Is L-theanine An Effective Anxiety Treatment?

Micah Abraham, BSc

Written by

Micah Abraham, BSc

Last updated October 10, 2020

Is L-theanine An Effective Anxiety Treatment?

L-theanine may sound like an unknown substance, but there’s a good chance you have encountered it before: for example, in the cup of green tea you drank this morning. Questions have been raised about whether L-theanine, a type of amino acid, can have beneficial effects for those suffering from anxiety.

In this article, we'll explore some of the potential benefits and drawbacks of taking L-theanine for your anxiety.

How Does L-Theanine Work?

Because they have access to the central nervous system, psychoactive substances such as L-theanine are believed to have the ability to affect mental abilities and states including your perception of the outer world, the speed at which you think, and the mood you are in.

It is thought to have a stronger effect when combined with caffeine (the world’s most widely consumed psychoactive substance), which is also naturally found in green tea.

Possible Benefits of L-Theanine for Anxiety

Most of L-theanine’s effects have to do with promoting relaxation and positively affecting mood, though not all these effects have been shown to be consistent, and some have the potential to cause drug-seeking behavior when used excessively. L-theanine use triggers the following potentially positive responses in the brain for users with anxiety issues:

  • Affects Alpha Waves in the Brain Alpha waves are the brain waves associated with the state of waking relaxation. They reach their highest levels when a person is awake, relaxed, and has their eyes shut, but disappear when drowsiness or sleep commences. L-theanine has been shown to stimulate the brain’s alpha waves, suggesting that it can put users into a more relaxed state without ultimately causing them to fall asleep.
  • Increases Dopamine Levels Dopamine, the neurotransmitter that is released by the brain as a “reward” after engaging in “rewarding” activities such as consuming food or having sex, increases in the brain in response to L-theanine. Substances that cause the release of high levels dopamine can be addictive, resulting in a compulsion to seek the perceived feeling of “reward.” However, L-theanine produces low enough levels of dopamine that has not been shown to produce “seeking” or addicted behavior in lab tests on rats or in the (more limited) tests on human subjects.
  • Increases GABA (Gamma-Amino-Butyric Acid) levels GABA is an acid whose function is to inhibit or limit neuron activity in the brain. This has the effect of slowing neural processes and inducing a state of relaxation. There is some belief that L-theanine increases GABA levels.
  • Can Increase Serotonin Levels L-theanine does not consistently increase the brain’s serotonin “happy” neurotransmitter, associated with positive mood enhancement, but has been shown to result in an increase in some instances. Mood enhancement may limit anxiety by promoting positive thinking and discouraging obsessive negative thoughts.
  • (+ Caffeine) Improves Memory and Reaction Time When combined with caffeine, L-theanine has been shown to promote faster reaction time and improve memory through the interaction of calming mood improvement effects of L-theanine and the stimulant effects of caffeine. When anxiety makes it difficult to concentrate, or to remember names or essential facts (which can cause further anxiety later on), the combination of these two psychoactive substances can penetrate the brain and aid focus and information retention.

If you are a person who experiences anxiety that interferes with your functionality on a regular basis, the above effects may help to put you in a better frame of mind. However, it is good to remember that similar effects can be achieved through other means, as L-theanine use does entail some potential drawbacks. Both the drawbacks of L-theanine and alternative methods of achieving the above effects are outlined below.

Possible Drawbacks of L-Theanine for Anxiety

If you choose to use L-theanine as a treatment for anxiety, you should make sure that you are informed of its potential drawbacks, which depend largely on how the supplement is used. Knowing how to limit any adverse side effects and understanding why they may help to prevent any unnecessary stress when using this supplement.

  • Can Decrease Serotonin Levels While L-theanine also has the potential to increase serotonin levels in the brain, it has occasionally been shown to decrease them as well. A decrease of serotonin in the brain may result in an increase in stress and tension, which is the opposite of the desired effect for anxiety sufferers. Fortunately, the other positive effects L-theanine triggers in the brain may help to mitigate the adverse consequences of this possible effect.
  • (+ Caffeine) Mental Stimulant When L-theanine is ingested in the form of green tea (a substance that also naturally contains caffeine) or in combination with another caffeinated beverage or supplement, the side effects of the caffeine for a person with anxiety must also be taken into consideration. Caffeine stimulates the brain and increases the heart rate, which in turn increase the likelihood of strong reactions to anxiety-producing stimuli. L-theanine can temper this effect, but if caffeine is used to supplement L-theanine it should be used in small quantities. “Decaffeinated” green tea, for example, contains low levels of caffeine and may be a better choice than regular, fully caffeinated green tea.

Does L-Theanine Work?

As is usually the case with nutritional supplements and their effect on anxiety, there is very little evidence that L-Theanine is an effective treatment. Serious side-effects have not been documented, but there are also almost no studies that confirm that this supplement can affect your overall mood. When using these types of supplements, it's a good idea to talk to a doctor first and make sure that you never depend on it alone. Always make sure that you combine any supplement or medicine with lifestyle changes and techniques that do not require any supplementation, both to decrease the need for the supplement and to make sure that even if the supplement doesn't work, you're still reducing your anxiety.

Alternative Methods for Achieving L-Theanine Benefits

L-theanine benefits such as increasing serotonin levels and resulting in alpha-wave production in the brain can also be achieved through positive lifestyle choices that are free to make and can have additional anti-stress benefits. To find out what you can do to produce some of the benefits of L-theanine without using L-theanine itself, see the list below.

  • Go for a Run To get inside your brain and trigger “happy” chemicals without the help of blood-brain barrier crossing psychoactive substances, all you have to do is grab a pair of running shoes and get your body moving. When you exercise, your brain naturally produces the “happy” chemical serotonin, which helps to ease any stress or discomfort your body undergoes while it is working its muscles during exercise. Running, unlike taking supplements, also improves your body’s overall health—the health of the heart and lungs in particular. A healthy body with healthy organs is naturally less stressed out than an unhealthy one because it doesn’t have to work as hard to function.
  • Practice Meditation Meditating is a great way to relax both your body and your mind, as well as promoting those calming alpha brain waves, while also training your brain to enter a relaxed state through will alone— something that supplements can’t help you to do. Relying on a daily meditation session to relax you first thing in the morning or just before you go to sleep is both less expensive and more beneficial for your anxiety than relying on supplements, which you have to buy regularly and only work in the short term.
  • Join a Sports Team Team sports, like running, get your body moving and cause it to produce the “happy” chemical serotonin. They also usually involve casual social contact with others, which has been scientifically linked to improved mood and decreased stress in humans. Having teammates to talk with and relate to can also help to improve mood, as well as providing a distraction from your worries. When you have no distractions from your anxiety, small concerns have the opportunity to grow, resulting in further anxiety.

Decreasing anxiety by taking L-theanine as a supplement, either in the form of capsules or a mug of decaffeinated green tea, appears to be a low-risk way to address your anxiety issues. On the other hand, many of the positive effects of L-theanine plus additional benefits can be achieved through engaging in the lifestyle choices listed above.

Combining L-Theanine with Lifestyle Changes

Exercising while using L-theanine supplemented by caffeine should be avoided, especially if you are experiencing any heart or blood pressure problems. If you are using L-theanine in a caffeinated form but also exercise regularly, it is advisable to wait at least four hours after ingesting a caffeinated substance before exercising.

L-theanine supplemented by small doses of caffeine, such as the levels that can be found in “decaf” green tea, may be beneficial in combination with meditation. Meditation is an practice associated with slowing your heart rate rather than speeding it up, which means that low levels of caffeine don’t interact negatively with it. Also, the ability of L-theanine combined with caffeine to increase focus and improve memory may help to develop your mind’s ability to enter a meditative, relaxed state more easily.

No matter what you decide, however, never take L-theanine or any supplement alone. Studies have shown time and time again that there are non-pharmacological means to managing anxiety, and while theanine may be natural, it is still considered to be a medicine.

Questions? Comments?

Do you have a specific question that this article didn’t answered? Send us a message and we’ll answer it for you!

Ask Doctor a Question


Where can I go to learn more about Jacobson’s relaxation technique and other similar methods?

– Anonymous patient


You can ask your doctor for a referral to a psychologist or other mental health professional who uses relaxation techniques to help patients. Not all psychologists or other mental health professionals are knowledgeable about these techniques, though. Therapists often add their own “twist” to the technqiues. Training varies by the type of technique that they use. Some people also buy CDs and DVDs on progressive muscle relaxation and allow the audio to guide them through the process.

Ask Doctor a Question

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