What is L-Theanine?
L-Theanine is a fascinating and relatively rare amino acid that is best known for its remarkable, relaxing and stress-reducing properties . This natural compound has the ability to bring the body and mind into a state of calm and relaxation without causing drowsiness or dizziness . The special thing about L-theanine is that it can cross the blood-brain barrier and therefore acts directly in the brain, where it influences the production of neurotransmitters and promotes alpha brain wave activity.
Interestingly, the particular amino acid has a chemical structure similar to glutamic acid, an amino acid that functions as a neurotransmitter in the brain. This similarity could be one of the reasons for the diverse effects of the vital substance on the nervous system and cognitive performance. In recent years, scientific research has increasingly brought to light the numerous health benefits of L-theanine, establishing it as a promising natural substance for overall well-being and health.
Where is L-theanine found?
As already mentioned, L-theanine is mainly found in green tea , but also in smaller amounts in other types of tea and even in some species of fungi.
Table 1: The average molecule content of various types of tea was analyzed in a Hungarian publication.
| Type of tea | L-theanine content |
| Green tea | 6.56 mg/g |
| White tea | 6.26 mg/g |
| Oolong tea | 6.09 mg/g |
| Black tea | 5.13 mg/g |
Worth knowing: The L-theanine content varies enormously from tea to tea. While a Korean green tea contained 10.93 mg/g, a Chinese green sencha tea only had 2.65 mg/g. This is one of the reasons why many people prefer to consume the molecule in the form of a dietary supplement.
L-Theanine Effect – What benefits does L-Theanine offer the human body?
Similar to EGCG L-theanine offers the body a particularly wide variety of potential health effects:
Relaxation and stress reduction
L-Theanine can increase alpha brain waves, thereby producing a feeling of relaxation without causing drowsiness. Another study examined research on the effects of L-theanine on stress and anxiety in humans. They analyzed five high-quality studies with 104 participants. Four of these studies found that taking 200 to 400 mg of L-theanine per day helped reduce stress and anxiety .
Improvement of cognitive performance
A study has shown that L-theanine in combination with small amounts caffeine can improve attention and concentration. In a double-blind, randomized, placebo-controlled research study (highest evidence), the effects of the vital substance on the cognitive functions of healthy adults between 50 and 69 years of age were examined. A single dose of L-theanine was found to improve attention and working memory, suggesting that it may help improve general cognitive abilities can contribute.
Immune system support
There is also evidence that L-theanine can strengthen the immune system by promoting the production of antibodies and other immune cells. For example, one research paper found that the molecule could help reduce upper respiratory tract infections.
A randomized, double-blind, placebo-controlled study involving 200 healthcare workers examined whether catechins and theanine from green tea could prevent influenza infection. The subjects swallowed 6 capsules per day, which contained a total of 378 mg catechins (of which 270 mg EGCG) and 210 mg theanine. The results showed that the frequency of influenza infections in the group taking catechin/theanine capsules was significantly lower than in the placebo group, which indicates suggests that green tea catechins and theanine may help prevent flu infection.
