L-Theanine: Benefits for Sleep, Anxiety & the Brain

We look at L-Theanine and how you can add it to your diet. We also look at how it can benefit sleep, anxiety, and the brain and how it is an amino acid that can help you live a more relaxed and calmer life.

L-Theanine is an amino acid that can help you feel calm, relaxed, and stress-free. Sounds like a dream right? This is because L-Theanine helps to regulate serotonin and dopamine levels and this means it can completely better your mood and general wellbeing.

This article explores the benefits of L-Theanine and looks at the amino acid in more detail, whilst also warning you of any potential side effects.

From analyzing user experiences, we know it has helped countless people reduce their anxiety levels and make them feel great at work or school, so what are you waiting for? Let’s learn a little bit more about this mood-boosting supplement and find out if it’s just what your body needs.

What is L-Theanine?


L-Theanine is a non-dietary amino acid and is found in Camellia Sinensis, this is what we know as green tea leaves. Because of this, it is the main component in green tea and it was identified in 1948 in Japan as a green tea constituent. It’s also found in other plants such as mushrooms like Boletus badius.

L-Theanine reaches the brain quickly after consuming it orally and has a chemical structure that is similar to glutamate, a chemical in the brain and naturally occurring amino acid found in the body which helps to transmit nerve impulses in the brain. This means some effects of L-Theamine are similar to glutamate yet some seem to block the chemical completely.

L-Theanine can impact neurotransmitters that are involved with sleep, anxiety, and the brain and seem to play a large role in GABA function. It can initiate balance between neurotransmitters and this also leads to an improvement in the physical and emotional disturbances created by stress.

The amino acid has a wide range of brain-boosting, mood, and cognitive benefits and despite the fact you might not be getting much in your diet naturally, there are now supplements of the acid that promotes calmness, help with stress, benefits sleep, and combats anxiety.

How Does L-Theanine Work?

During stressful situations, neurotransmitters such as GABA which we mentioned in the previous section can often become depleted. L-Theanine works to boost these levels back to a normal range, whilst also increasing other ‘happy’ brain chemicals such as dopamine and serotonin.

L-theanine however lowers levels of excitatory neurotransmitters which amplify stress levels. It prevents an excess build-up of glutamate and this is the chemical that is related to cognitive disorders linked with age and can disturb the stress response natural in humans.

Moreover, L-theanine enhances alpha brain waves which increase alpha activity in the brain. This can improve focus and help you feel more relaxed without sending you to sleep. This is because alpha waves are directly associated with the state of waking relaxation.

As L-Theanine has access to the central nervous system, it is also believed to affect mental abilities and how you perceive the outer world, as well as how fast you think and what mood you are in. It’s thought to have an even stronger effect when mixed with caffeine, which is also naturally found in green tea.

Benefits for Sleep, Anxiety and the Brain

L-Theanine is known for its mood-enhancing effects, ability to help you destress, and can allow you to feel calm. Let’s take a look at how it gets to work:

L-Theanine Can Improve Your Sleep

Research has shown that L-Theanine can improve your overall sleep quality and help you get those 7 restful hours. Theanine exerts an anxiolytic effect and this can induce sleep. For a great quality sleep, the body must be able to wind down and unlike traditional sleeping pills, L-Theanine helps your body do this, without also acting as a sedative.

As L-Theanine also helps combat stress levels, it can help you feel more relaxed at night time, get you to sleep more easily, and can even help you reach a deeper sleep. This has to do with the brain chemicals which play an active role in sleep.

A study conducted in 2018, found people with generalized anxiety disorder and who were taking antidepressants, reported to have greater sleep satisfaction after taking just 450-900mg of L-Theanine each day for 8 weeks.

The alpha brain-boosting abilities in L-Theanine could also help your body and brain enter the NREM sleep stage, this is known as the first stage and is where your alpha brain waves are at their highest. L-Theanine could therefore help you fall asleep quicker as a result of its relaxation-boosting abilities.

L-Theanine Can Help with Symptoms of Anxiety

L-Theanine can help reduce symptoms of anxiety and these symptoms can include a racing heartbeat and an increased secretion of immunoglobulin A in saliva particles. It has a similar effect to an anxiety sedative, except it does not make you drowsy.

As it is an anxiolytic, it prevents the brain from producing an anxious response to stressful situations. Its main anti-anxiety effect however comes from the increased GABA synthesis and enhanced alpha brain wave activity.

When GABA is increased in the brain, it, in turn, increases levels of serotonin and dopamine, which is what promotes general wellbeing and a state of calmness. Most people notice this calming effect around 30-40 minutes after taking it and it can last around 10 hours.

Unlike a lot of anti-anxiety therapies, it doesn’t cause slowed reflexes, increase levels of drowsiness or affect concentration. There’s also no evidence of negative interactions with other drugs and this makes it a very popular treatment.

When L-Theanine is combined with caffeine, it can improve reaction time and memory through the interaction of calming effects and the stimulant of caffeine. This means when anxiety affects concentration, the combination of these two substances can penetrate the brain and improve focus and information retention.

Finally, L-Theanine can increase levels of a protein called brain-derived neurotrophic-factor which keeps the brain healthy. When the brain is healthy it can manage stress and anxiety as well as improve attention span and memory.

It Can Improve Brain Activity and Enhance Cognitive Skills

L-Theanine has special properties which make you feel both alert and relaxed at the same time. This means you can remain focused and calm when you’re in a stressful situation that requires a lot of brainpower and concentration.

A study found that just 200mg of L-Theanine can improve attention, performance, and reaction time. When paired with caffeine, this can also improve how focused you are on a particularly stressful cognitive task. The combination can also improve the accuracy of cognitive-based tasks and help you feel alert and awake for longer.

L-Theanine helps directly with memory and thinking skills and allows you to remain focused on a task for longer. It has also been linked to helping those with lower thinking skills perform a task that requires them to find words in a specific category.

L-Theanine can enhance alpha brain waves. As it is an anxiolytic, it can simplify these brain waves which are present when you let your mind wander or meditate. It can therefore help you with a creativity-oriented effect and focus on meditation sessions.

Are There Any Side Effects?

Surprisingly, there are no known side effects from consuming L-Theanine. This is because it has been classified as a safe (GRAS) dietary ingredient.

As you can find it easily in green or black tea, it can be a great addition to your diet and provide you with a whole range of different health benefits. A single cup of tea contains around 20mg of L-Theanine, yet studies show a daily dose, to be effective should be 200mg. To achieve maximum results, you could try supplementing L-Theanine.

However, despite the amino acid having no direct side effects, it might increase the risk of blood pressure dropping too low in people that are already prone to low blood pressure. This can cause a cold and feeble body and increase confusion in some people.

Despite the risk of side effects being extremely low, we still recommend talking to your doctor before adding any herbal supplements to your diet.

Experiences Shared on Reddit

Here are some reviews of L-Theanine from users and contributors on Reddit.

According to ‘Agnostix’:

‘When I first happened upon L-Theanine, I was shopping for the 'ideal' smart drug: one that had no side effects, addiction potential, or toxicity issues. I tried a lot of other stuff - nootropics, vitamin blends, herbal extracts, etc. L-Theanine remains the most effective, least expensive, and most widely available 'smart drug' that I've ever tried.’

According to ‘YunLihai’

‘I take 100 to 200 mg of L Theanine one hour before I have a social event or job interview, dentist visit, or other things that seem intimidating. The anxiety I usually feel in those moments is just gone. I can't believe it. Yesterday I had a job interview and I wasn't excited at all. I thought I would be anxious, stuttering, and shaking. I took only 100 mg of l Theanine which works great for me. I was confident, funny, and charming I felt like a different person. I guess this is what normal people feel like. When the anxiety was gone my true personality came out. I turned down so many opportunities in the past because of fear. Giving presentations in school or trade school /college etc. Reading out loud in class, which was a nightmare for me. Social interactions that always seemed awkward and cringe-worthy. All of that is gone now when I take L Theanine. I feel like I can make new career choices that I didn't see myself in. I can talk to people. I'm not saying L Theanine is a miracle but this is what I needed. If I had this sooner I would probably be financially stable by now. The studies back this up. Theanine inhibits cortical neuron excitation which reduces stress, and anxiety-related symptoms. It reduces anxiety and anxiety-related symptoms like increased secretion of immunoglobulin A in saliva.’

Where to Buy L-Theanine?

If you are not drinking black or green tea, or you want to add a supplement to your diet to feel the maximum health benefits and effects, you can buy L-Theanine online from places such as Amazon or nootropics specialists. However, we recommend checking this website out:

Frequently Asked Questions (FAQ)

Your questions answered.

What are the Benefits of Using L-Theanine?

L-Theanine benefits include its ability to boost brain activity and cognitive function, lower anxiety, promote healthy sleep whilst sending you to sleep quicker, keep you calm, and minimize the symptoms of psychiatric disorders like schizophrenia.

How Much L-Theanine Can You Take?

The recommended dosage for L-Theanine is around 200-400 mg per day, taken in two 200 mg doses. It is recommended to take one in the morning and one in the afternoon. L-Theanine is sold in tablet and powder form.

Should I Take L-Theanine Every Time I Drink Coffee?

The ideal ratio is 2:1, but simply taking an L-Theanine supplement and including caffeine in your diet like drinking a cup of coffee daily might work just as well for people. Alternatively, many supplements automatically combine the two ingredients.


To conclude, L-Theanine is a mood-enhancing amino acid that helps promote a healthy sleep schedule, can treat anxiety, and improve brain and cognitive function. This means including it in your diet can help you feel energized, alert, and think clearly.

It can help you focus on stressful tasks for longer and improve your overall mental performance. Since there are no known side effects and it can be found in accessible food sources like black and green tea, we recommend you try it out and experience the benefits for yourself!