Subscribe TODAY and get your second month FREE!

Shopping Cart






{item.line_price | money}


{cart.total_price | money}


Your cart is empty

Everything You Need to Know About L-Theanine

If you’re getting serious about stress management, one ingredient you need to know about is L-Theanine. L-theanine is one of the active and botanical natural ingredients included in R3SET’s signature stress-support  formula, and we love it because of its benefits for mood regulation, sleep, and more. 

In this post, we’ll be discussing L-theanine in depth. Here, you’ll find everything you need to know about this powerful stress-support ingredient – its benefits, tips for use, warnings and safety advice, and more.

Let’s get started!

L-Theanine: A Quick Introduction 

L-Theanine (also known as suntheanine or N-ethyl-L-glutamine) is an amino acid. Amino acids are compounds made up of carbon, oxygen, nitrogen, and hydrogen, along with other elements. L-Theanine is structurally similar to GABA and glutamate, two neurotransmitters that it produces. 

Your body needs nine essential amino acids to support your overall health, but other amino acids can be beneficial as well. Your body cannot produce amino acids on its own, so it needs to get these important compounds from foods.

Amino Acids Explained 

Amino acids are the building blocks of proteins. Protein is one of the three essential macronutrients that your body gets from food – carbohydrates and fat are the other two. 

The nine essential amino acids, which are all found in many protein-rich foods, are the following:

  1. Phenylalanine
  2. Valine
  3. Threonine
  4. Tryptophan
  5. Methionine
  6. Leucine
  7. Isoleucine
  8. Lysine
  9. Histidine

Each of these nine essential amino acids plays specific roles within your body, and you need all of them for your overall health. However, the nine essential amino acids are far from the only organic compounds you can get from foods and drinks. 

L-Theanine, which is considered a non-essential amino acid, is naturally found in green tea, black tea, and several mushrooms. It's called a unique amino acid because of its exclusivity to tea leaves (camellia sinensis) and mushrooms. 

You can also take isolated L-Theanine as a supplement for improved sleep quality*. L-Theanine can also be used in place of caffeine to help boost focus and reaction times. 

Since your body cannot produce amino acids on its own, you won’t be able to get L-Theanine by sitting around and waiting for it to spontaneously generate. Instead, you can reap the benefits of this amino acid through tea consumption (or eating mushrooms), and including R3SET dietary supplements in your daily regimen.

L-Theanine’s Benefits For Stress Reduction 

Research has shown that L-Theanine may be linked to the production of specific chemicals within your brain, including the neurotransmitters dopamine, serotonin, and cortisol. Dopamine and serotonin are associated with pleasure and contentment, while cortisol helps you manage stress and is released as part of your body’s natural stress response.

When you are stressed out, your nervous,endocrine and immune systems are affected. Stress can also raise your blood pressure and your heart rate. This means your body is releasing chemicals and hormones that can make you feel on edge, anxious, and generally thrown off balance. 

If you are dealing with everyday stress and feeling a little restless, L-Theanine may be a helpful compound to include in your daily routine. However, it’s important to note that this ingredient is far from a magical cure, especially just on its own. 

While it can provide a helpful mental boost, L-Theanine can only complement a well-rounded stress-supporting regimen. To maximize your resistance against stress, make sure to put other beneficial habits into practice, such as mediation, exercise, and getting plenty of sleep.

Can L-Theanine Replace Prescription Anxiety Medication? 

While the two terms are often used interchangeably, there are a few key differences between stress and anxiety. 

The primary distinction is that chronic anxiety is a diagnosable mental health disorder– this is known as generalized anxiety disorder. Many people who suffer from generalized anxiety disorder need to manage their symptoms using prescription anti-anxiety medication. Other treatment methods, such as counseling, can also be very helpful.

For someone taking medication for anxiety, it’s essential to never make changes to your medication regimen without consulting a healthcare professional. Thus, if you are considering making L-Theanine or other dietary supplements part of your daily routine and are taking any prescription medication, it’s important to first seek medical advice from your healthcare provider and let them know that you are planning to add the supplement to your anti-stress regimen. 

L-Theanine is considered safe by the FDA, but it is still important to consider that certain medications can have drug interactions with supplements, even including natural ones like L-Theanine. That means that you may not be able to use L-Theanine and take prescription anxiety medication at the same time. In addition, If you take medication to treat your anxiety, quitting cold turkey is never a good idea – you can end up experiencing severe withdrawal symptoms, which can make your anxiety worse.

So, what’s the bottom line? If you take prescription medication, always talk to your doctor before trying L-Theanine. While this amino acid can have benefits for someone dealing with everyday stress, it is not a replacement for prescription anti-anxiety medication. 

If you have questions about any supplements or natural ingredients, make sure to ask your doctor for advice.

Does L-Theanine Have Any Side Effects?

The primary research regarding L-Theanine’s potential side effects is related to the consumption of the compound in tea. As you can imagine, drinking too much tea is associated with side effects like headaches, irritability, and nausea. However, you’re much less likely to experience these symptoms when you take the proper dosage of L-Theanine as a supplement or drink moderate amounts of green or black tea. 

However, as previously mentioned, L-Theanine has the potential to be unsuitable for someone taking prescription medication. While the interaction between your medication and L-Theanine may not cause noticeable side effects, it might counteract the effectiveness of both your medication and your supplements.

Overall, L-Theanine is a generally safe supplement. As long as you don’t drink cup after cup of tea, you are unlikely to experience side effects related to too much tea. However, it bears repeating that you should always talk to your doctor if you are unsure if L-Theanine is right for you. 

How and When Should I Take L-Theanine? 

As you’ve learned, L-Theanine is found in tea, but it can also be taken as a standalone supplement, or in conjunction with other natural stress-fighting ingredients. There are several ways you can include L-Theanine in your daily routine, including the following:

  • Drink green tea. While L-Theanine is found in both green and black tea, the former generally has lower caffeine content than the latter. This makes green tea a great choice for anyone trying to limit their caffeine intake for the sake of better stress management. Green tea also has antioxidants (catechins) for an added health benefit! A few cups of green tea daily will give you a small caffeine boost, improve cognition, and provide you with some L-Theanine to boot.
  • Take an L-Theanine supplement. R3SET’s Calm formula includes L-theanine derived from green tea, which can help to ease stress and boost your focus throughout the day*.
  • Eat mushrooms. Some mushrooms – specifically boletus edulis, also known as the penny bun mushroom – contain L-theanine. Mushrooms are also an excellent source of vitamin D and other important nutrients. 

The Best Time to Take L-Theanine 

L-Theanine can be taken at any time during the day to help you calm down. However, it’s important to note that the amino acid’s effects are usually not immediate – L-Theanine usually takes about 30 to 40 minutes to produce results. That means it may be a good idea to take the supplement about an hour before starting your workday if you tend to feel stressed and jittery when daily tasks begin and want to improve cognitive function without the use of caffeine. 

In addition, L-Theanine is a suitable supplement to take before bed. Although the amino acid is found in some caffeinated drinks, the compound itself does not have a stimulating effect that will keep you awake. However, if you are getting your L-Theanine from caffeinated beverages like green or black tea, ingestion is best in the morning or early afternoon rather than enjoying them before bed.

L-Theanine Dosages 

There are no defined doses for L-Theanine. The typical dose size for L-Theanine is between 50 and 200 mg. For reference, 1 gram of Matcha contains 19.5 milligrams of L-Theanine, so a cup of Matcha (2 grams) should contain less than 40 milligrams. . Matcha is a highly concentrated green tea powder that has a distinct grassy flavor – it’s also an excellent source of antioxidants and L-Theanine. However, it’s best to enjoy matcha in moderation, since this form of green tea is higher in caffeine. 

If you want to increase your overall focus and energy, swapping out your morning coffee for green tea is a great idea. A standard cup of green tea contains over 6.5 mg per gram of tea, and most cups of tea are made with at least 3 grams of leaves. That means you’ll be getting around 20 mg of L-theanine from each cup of green tea you drink! 

In addition, if you are taking L-theanine as a standalone supplement, it’s best to stay within the 50-200 mg range for each dosage. The effects of L-Theanine can last for several hours, so you shouldn’t need to take the supplement more than once per day. 

Overall, taking an L-Theanine supplement is a simple, practical way to maintain all-day focus and mental energy as you work and conquer your daily tasks.

Other Benefits of L-Theanine 

One of the other potential benefits of L-theanine is increased focus and attention. If you struggle to stay on task throughout the day, taking L-theanine as a supplement may be helpful to you. We’ve included L-theanine in our Calm supplements, which are designed to keep you alert, focused, and at ease as you take on the tasks and responsibilities of the day. 

The Calm formula is designed to give you some of the same perks as your morning cup of coffee – increased focus and mental energy. However, while drinking coffee can provide you with antioxidants and may help you focus, it also comes with some major cons. Coffee is a mild diuretic, meaning it can make you dehydrated if you consume too much without drinking enough water. In addition, the jolt of energy provided by caffeine often leads to a crash after a few hours. 

We formulated our Calm supplements with L-theanine to offer you the boost in focus and attention that you’d get from coffee – without the energy crash*. However, some research has been done to indicate that L-theanine and caffeine can actually pair well.  

One 2012 study assessed the effects of combining L-theanine with caffeine to increase focus and attention. While further research needs to be conducted to reach a more definitive conclusion, it seems that L-theanine and caffeine are complementary to each other.

In addition, a 2018 study on L-theanine found that many participants reported that they were more satisfied with their quality of sleep after taking several hundred milligrams of the supplement for 8 weeks. As is the case with the relationship between L-theanine and caffeine, further research needs to be conducted before L-theanine’s effect on sleep can be fully understood. However, there are plenty of good reasons to supplement with L-theanine for sleep – it’s natural, has little potential for side effects, and is considered safe by the FDA


L-Theanine is a great ingredient to include in your daily routine to promote increased focus and mental energy, as well as better sleep. 

If you’re looking for an ideal source of L-theanine to include in your supplement regimen, make sure to check out R3SET’s Calm and Unwind capsules. Our supplements are formulated with  active botanical ingredients that provide powerful stress-support*. If you need an extra line of defense against life’s stresses, Calm and Unwind may be perfect for you. 

In addition, if you want to learn more about stress reduction, the causes of stress, and much more, make sure to check out the R3SET blog. There, you’ll find plenty of helpful articles about the ingredients included in our formulas, as well as tips for reducing everyday stress and anxiety in your life.

*These statements have not been evaluated by the Food and Drug Administration (FDA). This product is not intended to diagnose, treat, cure or prevent any disease



Sign Up Complete!

You have successfully joined our mailing list.