What is “theanine” in black and green tea, which is said to “improve concentration”?


Hello, this is Santoshi. What is your favorite beverage to drink during work?

I often drink hot tea or coffee.

I especially drink black tea.

When I drink a lot of coffee, I get a stomach ache…I wonder if there is something I can do about it. I would like to introduce an article I found that an ingredient in tea called “theanine” is very useful for work.

Theanine is an amino acid that is a flavor component of tea, and is found in green tea, black tea, and some mushrooms. This article summarizes the results of animal experiments and small-scale studies conducted to date on what exactly “theanine” is, which is said to affect people’s mood and stress levels by influencing dopamine and serotonin, which are related to mood, sleep, and emotions, as well as the stress hormone cortisol.


L-theanine: Benefits, risks, sources, and dosage


Theanine is a natural, natural, and effective stress reliever.

1: Improving Concentration

The group that took 100 mg of theanine made fewer mistakes on tasks that required concentration than the placebo group, and when combined with caffeine, it similarly increased a person’s ability to concentrate.

2: Better sleep quality

Consuming theanine before bed is said to help people relax, fall asleep more easily, and get deeper sleep; in a 2018 study, subjects with anxiety disorders and using antidepressants became more satisfied with their sleep state after taking 450-900 mg of theanine daily for eight weeks They were more satisfied with their sleep state. It is important to note, however, that anxiety and insomnia themselves were not resolved. 3: Relaxation
A 2007 study showed that theanine consumption leads to a decrease in heart rate, and ingesting theanine, which is found in black and green tea, is associated with relaxation.

3: Increased cognitive performance

In 2016, a number of previously published studies were re-evaluated and concluded that theanine has positive effects on mental and physical health. According to researchers, theanine has neuroprotective effects and improves brain function. By itself, theanine improves attention and response time, but when combined with caffeine, it further improves multiple skills and alertness.
However, not all studies have found theanine to be effective in improving cognitive function, so more high-quality research is needed to confirm its effectiveness.

4: Weight loss

Several diet studies have shown that replacing snacks with low-calorie hot beverages such as green tea results in weight loss. Since studies have shown that flavorful ingredients suppress human appetite, it is possible that theanine, a flavorful ingredient, may help with weight loss.

5: Boosts the immune system

Several studies have shown that theanine may boost the immune system, and it is possible that theanine intake may reduce the risk of catching colds and influenza.

6: Inhibition of blood pressure elevation

A 2012 study showed that theanine intake in situations of physical and mental stress can reduce elevated blood pressure. This study found that theanine’s effect was greater than that of caffeine.

7: Aids Cancer Drugs

Several animal studies suggest that theanine may increase the effectiveness of a cancer drug called doxorubicin. However, this data is not immediately applicable to humans, as animals and humans respond differently in many ways. Scientists also note that many of the theanine studies have been small-scale, with small samples, and further large-scale, high-quality studies are needed to understand the relationship between these scientific substances.

The U.S. Food and Drug Administration (FDA) classifies theanine as “generally recognized as safe,” which basically means that it is safe to consume with no side effects. However, if you are taking some medications, such as high blood pressure, ADHD medications, or supplements containing caffeine, you should consult your doctor, and it should not be used by pregnant or nursing women.