What is l theanine good for? Tea drinkers around the world credit this humble amino acid with everything from enhanced mood to improved creativity, but what is the science behind this?
In this article, we are going to explain what is l-theanine and what is it good for. We’ll take a look at some research to find out what’s behind the legendary “calm alert” feeling tea has become famous for.
Let’s get brewing!
what is l-theanine and what is it good for
To kick things off, what is l-theanine and what is it good for? L-theanine is an amino acid that is primarily found in the tea plant. It is used by the tea plant as a nutrient delivery system, to transport nitrogen from the soil to the tea leaves where it can support growth.
The flavor of l theanine
Because l theanine is an amino acid, it produces a rich and savory flavor in the tea. This is really desirable when it comes to Japanese green tea, particularly with more luxury tea like gyokuro and matcha.
But what is l theanine good for other than flavor? That we’ll discuss in the next section when we review the health benefits.
Increasing the levels of l theanine
If a farmer wants to increase the theanine content of a tea (and therefore its sweet-savory flavor) he can do this in two ways: fertilization and shading. By supplying more nitrogen to the soil in the form of fertilizer, the tea plant will produce more theanine in order to deliver this nitrogen to the leaves.
Also, the farmer can shade the tea plants, which will allow them to retain more of their theanine. When the tea plant is exposed to sunlight, it converts theanine into bitter tasting catechins. To produce sweeter teas like gyokuro, the farmer can cut them off from sunlight for the final days before the harvest to reduce their bitterness.
What is l-theanine good for health wise?
So what is l-theanine good for when it comes to health benefits? L-theanine is not as well studied as caffeine, for example, but there are a few studies that have shown promising results when it comes to cognition, stress reduction and even sleep.
Stress and Anxiety Reduction
When asking what is L-theanine good for, one of the strongest science-backed answers is stress reduction. In a randomized, double-blind, placebo-controlled clinical trial published in Nutrients (2019), 30 healthy adults who consumed 200 mg of L-theanine daily for four weeks showed significantly lower stress, anxiety, and depression scores compared with placebo (Hidese et al.).
Improved Sleep Quality
L-theanine may also show an improvement in sleep quality, due to the relaxing effect it has. A placebo-controlled clinical study in Asia Pacific Journal of Clinical Nutrition (2011) found that boys with ADHD who took 400 mg of L-theanine daily for six weeks experienced significantly better sleep efficiency and fewer nighttime disturbances compared to placebo (Lyon et al.). This supports what is L-theanine good for when it comes to calming the mind before sleep.
Focus and Cognitive Performance
Research also suggests that l theanine may be good for enhanced attention and cognitive performance, particularly under mentally demanding conditions. A double-blind study published in Nutritional Neuroscience (2008) showed that adults given L-theanine (100 mg) combined with caffeine performed better on attention-switching and alertness tasks than those given placebo (Haskell et al.).
It’s important to note here that these results are only strong when caffeine is paired with l theanine, as these two tend to work in synergy with eachother.
Relaxation Without Drowsiness
For those wondering what is L-theanine good for during the day, research shows it promotes relaxation without causing drowsiness. In a controlled human study published in Biological Psychology (2008), participants who consumed 200 mg of L-theanine exhibited increased alpha brain wave activity compared with placebo (Nobre et al.).
Alpha brainwave activity is usually associated with a calm alert sensation, which is good for creativity, meditation and flow state work.
Executive Function and Verbal Fluency
Emerging research indicates that what is L-theanine good for may also include support for higher-level cognitive functions. In the same randomized controlled trial published in Nutrients (2019), participants taking L-theanine showed significant improvements in executive function and verbal fluency compared with placebo (Hidese et al.).
Teas highest in l theanine
Now that we’ve learned what is l theanine good for, you’re probably itching to get your hands on some high theanine green teas. Here, we are looking for first harvest, shaded teas that are made from the young sprouts of the tea plant. These will not only be high in theanine, but also in caffeine as well.
Gyokuro
Gyokuro is an all-star when it comes to l theanine. Not only is this tea made from the younger, more nutrient dense tea leaves, it’s shaded for 3 weeks or more before the harvest. This allows the farmer to maximize the l-theanine content of the crop and produce a smooth, savory green tea.
Matcha
When in doubt, drink some matcha! Unlike other teas which are infused into water, matcha is ground into a powder and mixed directly into water. This means you are consuming the entire leaf, along with all its benefits. You’ll get more nutrients per sip of this tea than with any other!
Kabusecha
Another long-shaded tea that doesn’t get as much credit as gyokuro and matcha is kabusecha. This tea is shaded for between 10-20 days which makes it one step down from gyokuro. Rather than this rich, brothy flavor, you get a light sweetness and hint of seaweed.
What is l theanine good for - the final verdict
So what is l-theanine good for? The strongest data shows that l-theanine can lead to reduced stress and improved sleep. There are also studies that have demonstrated an improvement in overall mood and focus, however when it comes to focus the results are better when compared with caffeine.
Theanine is believed to buffer some of the negative side effects of caffeine, like the jitters or nervousness. The good news is, high caffeine teas like matcha and gyokuro also tend to be high in theanine as well!
