What is Theanine?

Work, school, family, the economy; People say every one of these things is stressing them to the max and they’re looking for some natural stress relief. For this reason, theanine has come to prominence. So what is theanine and can it help us to relax naturally? 


What is L-Theanine?

Theanine molecule infographic

Theanine is an amino acid that comes in two forms L-theanine and D-theanine. It’s typically found in tea and to a lesser extent some mushrooms including maitake, hedgehog and button mushrooms. 

In the body, it can act like glutamate, a different amino acid which helps to transmit nerve impulses in the brain. In some circles, glutamate is even referred to as the master neurotransmitter for its effects on memory, cognition and mood regulation. 


Uses and Benefits


Stress and Anxiety Relief

Woman meditating to reduce stress

How do you relax after a stressful day? Most people the world over will answer with a nice cup of tea. Well, the theanine tea contains might be why. Theanine acts on brain chemicals like GABA, dopamine and serotonin. As a result, people use it for stress relief, anxiety relief and overall mental wellness. 

In 2016 a review of 5 randomized controlled trials including 104 participants compared theanine to a placebo in 4 studies with 1 study comparing theanine to the anxiety medication alprazolam. The first four studies showed improvement while the study comparing theanine to the medication didn’t show drastic improvement in either the medication group nor the theanine group. 

A 2019 randomized-controlled trial of 30 participants pitted theanine against a placebo and the theanine group (self) reported decreased symptoms of stress, anxiety, depression and trouble sleeping. 


Better Mental Performance

Brain fog and a fleeting ability to focus have been increasing problems but some think theanine can help especially when paired with your morning coffee.  

A placebo-controlled study from 2010 found the combination of moderate levels of L-theanine (97 mg) and caffeine (40 mg) significantly improved accuracy during tasks, increased alertness and decreased tiredness. 


Better Sleep

This might seem to conflict with the last entry wherein studies showed increased alertness for those taking theanine. The Cleveland Clinic points out that the effect you get from theanine can depend on the time of day you take it, what you take it with and even person-to-person variation. 

If you’re struggling to get your Zs theanine has some potential to help. In studies that paired theanine with GABA, participants experienced better sleep quality and sleep duration. 

Why this combination? GABA, short for gamma-aminobutyric acid, is a chemical messenger that provides calming benefits. Glutamate, which theanine imitates, acts on GABA to control a number of bodily processes. 

If you decide to use theanine for sleep, experts recommend taking it late in the day and without caffeine. A supplement form of theanine might be ideal for this use but if you decide you want to get your theanine from tea, choose white tea as it will be lightest in caffeine. 


Theanine itself has generally been found to be safe in most situations.


The only caveat is for those who get their theanine from green tea for the following reasons. 


  • Great tea has a polyphenol EGCG that can decrease the effectiveness of some chemotherapy drugs. 
  • Green tea has caffeine so pregnant women will want to limit their intake. 
  • Excessive green tea intake can lead to upset stomach, nausea and irritability


Bottom Line

In short theanine is a specialized amino acid associated with a few different mental and cognitive health benefits. It’s naturally occurring and generally safe for most people. 


*These statements have not been evaluated by the Food and Drug Administration. Products are not intended to diagnose, treat, cure or prevent disease.