L-Theanine Nootropic Benefits (+ Side Effects and Dosage Info)

L-Theanine Nootropic Benefits (+ Side Effects and Dosage Info) - Lucid™

You may be familiar with L-theanine–the amino acid derived from tea leaves that are added to nearly every energy-boosting drink and supplement on the market. You may even have the impression that L-theanine is an energy supplement, but that's not exactly the truth. L-theanine does pair well with caffeine–but there's so much more to L-theanine nootropic benefits that you should know. 

If you're curious about trying L-theanine for yourself, let us uncover some truths about L-theanine's benefits, uses, and side effects to help you make up your mind:

Key Takeaways

L-theanine is an amino acid that may calm the nervous system and support brain health. 

Research is limited, but many people believe that L-theanine supplementation can improve cognitive function, concentration, and working memory. 

L-theanine pairs well with caffeine and other nootropics to create a full-coverage brain-boosting routine. 

What is L-Theanine?

L-theanine is an amino acid that's abundant in tea leaves. It can also be found in some foods and especially in most varieties of edible mushrooms. It's one of the most common forms of supplemental theanine, an amino acid that's not produced naturally by the body, meaning we need to get it from our diets. 

In the body, L-theanine acts similarly to glutamate, an amino acid that helps to regulate the nervous system and send nerve signals through the brain. Some evidence suggests that theanine can help to promote calmness within the nervous system and may help improve concentration. It may also impact the production and uptake of essential neurochemicals, like GABA, dopamine, and serotonin, which may lend an explanation to its potential benefits for sleep or reducing anxiety. 

In fact, it may have several nootropics benefits that are noteworthy. Let’s dig into what that really means:

What are nootropics?

We mentioned that nootropics are a class of substances, sometimes called “smart drugs,” that are known to enhance cognitive function, but let’s dive deeper. Nootropics are substances that alter neuronal production or change the way that the nervous system uses different neurochemicals. 

Most often, nootropics work by altering the production or uptake of dopamine, serotonin, GABA, or norepinephrine. These neurotransmitters help to regulate all functions, including appetite, focus, energy, sleep, mood, and so much more. 

There are natural and synthetic nootropics, including prescription nootropic medications like Adderall. However, many synthetic nootropics, whether prescription of not, come with unwanted side effects and are potentially habit-forming. For that reason, it may be a good idea to explore the natural nootropics first.

L-Theanine Nootropic Benefits (and Research)

L-theanine research is currently limited, but some there are some areas of interest, including the following:

Improved Concentration

According to a 2012 study, a combination of L-theanine and caffeine may be responsible for the improved concentration abilities associated with drinking various green and black tea varieties. In this study, subjects took 100 milligrams of L-theanine alongside 50 milligrams of naturally occurring caffeine. Subjects were recorded to make fewer errors while under pressure compared to the placebo group. 

This isn't the only call for L-theanine to be paired with caffeine. In fact, the two are quite the dynamic duo. Take a look:

Synergizing with Caffeine

Research shows that L-theanine may help to reduce some of the most common side effects associated with caffeine use, like increased blood pressure, anxiety, and jitteriness. 

One study found that L-theanine may help to prevent the dilation of blood vessels after consuming caffeine, effectively reducing its impact on blood pressure and anxiety levels. Another study found that L-theanine can improve and protect slow-wave sleep cycles against the effects of caffeine, which may help to prevent sleep caffeine-associated disruptions. 

Plus, research shows that the two may pair together to offer significant benefits, like improved reaction times, improved word recognition, improved attention, and improved ability to switch between tasks, with greater accuracy upon completion. With all these potential benefits at hand, taking L-theanine with our daily caffeine dose is a no-brainer. 

Read our article "How Much L-theanine to Take with Coffee" to learn more.

Enhancing Sleep

Researchers also believe that L-theanine may help to improve sleep. Specifically, it can help to increase slow-wave sleep, the portion of sleep that helps us feel more rested.

According to a 2018 study, participants experienced better sleep after taking up to 900 milligrams of L-theanine daily for up to 8 weeks. It's noteworthy to mention that many of the subjects in this study were known to suffer from anxiety or depression and some were taking medications to treat these mental health conditions. 

Ultimately, researchers believe that L-theanine may help people fall asleep more easily and may improve the quality of sleep overall. 


Hand in hand with its ability to improve sleep is its benefits for promoting relaxation. According to an extensive 2016 review, naturally occurring L-theanine in tea may help people relax by lowering their resting heart rate. It’s unknown how this benefit may be clinically applied, but it’s another reason why L-theanine may pair well with caffeine. 

Improved cognitive functions

The same review above mentions L-theanine in many lights–one of which is its ability to improve cognitive performance. More specifically, it states that L-theanine may be able to  improve focus, reaction times, and alertness. It’s important to note that in this research L-theanine was combined with the naturally occurring caffeine in either black or green tea. 

Immune boosting

The 2016 review also mentioned that L-theanine may help to boost immunity by increasing the body’s ability to fight off common illnesses like influenza or the common cold. 

How to Use L-Theanine as a Nootropic

L-theanine can be consumed in dietary form, but if you want to get the most of L-theanine’s nootropic benefits, you should probably consider an L-theanine supplement. 

Of course, supplements in the U.S. are not standardized and are not regulated as harshly as prescription medications, so it’s important that you understand how to choose an L-theanine supplement and how to use it correctly. 

Here’s what you need to consider: 

Quality and Source

As with all supplements, choosing a high-quality L-theanine supplement is crucial. The easiest way to do this is to look for a company that uses a third-party testing process to ensure quality and manufactures their product in cGMP-compliant facilities. 

Forms of L-theanine

L-theanine is the most common form of theanine and is available in several different dosing forms. However, capsules are the most common way that L-theanine is sold and consumed. You can also find L-theanine powder, which is an appropriate dosing method for anyone who needs more precise control over their L-theanine dose. 

If you wish, you can try to get your L-theanine from whole food sources, but you may need to incorporate it from several different sources to get enough to experience nootropic benefits. Green tea and dietary mushrooms are both good options. 

Many people prefer to take L-theanine with other nootropic and adaptogenic herbs and supplements designed to support brain health and general wellness, so you may prefer to look for a nootropic stack, or a combination of nootropic supplements designed to work synergistically together. 

When to Take L-Theanine Nootropics

When using L-theanine to boost concentration and relieve stress throughout the day, it’s best to take it in the morning. Ideally, you should take L-theanine with your coffee, approximately half an hour before breakfast. 

For those who wish to take L-theanine for sleep support, thirty minutes before bed is a better option. 

Keep in mind that you may need to take L-theanine daily for 1-2 weeks before you notice full benefits. 

L-Theanine Dosage

In research, the daily dosage of L-theanine ranges from 100 milligrams to 400 milligrams. Typically, doses between 150 milligrams and 250 milligrams are appropriate. The L-theanine dosage needed is also affected by the other nootropics in your wellness routine, as many nootropics have overlapping effects. 

If you are incorporating L-theanine on its own, you may start with 100 milligram doses. If you plan to use a wellness stack that contains L-theanine, follow the dosage instructions given. 

Because L-theanine is sold as a supplement in the U.S., products are not standardized and there are no dosage recommendations given. Always read the product you buy carefully to ensure you understand the potency and talk to your doctor before using L-theanine, especially if you take prescription medications or suffer from a serious or chronic condition.

Are L-Theanine Nootropics Safe?

The FDA has classified L-theanine as GRAS, or “generally recognized as safe.” This means that L-theanine is believed to be safe when used according to package directions, assuming that the product is products and labeled according to the FDA’s Good Marketing Practice guidelines. 

In fact, there are no known side effects associated with L-theanine. Still, you may be at risk when taking L-theanine if you meet ank of the following conditions:

  • You are pregnant or breastfeeding
  • You take medications for high or low blood pressure
  • You take prescription stimulants, like ADHD medications
  • You use street drugs
  • You contain caffeine in amounts that exceed general recommendations (400 milligrams per day)

As always, you should talk to your doctor before adding a new supplement to your wellness routine. 

Enjoy L-Theanine in a Nootropic Stack

If you’re looking to take advantage of an L-theanine nootropic blend (and enjoy the convenience of a pre-made, full-coverage nootropic stack) check out our Lucid nootropic stack, which contains:

Want to learn more? Read “Why We Chose Our Ingredients? What’s in a Lucid Stack?” Or, check out one of our three flavor varieties:


  1. “Assessing the effects of caffeine and theanine on the maintenance of vigilance during a sustained attention task” https://pubmed.ncbi.nlm.nih.gov/22326943/
  2. “L-theanine in the adjunctive treatment of generalized anxiety disorder: A double-blind, randomised, placebo-controlled trial” https://pubmed.ncbi.nlm.nih.gov/30580081/
  3. “L-Theanine as a Functional Food Additive: Its Role in Disease Prevention and Health Promotion” https://www.mdpi.com/2306-5710/2/2/13/htm
  4. “GRN No. 209: L-theanine”https://www.cfsanappsexternal.fda.gov/scripts/fdcc/index.cfm?set=GrASNotices&id=209 

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