L-Theanine: Benefits, Side Effects, Dosage (In-Depth)

L-Theanine: Benefits, Side Effects, Dosage (In-Depth)

Introduction to L-Theanine

L-Theanine is a natural constituent of green tea. It has been shown to have a number of benefits, including enhancing relaxation and reducing anxiety.

However, there are also some potential side effects and restrictions related to its consumption. This article discusses L-Theanine in greater detail, including its potential benefits and risks.

It also provides a summary of the standard recommended dosage and the recommended method of administration.

What Is L-Theanine?

L-theanine is an amino acid found almost exclusively in tea, where it may contribute to the beverage’s flavor and act as a mild relaxant. It’s produced in the leaves of the Camellia sinensis plant and is present in both black and green teas. It’s also found in some other plants, such as soybeans and corn.

How Does It Work?

Theanine works by binding to the same receptors in the brain that respond to dopamine, a neurotransmitter associated with feelings of pleasure and well-being. Therefore, taking L-theanine may enhance the mood and induce a state of relaxation. It may also help alleviate anxiety and depression.

What Are Its Potential Benefits?

L-theanine has a mild calming effect and improves brain function. Many people take it for anxiety and to relieve stress. It is also believed to enhance memory and attention span and improve mood. Some people take L-theanine to help with insomnia and other sleep problems.

It can also help relieve headaches and menstrual cramps. Some studies have suggested that it may be beneficial for people with attention deficit hyperactivity disorder (ADHD).

Increased Focus

L-Theanine may improve focus and concentration, without drowsiness or adverse side effects. The effect may be especially beneficial in individuals with ADHD who require extra stimulation to maintain focus, as well as those trying to reduce dependency on caffeine or other stimulants.

Anxiety and Stress relief

L-Theanine may increase alpha wave activity in the brain and reduce stress and anxiety. This may be useful for people who experience panic attacks or who suffer from conditions like depression and anxiety. It may also be useful for those who suffer from insomnia as it may also promote relaxation and a good night’s sleep.

Relaxes Muscles and Relieves Pain

L-Theanine helps to relax muscles and reduce pain because it increases gamma-aminobutyric acid (GABA) production in the brain, which is a neurotransmitter that affects the function of many organs in the body, including the muscles and nervous system.

GABA helps to calm and regulate our nervous system, thereby making us more relaxed and less tense. It also helps our bodies produce natural painkillers called endorphins, which relieve physical pain.

Improves Sleep Quality

L-Theanine may help with improving sleep quality and reducing the time it takes to fall asleep when taken before bedtime. However, the effect does not seem to be as dramatic as that achieved by some prescription drugs for sleep.

Taking L-Theanine may increase the time it takes you to fall asleep, but you may end up feeling more rested upon waking in the morning compared to if you had taken no supplement at all.

This is because you are less likely to wake up during the night when using L-Theanine, and you will sleep for a longer period of time overall.

Better Immunity

It boosts immunity and fights against disease-causing agents by stimulating the production of interferon – a group of proteins that help fight viruses and bacteria.

Research has also shown that L-Theanine may have a positive impact on immune function in the elderly and those undergoing treatment for HIV.

Fights Cancer

People who drank tea on a regular basis had about a 25% lower risk of colon cancer than people who did not drink tea. It has also been found that L-Theanine may help prevent the development of cancer in certain organs.

Studies have shown that mice fed a diet containing green tea extract were less likely to develop tumors in the colon compared to those given a normal diet. In addition, taking L-Theanine supplements on a daily basis has been found to reduce the risk of liver cancer by as much as 50%.

Blood flow management

L-Theanine prevents the release of certain chemicals that cause blood vessels to narrow, resulting in improved blood flow and increased oxygenation to the brain and other tissues.

Improved blood flow helps prevent the damage caused by high blood pressure and reduces the risk of developing a number of serious medical conditions, including heart disease, stroke, and hypertension.

L-Theanine may also help reduce cholesterol and triglyceride levels, which may reduce the risk of developing atherosclerosis and coronary heart disease.

Level up your mind.

What Are The Risks Of Taking It?

Allergies are rare but some people may experience nausea or skin rashes after taking L-theanine. Occasionally, it can interfere with certain medications or cause other side effects.

Pregnant women should avoid taking it because it may affect the development of the fetus. Children under the age of 12 should not be given L-theanine without medical advice. People who are allergic to caffeine should not take it because it contains a small amount of caffeine. People with glaucoma should not take L-theanine because it may raise pressure in the eye.

Side Effects Caused By L-Theanine


Some of the most common side effects of L-theanine include headaches, dizziness, and nausea. These usually disappear after the body gets used to taking the supplement and the dose is adjusted accordingly.


Headache is a relatively common side effect of L-theanine. In most cases, it is caused by overconsumption of caffeine in combination with L-theanine. It typically goes away once the daily dose is reduced or eliminated.


Some people experience lightheadedness when they first start taking L-theanine. It usually goes away within a few days of starting the supplement. If the problem persists even after adjusting the dose, contact your healthcare provider for advice.


L-Theanine is often used to treat Anxiety, but sometimes it can cause it. It is usually a temporary side effect that will go away after a few days if proper precautions are taken. If you experience anxiety symptoms after taking L-theanine, try reducing the amount you are taking or stop taking it altogether and see if the symptoms go away on their own.


It is usually caused by an interaction with another medication or allergy to L-theanine. Drink plenty of water to prevent dehydration. The symptoms of diarrhea may improve after a few days as your body adjusts to the supplement.


There is no documented evidence that suggests that L-Theanine can cause vomiting. It is usually caused by an overdose of L-Theanine.

When consuming L-Theanine, It is recommended to not consume over 400mg per day. Everything under 400mg is safe and should not have any side effects.

Frequently Asked Questions (FAQs)

What are the benefits of L-Theanine?

In healthy individuals, supplementation with L-Theanine can increase mental focus, reduce anxiety and stress, enhance memory, and improve mood. It can also improve sleep and reduce fatigue in people who suffer from a lack of sleep.

How good is L-Theanine for Anxiety?

L-Theanine has been shown to be effective in reducing stress and anxiety and promoting relaxation in individuals suffering from these disorders. However, its effectiveness may be limited in people with certain health conditions such as fibromyalgia, depression, and anxiety due to medical reasons.

What are the side effects of taking L-Theanine?

L-Theanine is very popular and does not cause many side effects for most people. However, some people may experience dizziness, headache, nausea, stomach discomfort, or a tingling sensation in the mouth after taking L-Theanine.


L-Theanine is a safe supplement and has little to no side effects, however, some people may experience mild side effects such as nausea, headaches, or dizziness.

These can usually be controlled by reducing the dose of the supplement or taking a few days off to recover. Benefits of L-Theanine include improved memory function, increased energy levels, and reduced stress.

Taking L-Theanine can also help improve the symptoms of anxiety and depression.

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George Hernandez

George specializes as a Nootropic Expert with a Ph.D. in Neuroscience and a BA in philosophy, George has an excellent understanding of the workings of the human brain. He also helps to synthesize several medical papers regarding the efficacy of nootropics. He also tested the most popular nootropic supplements on the market and is making transparent reviews on each of them on this website.

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