Glutamine, also known as L-glutamine or Gln, is a conditionally essential amino acid that plays a crucial role in various bodily functions, including cognitive performance.
As a nootropic compound, glutamine has gained popularity for its potential to enhance memory, learning, focus, and attention while reducing mental fatigue and stress.
This article will get into the science behind glutamine, its nootropic benefits, dosage recommendations, and safety considerations.
Table of Contents
What is Glutamine?
Glutamine ((2S)-2,5-Diamino-5-oxopentanoic acid) is the most abundant amino acid in the human body, making up a significant portion of skeletal muscle and serving as a building block for proteins.
It also acts as a vital fuel source for rapidly dividing cells, such as those in the immune system and intestinal lining.
As a glucogenic amino acid, glutamine can be converted into glucose when needed by the body.
Due to its benefits and need in the human body, glutamine is also used in parenteral nutrition.
What Is Glutamine’s Function in the Body?
Glutamine is involved in numerous bodily functions, including:
- Muscle protein synthesis
- Immune function enhancement
- Intestinal health promotion
- Wound healing
- Acid-base balance regulation
How is Glutamine Produced in the Body?
Glutamine is produced in the body by the enzyme glutamine synthetase and consumed by glutaminase. It’s involved in nitrogen metabolism and serves as a source of glutamate.
What are the External Sources of Glutamine?
Glutamine can be found naturally in various protein-rich foods, such as:
- Meat (beef, pork, chicken)
- Fish
- Dairy products (milk, yogurt, cheese)
- Eggs
- Beans and legumes
- Nuts and seeds
For those who require a controlled dosage, glutamine supplements are also widely available. The most common form of glutamine supplement is L-glutamine powder, which can be mixed with water or other beverages for easy consumption.
What are the Nootropic Benefits of Glutamine?
Glutamine has been studied for its potential nootropic benefits, which include:
- Enhancing memory and learning
- Increasing focus and attention
- Improving mood
- Reducing mental fatigue and stress
How Can Glutamine Enhance Memory and Learning?
Glutamine serves as a precursor to glutamate, an essential neurotransmitter involved in synaptic plasticity, which underlies learning and memory processes. Increased glutamine availability elevates glutamate levels, thereby enhancing cognitive functions related to memory formation and retrieval.
It also helps reduce ammonia toxicity in the brain. Elevated ammonia levels can impair cognitive function by disrupting neurotransmitter balance and neuronal energy metabolism. Albrecht et al. (2010) demonstrated that glutamine supplementation aids in detoxifying ammonia, thereby protecting neural function and supporting cognitive health.(1)
Furthermore, glutamine contributes to the synthesis of gamma-aminobutyric acid (GABA), another critical neurotransmitter.
GABA has inhibitory effects on the nervous system, promoting relaxation and reducing anxiety, which can indirectly benefit learning and memory by creating a more conducive mental state for cognitive processes.
What is the Impact of Glutamine on Focus and Attention?
Glutamine enhances focus and attention through several mechanisms.
Firstly, it provides energy to the brain by being converted into glucose, which is critical for optimal brain function.
Additionally, glutamine regulates the balance between glutamate and GABA, two key neurotransmitters. Glutamate is excitatory and promotes neural activation, while GABA is inhibitory and calms neural activity. The proper balance between these neurotransmitters is essential for maintaining focus and attention.
Furthermore, glutamine supports the synthesis of neurotransmitters like acetylcholine, which is vital for cognitive processes, including attention and concentration.
How Does Glutamine Influence Mental Fatigue?
Glutamine helps maintain the integrity of the blood-brain barrier, which can be compromised by stress and fatigue. Research found that glutamine supports the barrier’s function, preventing harmful substances from entering the brain.
During periods of high mental demand, glutamine serves as an important energy source for the brain. Newsholme et al. (2003) demonstrated that glutamine is metabolized to produce energy, aiding in cognitive function and reducing fatigue.(2)
Glutamine also has anti-inflammatory properties that reduce brain inflammation, which is linked to mental fatigue. Roth et al. (2002) reported that glutamine decreases the production of pro-inflammatory cytokines in the brain, thereby mitigating inflammation and its associated fatigue.(3)
How Does Glutamine Affect Mood and Stress?
Glutamine enhances the production of gamma-aminobutyric acid (GABA), a neurotransmitter that promotes relaxation and reduces anxiety. GABA inhibits neural activity, creating a calming effect on the brain.
Glutamine also helps lower cortisol levels, a stress hormone linked to adverse mood effects. A study demonstrated that glutamine supplementation reduces cortisol levels, mitigating stress responses and their negative impacts on mood.(4)
It supports serotonin synthesis, a key neurotransmitter in mood regulation. Jongkees et al. (2015) found that glutamine contributes to the production of serotonin, enhancing mood stability and overall emotional well-being.(5)
How to Use Glutamine for Cognitive Enhancement?
To experience the nootropic benefits of glutamine, it’s important to understand the recommended dosage, expected results timeline, and cycling strategies.
What is the Recommended Dosage of Glutamine?
The recommended dosage of glutamine for cognitive enhancement varies depending on individual factors such as age, weight, and health status. However, a general guideline is to consume 5-10 grams of glutamine per day, divided into 2-3 doses.
It’s essential to start with a lower dose and gradually increase it to assess tolerance and avoid potential side effects.
How Quickly Can One Expect Results from Glutamine?
The timeline for experiencing the nootropic benefits of glutamine varies from person to person. Some individuals may notice improvements in cognitive function within a few days of supplementation, while others may require several weeks to see significant changes.
Factors that can influence the timeline of results include:
- Individual biochemistry
- Dosage and frequency of supplementation
- Lifestyle factors (diet, sleep, stress levels)
- Concurrent use of other nootropics or medications
How Should Glutamine Be Cycled to Prevent Tolerance?
To maintain the effectiveness of glutamine as a nootropic and prevent tolerance, it’s recommended to cycle the supplement.
A common cycling strategy is to take glutamine for 4-8 weeks, followed by a 1-2 week break before resuming supplementation.
What Are The Side Effects and Safety Profile of Glutamine?
While glutamine is generally considered safe when consumed in recommended doses, it’s essential to be aware of potential side effects and interactions.
What are the Common Side Effects?
Common side effects of glutamine supplementation include:
- Digestive discomfort (bloating, gas, diarrhea)
- Nausea
- Headache
- Dry mouth
- Muscle or joint pain
Most side effects are mild and transient, resolving on their own within a few days of supplementation.
If side effects persist or worsen, it’s advised to reduce the dosage or discontinue use and consult a healthcare professional.
Is Glutamine Safe for Long-Term Use?
Long-term safety studies on glutamine supplementation are limited. However, it’s important to note that long-term use of high doses of glutamine (>40 grams per day) may lead to adverse effects, such as:
- Increased ammonia levels
- Insulin resistance
- Gastrointestinal distress
To ensure the safety of long-term glutamine supplementation, it’s recommended to:
- Adhere to the recommended dosage guidelines
- Cycle the supplement as described earlier
- Monitor for any adverse effects and adjust dosage accordingly
- Consult a healthcare professional before extending supplementation beyond 6 months
Who Should Avoid Glutamine Supplementation?
Certain individuals should avoid glutamine supplementation, including:
- Pregnant or nursing women
- Children and adolescents under 18 years of age
- Individuals with kidney or liver disease
- People with a history of seizures or neurological disorders
- Those with a sensitivity or allergy to glutamine or its components
Can Glutamine Interact with Other Medications?
Glutamine may interact with certain medications, such as:
- Anticonvulsants: Valproic acid, phenobarbital, etc.
- Chemotherapy drugs: Methotrexate, 5-fluorouracil, etc.
- Lactulose: used to treat hepatic encephalopathy)
It’s crucial to consult a healthcare professional before combining glutamine with any medication to avoid potential interactions and adverse effects.
- Albrecht, Jan, Magdalena Zielińska, and Michael D. Norenberg. “Glutamine as a mediator of ammonia neurotoxicity: a critical appraisal.” Biochemical pharmacology 80.9 (2010): 1303-1308.↩
- Newsholme, Philip, et al. “Glutamine and glutamate—their central role in cell metabolism and function.” Cell biochemistry and function 21.1 (2003): 1-9.↩
- Roth, Erich. “Nonnutritive effects of glutamine.” The Journal of nutrition 138.10 (2008): 2025S-2031S.↩
- Karami, Sajad, Majid Kashef, and Yaghob Mehri Alvar. “Protective effect of glutamine by the expression of HSP70 and reduction of cortisol on exercise induced stress.” Journal of Arak University of Medical Sciences 17.10 (2015): 65-73.↩
- Jongkees, Bryant J., Maarten A. Immink, and Lorenza S. Colzato. “Influences of glutamine administration on response selection and sequence learning: a randomized-controlled trial.” Scientific reports 7.1 (2017): 2693.↩