain & Focus

Caffeine · DHA · Fish Oil (EPA/DHA)