What is L-Theanine?
L-Theanine is a fascinating and relatively rare amino acid, primarily known for its remarkable, relaxing and stress-reducing properties . This natural compound has the ability to put the body and mind into a state of calm and relaxation, without causing drowsiness or lethargy . The special thing about L-Theanine is that it can cross the blood-brain barrier and thus acts directly in the brain, where it influences the production of neurotransmitters and promotes alpha brain wave activity.
Interestingly, this special 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 highlighted the numerous health benefits of L-Theanine and established it as a promising natural substance for overall well-being and health. Where does L-Theanine occur? As already mentioned, L-Theanine is primarily found in green tea, but also in smaller amounts in other types of tea and even in some species of mushrooms. Table 1: The average molecular content of various types of tea was analyzed in a Hungarian publication.
| Tea type | 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 |
Did you know: 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 had only 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 Effects – What Benefits Does L-Theanine Offer the Human Body?
Similar to EGCG L-Theanine offers the body a particularly wide range of potential health effects:
Relaxation and Stress Reduction
L-Theanine can increase alpha brain waves, thereby inducing a feeling of relaxation without causing drowsiness. In another study, research was conducted 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 contributes to the reduction of stress and anxiety .
Improvement of cognitive performance
A study has shown that L-Theanine in combination with small amounts of Caffeine can improve attention and concentration. In a double-blind, randomized, placebo-controlled research study (highest evidence), the effects of the vital substance on cognitive functions of healthy adults aged between 50 and 69 years were investigated. It was found that a single dose of L-Theanine improved attention and working memory, suggesting that it may contribute to the improvement of overall cognitive abilities .
Support for the Immune System
There is also evidence that L-Theanine can strengthen the immune system by promoting the production of antibodies and other immune cells. For example, a research study found that the molecule could contribute to reducing upper respiratory infections.
In a randomized, double-blind, placebo-controlled study with 200 healthcare workers, it was investigated whether catechins and theanine from green tea can prevent a flu infection. The participants took 6 capsules per day, which contained a total of 378 mg of catechins (of which 270 mg EGCG) and 210 mg of theanine.The results showed that the frequency of flu infections in the group taking catechin/theanine capsules was significantly lower than in the placebo group, indicating that green tea catechins and theanine may contribute to the prevention of a flu infection.
