L-Theanine, the amino acid of tranquility and concentration

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L-Theanine is an amino acid that was first identified in tea leaves, just a few decades ago. Several studies have shown that it promotes relaxation without causing drowsiness, facilitating anxiety and it seems to have a positive effect even in the concentration.

Sources and mode of action of theanine

L-theanine is an amino acid that is unusual in the diet, as it belongs to the non-essential amino acids and it is not particularly common. L-Theanine has a chemical structure similar to glutamine and some neurotransmitters produced by it (GABA and glutamate), acts on the brain and transmits nerve messages in a similar way. It is more commonly found in tea leaves, while also in certain types of mushrooms. The most common source of L-theanine is the leaves of camellia sinensis and it accounts for 50% of the total amino acids in the tea.


Properties and actions

Relaxation – tranquility

L-Theanine is a relaxing agent that does not cause sedation or drowsiness. It is involved in reducing the perception of anxiety and in slightly improving attention. The relaxing effect of l-theanine is attributed to the increase in α-waves in the brain, which are associated with relaxation. It has also been shown to reduce the heart rate of rest. Its effect occurs within 30-60 minutes.

Insomnia – Quality of sleep

Although L-theanine does not appear to cause drowsiness, it can help in insomnia. Some research have shown that L-theanine could be beneficial in improving the quality of sleep in people with attention deficit hyperactivity disorder (ADHD). The duration and latency of sleeping are not affected.

Attention and concentration

In addition to relaxation, elevated α-waves are associated with selective alertness, brain stimulation, and mental alertness, especially in people with high levels of anxiety. A similar benefit was also observed in people suffering from mild cognitive impairment.


L Theanine appears to be beneficial even in anxiety situations. Studies have shown that supplementation with l-theanine reduces symptoms of anxiety in people who experience stress or suffer from schizophrenia.

Blood pressure

L-thetaine may be beneficial for those who have increased blood pressure in stressful situations. A recent study showed that L-theanine contributed to controlling blood pressure in people who had high blood pressure after some mental work.


Dose and interactions

For sleep, rest and stress, it is advised to take l-Theanine for 3 weeks at doses of 100-400 mg / day. It can be combined with caffeine to increase the concentration (12-100 mg L-theanine and 30-100 mg caffeine). There are no side effects from taking L-theanine and it is considered as a safe dietary supplement. Even in high doses no toxicity has been observed. It is recommended not to be taken by people undergoing chemotherapy or taking anti-hypertensive or stimulant medications.


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