Understanding Your Nutrition Diet: What is another name for L-theanine?

October 21, 2025 •

4 min read

According to a 2025 review, L-theanine has been poorly studied to date with inconsistent research quality, especially in robust clinical trials. Despite this, it remains a popular supplement for its calming properties, leading many to ask: What is another name for L-theanine?

Quick Summary

This article examines the various scientific and trade names for the amino acid L-theanine, outlining its primary sources in tea leaves and mushrooms. It explains the physiological benefits, including stress reduction, improved sleep quality, and enhanced cognitive function, contrasting its effects with caffeine.

Key Points

Alternative Names: L-theanine is also known by its chemical names, such as N-ethyl-L-glutamine and gamma-glutamylethylamide, and the trade name Suntheanine.
Stress and Anxiety Relief: This amino acid helps reduce stress and anxiety by promoting alpha brain wave activity, creating a state of relaxed alertness without sedation.
Improved Sleep Quality: L-theanine does not cause drowsiness directly but improves sleep quality by calming the nervous system and reducing anxiety, potentially decreasing sleep latency.
Synergy with Caffeine: When combined with caffeine, L-theanine can mitigate the stimulant's jittery side effects while preserving its positive effects on focus and cognitive performance.
Natural Sources: The most common natural dietary sources are the leaves of the tea plant (Camellia sinensis), found in green, black, and white teas, as well as some mushrooms.
Neurotransmitter Modulation: L-theanine influences brain chemistry by increasing levels of inhibitory neurotransmitter GABA and modulating dopamine and serotonin.
Blood Pressure Support: Studies suggest L-theanine can help manage blood pressure, especially in high-stress situations, by promoting relaxation and counteracting vasoconstrictive effects.

Disclaimer

Information is for general knowledge, should not be taken as medical advice, and should consult with a healthcare provider.

The Many Monikers of L-Theanine

While L-theanine is the most common and widely recognized name, this unique amino acid is known by several other chemical and trade designations. Knowing these can be helpful for those researching supplements or exploring scientific literature.

Chemical and Scientific Names

N-ethyl-L-glutamine: This is a common and accurate chemical name for the compound. It describes the molecular structure, where an ethyl group is attached to the glutamine molecule.
Gamma-glutamylethylamide: This name also describes the compound's chemical structure, specifically the amide formed from ethylamine and L-glutamic acid at its gamma side chain.
2-Amino-4-(ethylcarbamoyl)butyric acid: This is another, more technical, chemical identifier for L-theanine.

Trade Names

Suntheanine: This is a well-known brand name for L-theanine. It signifies a specific, patented form of the amino acid.
Teanina: This is the Spanish name for theanine.

How L-Theanine Impacts Your Health

Beyond just a name, L-theanine is prized for its influence on mental well-being and cognitive function. It is particularly known for promoting relaxation without causing drowsiness, making it a key component in a balanced nutritional diet aimed at supporting brain health. Its effects stem from its ability to cross the blood-brain barrier and modulate neurotransmitter activity.

Mental and Cognitive Benefits

L-theanine has been shown to offer a range of mental benefits, particularly under stressful conditions. Research indicates that it increases alpha brain wave activity, which is associated with a state of relaxed alertness and can lead to improved attention and focus. It also influences key neurotransmitters:

GABA: L-theanine helps increase levels of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter that has a calming effect on the nervous system.
Dopamine and Serotonin: It can also modulate dopamine and serotonin levels, contributing to improved mood and overall psycho-emotional well-being.
Stress Management: By affecting these neurotransmitters, L-theanine can help reduce physiological responses to stress, such as lowered heart rate and blood pressure, particularly in individuals with high stress responses.

Improved Sleep Quality

L-theanine does not act as a sedative but rather enhances sleep quality through anxiolysis and relaxation. It can help reduce sleep onset latency (the time it takes to fall asleep) and decrease sleep disturbances. This is especially beneficial for those whose sleep is negatively impacted by stress or anxiety.

L-Theanine and Caffeine: A Balancing Act

One of the most common ways people consume L-theanine is through tea, which also contains caffeine. The combination is well-researched for its synergistic effects, where L-theanine can mitigate some of the less desirable side effects of caffeine, such as jitteriness and increased anxiety. The pairing can promote a state of calm alertness, enhancing focus without overstimulation.

Comparison Table: L-Theanine vs. Caffeine vs. Combination


Feature	L-Theanine Alone	Caffeine Alone	L-Theanine + Caffeine
Effect on Alertness	Promotes relaxed alertness and focus.	Increases alertness and wakefulness.	Enhanced focus and attention with reduced jitteriness.
Anxiety/Stress	Reduces stress and anxiety.	Can increase anxiety and restlessness.	Mitigates caffeine's anxiety-inducing effects.
Blood Pressure	May lower blood pressure.	Can increase blood pressure.	Counteracts caffeine's vasoconstrictive effects.
Sleep Impact	Improves sleep quality indirectly by promoting relaxation.	Can disrupt sleep patterns.	Less likely to interfere with sleep compared to caffeine alone.
Overall Feeling	Calm and relaxed.	Stimulated and energized.	Focused, energized, but calm.

Dietary Sources and Supplementation

The most prominent natural sources of L-theanine are various types of tea leaves and some specific mushrooms. For those seeking more concentrated amounts, dietary supplements are widely available.

Tea Leaves: L-theanine is naturally abundant in green, black, white, and oolong teas, derived from the Camellia sinensis plant. Green tea often contains slightly more L-theanine than black tea, but the amount can vary based on steeping time and leaf quality.
Mushrooms: L-theanine has also been identified in the mushroom Boletus badius.
Supplements: L-theanine is sold as a dietary supplement in capsules, tablets, and powders. These offer a more concentrated form than simply drinking tea.

Potential Risks and Considerations

L-theanine is generally considered safe for most people when used as directed. However, as with any supplement, there are considerations to keep in mind:

Usage Guidelines: Most studies have focused on short-term use, and long-term effects are not as well-understood. While amounts used in studies have varied, excessive intake may increase the risk of mild side effects like headaches or sleepiness.
Interactions: L-theanine can lower blood pressure, so those on antihypertensive medications should monitor their blood pressure closely. It may also interact with sedative medications or certain cancer drugs.
Pregnancy and Breastfeeding: Due to insufficient research on its effects, L-theanine is not recommended for pregnant or breastfeeding individuals.

Conclusion

So, what is another name for L-theanine? You can call it N-ethyl-L-glutamine, gamma-glutamylethylamide, or perhaps by the trade name Suntheanine. Regardless of the name, this amino acid offers a powerful and gentle approach to promoting mental calm and focus, making it a valuable addition to a wellness-focused nutrition plan. Whether enjoyed in a cup of tea or taken as a supplement, it provides a natural way to support a balanced mental state without causing sedation. As with any dietary change or supplement, consulting a healthcare provider is recommended to determine the best approach for your individual needs.

For more in-depth information on its mechanism of action, visit the research analysis on ScienceDirect(https://www.sciencedirect.com/science/article/pii/S2213453021001324).

Frequently Asked Questions

L-theanine's primary function is to promote relaxation and calm without causing drowsiness. It achieves this by increasing alpha brain wave activity and modulating neurotransmitters like GABA and dopamine.

Yes, for dietary supplement purposes, the names L-theanine and theanine are generally used interchangeably. The 'L' simply specifies the natural, biologically active form of the amino acid found in tea.

Yes, L-theanine is believed to help ease anxiety by influencing mood-regulating neurotransmitters and promoting relaxation. Several studies have linked L-theanine supplementation with reduced stress and anxiety levels.

The main dietary sources of L-theanine are tea leaves, particularly green, black, and white teas. It is also found in some species of mushrooms, like Boletus badius.

L-theanine is typically taken orally. For specific usage guidelines, it is important to consult a healthcare professional and follow product instructions.

Yes, many people combine L-theanine and caffeine (the active ingredient in coffee) to get the benefits of both. L-theanine can help temper the jittery effects of caffeine while enhancing focus.

L-theanine is generally considered safe and side effects are rare, especially when used as directed. Mild, potential side effects in larger amounts may include headache, nausea, or upset stomach.