L-Theanine Review: Brain Boosting and Mood Enhancing Effects

L-Theanine Supplement: Brain Boosting and Mood Enhancing Review

What is L-Theanine and What Does It Do

L-theanine is a naturally occurring amino acid which is found in both green and black tea leaves. It is also found in a small quantity in Bay Bolete mushrooms – also known as “imleria baida”.

As compared to D-theanine (an amino acid), L-theanine has more health benefits. L-theanine is a natural nootropic that was first detached from green tea in 1949. Since then it has been the center of various medical studies.

Many scientific and medical studies across the world prove that L-theanine provides multiple health benefits like boosting mood, lowering stress levels, enhancing concentration abilities, and protecting the heart and brain from severe diseases.

It has also been observed that L-theanine becomes more effective when combined with caffeine like green tea. The two work well together. For instance, caffeine helps to expand your concentration span while L-theanine reduces the nervous jitters that you might suffer because of the stimulant.

Advantages of Taking L-Theanine Supplements

Advantages of Taking L-Theanine Supplements

How L-Theanine Works in the Brain to Block Anxiety and Stress

Although the exact mechanism of L-theanine is not clearly specified, this substance does provide benefits by affecting the brain directly. L-theanine has the ability to cross the blood-brain barrier effortlessly. Once it crosses the barrier, it instantly reaches the brain and targets different brain chemicals that regulate feelings of arousal, stress, anxiety, pleasure, and attention. These brain chemicals are serotonin, dopamine, GABA, and Norepinephrine, to name a few.

One of the reasons why L-theanine affects the brain chemicals so quickly is because this amino acid is a quick absorbent. It seamlessly absorbs in the bloodstream and acts quite fast. L-Theanine improves the learning ability and memory power by increasing levels of serotonin and dopamine.

It also regulates the functioning of brain wave activity which relaxes the mind and improves attention. Moreover, it helps to eliminate harmful toxins that are present in your brain. It does so by increasing glutathione levels – an important antioxidant molecule. It also positively affects the functioning of GABA by making it more effective and efficient.

Amino Acid
Focus Focus
Stress Stress
Brain Function Brain Function

How It Works:

  • Helps in focusing and attending.
  • Enhances moos and reduces anxiety and stress.
  • Has neuroprotective properties.
100 – 200mg per day
Rated Possibly Safe

9 Effective Benefits And Uses Of L-Theanine

L-Theanine for Mood Enhancing

L-Theanine for Mood Enhancing

1. L-Theanine Reduces Anxiety and Stress

A hot cup of green tea is beneficial for everyone, but research concludes that it is most helpful to those who are dealing with high levels of anxiety. Five trials with 104 participants showed a decrease in levels of stress and anxiety when these participants took L-theanine supplements. Since these participants were chronic sufferers of stress and anxiety, L-theanine supplements substantially helped them to relax.

A study published in the Journal of Clinical Psychiatry found that L-theanine instantly decreased levels of anxiety among those who had schizophrenia or schizoaffective disorder. The research found that L-theanine instantly calmed both their body and mind.

2. Tumor and Cancer Treatment

A 2011 study observed that L-theanine present in the Bay Bolete mushrooms can improve the effectiveness of chemotherapy drugs. Since L-theanine has the ability to reduce the symptoms of chemotherapy, the authors of the same study believed that L-theanine also possesses the ability to fight cancer.

Although there is no solid evidence to support this claim, many studies suggest that people who drink tea regularly have lower chances to suffer from cancer. Chinese researchers found that women with ovarian cancer were able to live longer because they drink at least one cup of green tea regularly.

Another study observed that those who were excessive tea drinkers were less likely to suffer from pancreatic cancer as compared to those who aren’t.

3. Improves Brain Function

One of the advantages of taking L-theanine supplements is that they protect brain neurons from getting damaged. They do so by blocking the over-stimulation of the brain cells.

They also support the brain health by supplying the right amount of oxygen. L-theanine supplements make sure that the brain cells get enough oxygen so that they can function well all the time.

4. Better Immunity

Some studies show that L-theanine can improve the function of the immune system. A study published in Beverages Journal concluded that L-theanine can maintain the upper respiratory tract by protecting it from harmful infections.

Another study found that L-theanine can treat inflammation in the intestinal tract by reducing toxins present in it. However, more research needs to be done in order to support these findings.

5. Increased Focus

When combined with caffeine, L-theanine can expand your concentration span and improve your attention. A 2013 study showed that young adults, who took moderate levels of L-theanine with caffeine, in the doses about 97 mg and 40 mg respectively were able to concentrate better during challenging tasks. Overall, the participants also felt more active and less drowsy. Another study noted that these effects can occur just within 30 minutes, to say the least.

6. Protects the Heart and Blood Vessels

A 2012 study found that L-theanine supplements can reduce the high blood pressure of those who experienced an increase in their blood pressure after engaging in stressful tasks.

The same study concluded that caffeine alone can be less effective when it comes to protecting your heart and preventing heart diseases.

7. Increases Sleep Quality

Some research points out that L-theanine can help you get a good night’s sleep. For instance, one study found that L-theanine improved the quality of sleep in humans as well as animals when they consumed 250 mg and 400 mg doses of L-theanine supplements.

8. helps with Weight Loss

L-theanine with the help of green tea can lower the production of fatty acids in your body. This way, you can stop yourself from gaining extra calories.

9. May Heal Stomach Ulcers

If you consume 10 mg dose of L-theanine, you can successfully heal stomach ulcers. However, make sure that you don’t exceed the dose above 40 mg as it may aggravate the ulcers.

L-Theanine Protects Brain Cells and Promotes Cognitive Function

L-theanine for Brain Boosting Supplement

L-theanine for Brain Boosting Supplement

As discussed earlier, L-theanine supplements can improve your attention span and memory. Some studies have supported this view based on their positive findings.

In one of the studies, the combination of L-theanine and green tea strengthened the memory of participants who had suffered from minor brain damage. These patients consumed L-theanine supplements along with green tea after a mental exercise. As a result, they experienced a considerable improvement in their attention span. They were also able to focus far better than before.

It also elevates alpha brain waves which help soothe your mind while keeping you highly focused and alert at the same time. L-theanine supplements also improve the performance of certain types of protein that enhances nerve growth.

Risks and Side-Effects of L-Theanine

It doesn’t have any serious side-effects. Therefore, it is considered safe to consume it in the form of supplements or drink teas with L-theanine

Although research has proven L-theanine to possess anti-tumor properties, some teas that contain L-theanine may prove to be harmful to those with cancer. According to Memorial Sloan Kettering Cancer Center, green tea can reduce the efficacy of bortezomib. Hence, it is better that you first consult your doctor before you consider the intake of L-theanine supplements or L-theanine-based tea.

Drinking too much coffee or any other form of caffeine can result in several health issues like nausea, upset stomach, or irritation. However, you can reduce these side-effects by controlling the high consumption of green tea or L-theanine supplements.

Pregnant women should also avoid drinking too much caffeine. The best they can do is to consult a doctor and ask what is appropriate for them. The same rule applies to children as well.

L-theanine can also lower your blood pressure if you take medications for blood pressure already. This way, your blood pressure can go too low. Thus, when taking L-theanine supplements it is important that you avoid the use of other medications or drugs.

Safe Dosage Recommendations for L-Theanine

The right dosage of L-theanine depends on the consumer’s age and health. Unfortunately, there hasn’t been much research conducted to determine the appropriate dosage for everybody.

There have also been no reports of overdose or serious side-effects of consuming L-theanine supplements. It is also generally considered safe to drink green tea by people. For centuries, people have been drinking caffeine that contains L-theanine. They have hardly experienced any dangerous side effects, which is why people consume it without fixating over its dosage. But it totally depends on the strength of your tea. For instance, scientists estimate that one cup of black tea contains 20 mg of L-theanine. If you want to take maximum benefits from L-theanine, you will have to drink at least 5 to 10 cups of black tea.

How much L-theanine can you take?

However, when it comes to taking L-theanine supplements it is imperative to ensure that you don’t take it with other drugs as this would make the supplement less effective. In most scientific studies, the dosage of L-theanine was kept between 100 to 200 mg.

Theanine Supplement Increases Sleep Quality

Theanine Supplement Increases Sleep Quality

Is L-Theanine a Good Nootropic?

Nootropics, also known as smart drugs effectively enhance your brain function. One notable fact about L-theanine is that it boosts brain function in various ways.

L-theanine improves the alpha brain waves which in turn increase your concentration span. One South Korean study found that L-theanine tablets promote the release of alpha brain waves – associated with relaxation and concentration – when 20 healthy men aged 18 – 30 years consumed L-theanine tablets as compared to the other group that consumed a placebo daily for 7 days.

Brain waves of participants that consumed L-theanine were measured after 40 minutes and there was an improvement observed in the wave power values.

Moreover, L-theanine helps stimulate the production of neurotransmitters. Clinical research shows that L-theanine increases dopamine, serotonin, and GABA in your brain. All these neurotransmitters alleviate symptoms of stress, tension, and anxiety, enhancing your cognitive function in the process.

A study conducted in Japan showed that L-theanine inhibited the symptoms of acute stress when 12 participants took L-theanine at the beginning of the experiment and then in the middle of the experiment.

The researchers further noted that L-theanine helped reduce the increased heart rate. With a lower level of stress, the participants were able to concentrate better. There was an improvement in their neuron function as there was an inhibition of the cortical neuron excitation in the brain.

Where Can You Get Good L-theanine?

You can find L-theanine pills useful for several purposes. You can use it for enhancing your anxiety, focus, promoting calmness and relaxation, and improving heart performance. Finding high-quality L-ethanine supplements aren’t that difficult. You can find them online or in pharmaceutical stores.

Research indicates that many supplement makers use their own extraction methods for L-theanine. If the production of L-theanine is not done properly, it may contain more than just the “L” form of theanine. It may also end up having other forms of theanine such as a “D” form of theanine.

D-theanine works differently in the body and doesn’t have the similar effects like L-theanine. Though D-theanine is not dangerous, its consumption may not let you have all the benefits of pure L-theanine. Hence, before you buy L-theanine supplements, read the labels and reviews by users who have tried this product. With a thorough research from your end, you’ll be able to find the right supplement that also works for you.

L-Theanine Reviews

L-theanine is a popular supplement, used by many people worldwide. Here are some of the reviews of individuals who used this mood-enhancing and brain-boosting supplement:

“There was a time in my life when I used to stay awake late into the night. I had anxiety problems and this is why I couldn’t sleep better at night. A friend of mine who is also a doctor suggested me L-theanine supplements. I have been taking it for over three weeks now and I have seen a vast improvement in myself. I don’t feel as agitated as I used to!”

“I have been taking L-theanine pills for boosting my memory for over four months. My memory has improved a lot!”


  1. L-theanine relieves positive, activation, and anxiety symptoms in patients with schizophrenia and schizoaffective disorder: an 8-week, randomized, double-blind, placebo-controlled, 2-center study.
  2. The acute effects of L-theanine in comparison with alprazolam on anticipatory anxiety in humans
  3. L-Theanine extends lifespan of adult Caenorhabditis elegans.
  4. A 13-week dietary toxicity and toxicokinetic study with l-theanine in rats.
  5. The combined effects of L-theanine and caffeine on cognitive performance and mood.
  6. The combination of L-theanine and caffeine improves cognitive performance and increases subjective alertness.
  7. Assessing the effects of caffeine and theanine on the maintenance of vigilance during a sustained attention task.
  8. The effects of L-theanine, caffeine and their combination on cognition and mood.
  9. L-theanine and caffeine improve task switching but not intersensory attention or subjective alertness.
  10. Pharmacokinetics of theanine enantiomers in rats.
  11. Transmural potential changes associated with the in vitro absorption of theanine in the guinea pig intestine.
  12. Inhibition by theanine of binding of [3H]AMPA, [3H]kainate, and [3H]MDL 105,519 to glutamate receptors.
  13. Theanine, an ingredient of green tea, inhibits [3H]glutamine transport in neurons and astroglia in rat brain.
  14. L-theanine relieves positive, activation, and anxiety symptoms in patients with schizophrenia and schizoaffective disorder: an 8-week, randomized, double-blind, placebo-controlled, 2-center study.
  15. l-Theanine, an amino acid in green tea, attenuates beta-amyloid-induced cognitive dysfunction and neurotoxicity: reduction in oxidative damage and inactivation of ERK/p38 kinase and NF-kappaB pathways.


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