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Is L-Theanine A Nootropic? (Everything You Should Know)

Tyler Sellers
Published by Tyler Sellers | Senior Coach
Last updated: August 2, 2023
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Being a fitness coach for more than 10 years, I've always advised my clients to read the label of the nootropic products they purchase and avoid proprietary blends.

This guidance opens the door to a slew of questions concerning specific components. L-theanine is one of these substances.

I took a few weeks, did extensive research on this ingredient, and compiled a guide so you know what it is and whether it is beneficial or you or not.

Quick Summary

  • L-theanine improves relaxation and mental well-being in those suffering from stress-related disorders and cognitive impairments.
  • L-theanine appears to have neuroprotective qualities, which improve brain performance and reduce stress.
  • L-theanine helps to maintain regular sleep patterns and improves an individual's general mood.

What Is L-theanine?

L-Theanine green tea in a cup

L-theanine is a kind of amino acid found in tea. It's also available as a supplement and is occasionally marketed as a natural cure for anxiety, tension, ADHD, and other ailments.

It has been demonstrated to help with relaxing without making you drowsy. It may also aid in the reduction of physiological stress responses and improve sleep quality.

This amino acid has been proven to provide cognitive enhancement benefits, calm the body, and safeguard the brain against age-related damage.

L-theanine was identified in 1949 and has been utilized as a food ingredient in Japan since then.

The US Food and Drug Administration (FDA) considers it safe for human ingestion and classifies it as a generally recognized safe substance (GRAS).

This is a nootropic that decreases the activation of the neurotransmitter glutamate, which is structurally related.

It has been demonstrated to increase relaxation and mental wellness in people suffering from stress-related illnesses and cognitive problems [1].

Many animal investigations have shown that this natural nootropic increases hippocampus activity and has anxiolytic effects through altering methionine and glutamate metabolism [2].

An 8-week experimental, double-blind, placebo-controlled research in individuals with schizophrenia and schizoaffective conditions discovered that this nootropic improved anxiety symptoms and cognitive performance [3].

How Does L-theanine Work In The Brain?

A woman thinking with light behind her head

L-theanine works in the brain by improving brain performance and health in two different ways.

1. Alleviate Both Physical and Emotional Stress

It promotes alpha brain waves, linked to mental relaxation and the ability to focus.

One research in South Korea included 20 healthy male participants aged 18 to 30. For seven days, one group received L-theanine supplements and the other a placebo.

The waves were monitored 40 minutes after the pills were administered.

The researchers looked at alpha wave power levels and they determined this amino acid increased the production of alpha brain waves, which are associated with mental relaxation and attention [4].

Scientists developed a device to analyze brain wave patterns in May 2016 clinically. This technology may detect cognitive impairment before it occurs [5].

2. Raises Neurotransmitter Levels

Studies have shown it enhances serotonin, dopamine, and GABA levels in the brain. It also lowers the excitatory neurotransmitter glutamate, which is linked to tension, agitation, and anxiety [6]

One study used 12 patients who went through four different trials.

One in which they ingested L-theanine at the beginning of the trial, another in which they stopped halfway through, and control tests in which they were given either a placebo or nothing.

The results demonstrated that L-theanine reduced heart rate and s-IgA levels linked to stress hormone. The researchers found that L-theanine could alleviate anxiety by inhibiting cortical neuron excitation [7].

L-theanine Benefits

An intellectual woman wearing glasses pointing at her head

L-theanine's cognitive effects can be attributed to its capacity to enhance neurotransmitter levels, enhance brain function, and lower stress levels.

These are some of its cognitive benefits:

  • Better mental concentration: Many people believe drinking black or green tea at work improves their mental focus. This concept is supported by this 2012 research [8].
  • Improved sleep quality: Several studies have shown that L-theanine may assist individuals in relaxing before bedtime, falling asleep faster, and sleeping better. These advantages might be attributed to the amino acid's unique effects on brain chemicals involved in safe, natural sleep aid. According to 2018 research, people reported improved sleep satisfaction after consuming 450-900 mg dose of L-theanine every day for 8 weeks. Participants in the study had generalized anxiety conditions and were on antidepressants [9].
  • Weight reduction: As part of a calorie-controlled diet, substituting green tea or a similar low-calorie hot beverage for a snack may help with weight loss. Green tea's L-theanine concentration can provide a savory flavor, commonly referred to as umami flavor. According to research, umami tastes may suppress hunger, aiding in weight reduction [10].
  • Lowering blood pressure: L-theanine might help relieve stress; anxiety reduction and enhanced relaxation can decrease heart rate. As a result, blood pressure may be reduced [11].
  • Greater cognitive performance: In 2016, researchers examined previous data on the advantages of L-theanine and determined that this nootropic might enhance both physical and mental well-being. They discovered that it appears to have neuroprotective properties that boost brain function [12].

"When used as a supplement, L-theanine may alleviate brain fog symptoms like memory issues and delayed response time.  It may also help lower stress and promote sleep, which may alleviate symptoms of fogginess."

- Lisa Hodgson, Clinical Nutritionist

After utilizing L-theanine for a month, my clients noticed an increase in their memory recollection and focus, especially after a strenuous day at work.

How To Take L-theanine For Cognition

Black coffee in the background

Your objectives will determine the way you use L-theanine. If you want to increase your cognitive health, combine a dose of L-theanine with coffee.

This is known as 'stacking,' and it's a frequent practice among nootropics users.

The idea behind combining a dose of L-theanine with coffee is that the two have complementing benefits.

Caffeine gives you a cerebral boost, while L-theanine affects stress by decreasing symptoms and enhancing attention.

L-theanine should be consumed on an empty stomach since food might reduce absorption. Depending on your preferences, you can use it in the morning or at night.

If you combine L-theanine with caffeine, take both in the morning to ensure that the caffeine does not compromise your night's sleep.

Some people take L-theanine on and off, whereas others do so regularly. If you want to cycle L-theanine, use it for 3-5 weeks, then give it a break for 1-3 weeks.

This will effectively deter the body from becoming acclimated to the impacts of L-theanine.

L-theanine Side Effects

Man holding toilet paper caused by diarrhea

L-theanine is among the least harmful nootropics accessible in terms of side effects.

It is non-toxic and widely accepted by the majority of people.

This is because L-theanine are amino acids that are a protein-building block. It is found naturally in tea leaves and is safe to take in large amounts.

Drowsiness is the most prevalent adverse effect of L-theanine. This is usually only seen at large dosages (600 mg and more).

Other possible adverse effects of L-theanine include:

  • Diarrhea
  • Headaches
  • Fatigue
  • Nausea

These adverse effects of L-theanine are infrequent and usually occur only at high dosages. If you encounter any negative effects, lower your dosage or stop taking it entirely.

L-theanine Clinical Research

Health professional doing research on laptop

A lot of studies have found that L-theanine improves brain function. It may specifically aid in maintaining regular sleep patterns, alleviating stress and its impacts, and improving a person's general mood. L-theanine may also help prevent the harmful consequences of aging on the brain.

1. Improving Mood

According to a 2011 study, L-theanine may enhance mood and cognitive function after stressful experiences.

L-theanine may help some people move forward following a period of anxiety or harsh circumstances [13].

2. Improving Attention And Memory

A 2011 research looked at the effects of L-theanine and green tea extract on attention and memory.

An electroencephalogram revealed enhanced brain theta waves (an indicator of attentiveness) after a single dosage of L-theanine in the brain's frontal, parietal, temporal, and occipital areas [14].

3. Enhancing Learning Ability

L-theanine has also been found in recent research to aid memory.

One study discovered that L-theanine's capacity to boost learning and cognitive function was mostly related to its capability to control Glutamate (Glutamic acid).

Glutamate is a molecular compound that regulates brain development, learning, and memory [15].

What Nootropics Are Similar to L-theanine?

Different nootropics similar to L-Theanine: Rhodiola Rosea, Bacopa Monnieri, Ashwagandha

The nootropics similar to L-theanine include Rhodiola Rosea, Bacopa Monnieri, and Ashwagandha.

1. Rhodiola Rosea

Rhodiola Rosea is a mountainous herb that thrives in cold climates. It has long been used to aid with fatigue and stress.

Rhodiola Rosea also boosts cognitive function and memory performance [16].

2. Bacopa Monnieri

Bacopa Monnieri has been used in traditional Ayurvedic treatment for millennia. It is well-known for improving cognitive and memory performance. Furthermore, Bacopa Monnieri has been demonstrated to lower anxiety and stress [17].

3. Ashwagandha

Ashwagandha is a herb that's been utilized as a Herbal remedy for ages. It is well-known for its capacity to alleviate anxiety and tension.

Ashwagandha has also been shown to enhance mental function and memory [18].


Is L-theanine Good For Your Brain?

Yes, L-theanine is good for your brain since it has been shown to bypass the blood brain barrier, and improve brain functioning by easing stress, enhancing mood, and maintaining regular sleep.

What Type Of Supplement Is L-theanine?

L-theanine is a type of supplement that comes in the form of amino acids found in black and green tea and various mushrooms. It is also available as a pill or tablet.

Can I Take L-theanine Every Day?

Yes, you can take L-theanine every day as it can ease stress, lower your cortisol levels, and get you to a state of zen in about 20 minutes.

What Are The Side Effects Of Too Much L-theanine?

There are no confirmed side effects of consuming too much L-theanine.

Should You Take L-theanine?

L-theanine is an incredible nootropic that has been shown to increase brain health and improve cognitive performance. Its side effects are mild and infrequent, rendering it a safe nootropic to try.

These nootropics can improve your cognition and lessen mental tension, which can help you achieve your objectives. When your brain is functioning well, you have more energy and are more driven to accomplish a task.


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