How Much L-Theanine to Take for Anxiety

Lin Yutang, a famous Chinese writer, once said, “There is something in the nature of tea that leads us into a world of quiet contemplation of life.” -and he was absolutely right.

L-theanine is a unique amino acid found primarily in green tea (Camellia sinensis), black tea, and the edible bay boletus mushrooms, also known as Xerocomus Badius. Scientists have been studying this phytochemical for its ability to promote a sense of calm, reduce insomnia, easing stress and generalized anxiety. Furthermore, many believe L-theanine crosses the blood-brain barrier to exert its effects directly on the brain within 30 minutes.

Currently, this amazing compound is available in capsules or tablet form of 200mgs. If you’re considering adding bioactive components to your wellness routine, stay with us to discover how much L-theanine to take for anxiety.

L-Theanine for Anxiety and Depression

Unfortunately, at some point in our lives, we go through difficult times. Sometimes a disturbing event can make us feel depressed or anxious.

Depression is a severe mood disorder that affects how you feel, think, and act. Activities that you once enjoyed are no longer exciting, and a feeling of sadness seems to be here to stay. 

This disorder affects more than 300 million people worldwide. According to the World Health Organization (WHO), it is the leading cause of disability and the second most common psychiatric disease after anxiety, an intense feeling of fear or apprehension about what’s to come that interferes with your everyday life. This last one is the most typical emotional disorder that influences people of all ages and genders. In fact, 1 in 5 people is affected by one or both diseases.

Psychiatrists treat anxiety and depression with antidepressants, but these drugs can often have serious side effects. For this reason, more and more people are starting to look into alternative treatments. L-Theanine might be the natural supplement you’re looking for to combat the symptoms of both conditions safely. 

This non-proteinaceous amino acid, primarily found in green tea, is popular in Asian countries for its anxiolytic effects. Besides modulating aspects of the function of our brains, it also has several health benefits, including mood improvement, cognition, and reduction of anxiety-like symptoms.

Early research shows that taking l-theanine orally at bedtime for eight weeks decreases symptoms and improves sleep in people with depression. However, it takes more than a cup of black or green tea to achieve this calm state of mind. This effect only appears with higher doses. If you’re interested in learning how much l-theanine to take for anxiety, keep reading below.

Does L-Theanine Work for Anxiety?

Many studies back up the tremendous anxiety-reducing effects of l-theanine. Human electroencephalogram (EEG) studies have shown that L-Theanine increases the activity in the alpha frequency band, which you can see in the EEG during a normal wakeful state where the subject is quietly resting. These observations helped discover that L-Theanine relaxes the mind without inducing drowsiness, slow reflexes, or impaired concentration.

Another study presented in the Journal of Nutrition & Intermediary Metabolism concluded that this compound could reduce acute stress and anxiety in people experiencing stressful situations and participants with an existing mental condition. Another research supported these claims, as it focused on people who have schizophrenia or schizoaffective disorder. This study published in the Journal of Clinical Psychiatry found that L-theanine decreased anxiety and improved the symptoms of these conditions. 

As a form of protection, not all the substances can cross over into the brain, but L-Theanine is different. Unlike many medications that can’t pass through the blood-brain barrier, this non-dietary amino acid uses the leucine-preferring transport system to take a ride across this barrier, allowing it to target the brain directly.

Once past the blood-brain barrier, it increases alpha brain wave activity and offers general neuroprotective effects. Meanwhile, it raises brain levels of different neurotransmitters, such as serotonin and dopamine, which are the chemicals responsible for mood, and gamma-aminobutyric acid (GABA), an important inhibitory neurotransmitter. 

In addition, L-theanine stabilizes cognitive function affected by stress hormones, blocks the binding of L-glutamic acid to glutamate receptors in the brain, and inhibits cortical neuron excitation, which can have anxiolytic effects.

How Much L-Theanine Should I Take for Anxiety?

Studies have shown that 200 mg of L-theanine can help reduce resting heart rate, indicating its ability to promote relaxation. While some academic works suggest that this natural compound may hold the key to improved mental health, it’s crucial to notice that some results in clinical research studies are inconsistent. When compared to the prescription medication alprazolam (1 mg),  there are non-significant anxiety-reducing effects.

On the bright side, L-Theanine is usually well tolerated. Currently, there are no published reports of severe adverse side effects. Rarely, headaches and facial tics may appear. Furthermore, unlike benzodiazepines, this naturally occurring amino acid does not lead to tolerance and dependence when used over long periods.

There are no interactions with other natural products or conventional prescription medications except for antihypertensive (may potentiate its activity) and stimulant drugs (may decrease its effects) such as:

  • Captopril (Capoten)
  • Enalapril (Vasotec)
  • Losartan (Cozaar)
  • Valsartan (Diovan)
  • Diltiazem (Cardizem)
  • Amlodipine (Norvasc)
  • Hydrochlorothiazide (HydroDiuril)
  • Furosemide (Lasix)
  • Diethylpropion (Tenuate)
  • Epinephrine
  • Phentermine (Ionamin)
  • Pseudoephedrine (Sudafed)

Best Dose of L-Theanine for Anxiety

Although there’s currently no official theanine dosage guideline in the United States, studies have shown that doses between 50 and 200 mg of L-Theanine are needed to enhance alpha brain wave activity. 

You will experience the calming effects of this compound 30 minutes after ingestion, and it may last within 8 to 10 hours. 

Although 200 mg twice a day might be effective against moderate anxiety symptoms, severe anxiety may require higher doses, around 600 to 800 mg per day divided into 200-mg increments every 3 to 4 hours.

If you're considering taking L-theanine for anxiety, we recommend beginning with a dose between 50-100 mg. Then, you can gradually increase it to 400 mg.

Moreover, in combination with 30-100 mg caffeine, L-theanine (12.5-100 mg) improves visual information processing, reduces mental fatigue, increases reaction time and working memory, alertness, and eases headaches. 

On the other hand, ADHD and anxiety coexist in many young people in the United States. The oral consumption of 400 mg of L-theanine promoted better rest and encouraged attention and focus without showing adverse side effects. It is possibly safe for children to take this supplement but under the supervision of a physician. 

Due to the insufficient information about the use of Theanine during pregnancy and breastfeeding, we recommend avoiding its consumption for safety. 


Taking L-Theanine for anxiety works by decreasing “excitatory” brain chemicals that contribute to stress and anxiety while increasing brain chemicals that encourage a sense of calm and promote cognition and selective attention. This water-soluble, non-protein amino acid has been beneficial for many people suffering from generalized anxiety disorders and acute anxiety.  

Research has proved that this non-protein amino acid is generally well-tolerated and has no severe side effects. Nonetheless, these promising findings need to be confirmed. Because there isn't conclusive research, it’s best to consult your medical provider which is the best L-theanine dosage for you before taking any supplement.