8 Best L Theanine Supplement: Complete Buyer's Guide ...

07 Oct.,2024

 

8 Best L Theanine Supplement: Complete Buyer's Guide ...

8 Best L Theanine Supplement: Complete Buyer's Guide For Fighting Anxiety

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Best L-Theanine Supplements

Do you often find yourself grappling with stress and anxiety and unsure which if supplements or herbs can help? The laundry list of L-Theanine brands make things even more difficult.

Luckily, I've personally tested tons of L Theanine products and can share my first hadn experience with use using them to help with stress, sleep and anxiety. Below are the 8 best L Theanine supplements on the market.

One thing before we get started: this website is reader-supported. I spend a lot of time personally evaluating, testing and reviewing each product on this list. When you buy through links on our site, I may earn an affiliate commission.

8 Best L Theanine Supplements

Best Overall: Sports Research Double Strength L-Theanine Supplement

Sports Research is my go-to brand for most supplements because I am a familiar with their quality and rigorous testing standards.

I wouldn't place too much into the 'double strength' mention on the bottle. Each serving (1 softgel) is 200 mg, which is a pretty standard dose from the brands I have tried.

But when it comes to quality and sourcing, Sports Research stands alone for two main reasons:

  1. They use Suntheanine, which is the specific type used in most research.
  2. The softgel is made from Organic ingredients (coconut oil, gelatin, beeswax).

Now when it comes to quality, brands can rant and rave with marketing speak all they want. What I love about Sports Research is that they back it up with independent, 3rd party testing.

The product is tested for GMO's using IGEN, which is an independent 3rd party testing program that verifies products are Non-GMO. They're also gluten free and cGMP compliant.

I found that a dose of 200 mg about 2 hours before bed helps me unwind after a long, stressful day. It also seems to help me sleep.

 

Runner Up: Thorne Theanine

Thorne is the runner up and could easily be in the number 1 spot. I've used it on and off for years and keep coming back to it because of the trust I have in their brand.

Each batch or Thorne goes through 4 rounds of independent, 3rd party testing to verify the potency. This product is cGMP compliant and certified through NSF Certified for Sport.

These certifications place tremendous trust in the brand because they test and verify exactly what is in the product.

It is no surprise that Thorne is trusted by many professional sports teams, doctors and the Mayo Clinic.

I appreciate that it is free from harmful additives, making it an excellent choice if you have a sensitive system.

The one thing with Thorne is that it's a bit more costly than some other products. But you can trust that you are getting a high quality L Theanine. I use it when work and life gets hectic as my wife and I have a little one running around and it is a godsend.

 

Best Dissolvable: EZ Melts Dissolvable L-Theanine

If you struggle with swallowing pills and the liquid is not your jam, why not try a dissolvable option?

This is where EZ Melts comes in. They are one of the only brand out there that makes fully dissolvable l-theanine. What does this mean?

You just place a tablet under your tongue and let it naturally dissolve. No water and no getting pills stuck in your throat.

The nice thing about dissolvable is that it gets right into your sublingual gland, which is located underneath your tongue.

This way it gets into your system faster than when it goes through your gut.

Ingredients: L-theanine - 200 mg Other ingredients: mannitol, modified cellulose, xylitol, natural flavor and color, citric acid, plant-based magnesium stearate, silica, plant-based stearic acid, monk fruit extract, and stevia leaf extract

The one thing to note is that there will be more ingredients to make the tablet taste decent. But it is a tradeoff worth considering if you can't do capsules.

I bought these for my wife and she had not problem taking it. They taste slightly sweet and melt quickly under your tongue.

 

Best L Theanine Gummies: Jarrow Formulas Theanine Gummies

I had to include some gummies on the list because they are fun and delicious. You'd be surprised at all the junk gummy products out there.

Most of the brands I tried and looked at use 'proprietary formulas' and don't even list the amount of theanine per gummy. If you ever see the words 'proprietary' run for the hills. It means the brand is disengenuous and not telling you how much is in the product because it is so little.

Anyways, these do have xylitol, which admittedly is not great. But it is the best option on the market for gummies.

Ingredients: L-theanine (Suntheanine), inulin, xylitol, water, pectin, malic acid, sodium citrate, natural flavors, sunflower oil, carnauba wax, stevia extract.

Yarrow is sugar free, gluten free and vegan friendly! Talk about a guilt free gummy.

What I love most is that each gummy has 100 mg of Suntheanine -- which is a high quality source that is used in most of the research on this compound.

I found the gummies themselves tasted pretty good. No bad aftertaste and a bit of an apple taste to them. They are not amazing, but if you want a real gummy, just buy a real gummy.

 

NOW Supplements, L-Theanine 200 mg

I have a deep history with NOW as one of the first supplements I ever used was their digestive enzymes back in . Now they're one of the most reputable brands in the space.

In my experience, this is one of the most cost effective brands on the list. But it is important to note that this cost does not sacrifice quality. NOW products are GMP certified and use strict testing standards on every batch.

As far as the supplement itself goes, you get 200 mg per serving. The other thing to note is that this product has added Inositol, which is crucial for maintaining artery health.

The thing I like about NOW L Theanine is how I can pair it with my morning coffee. 200 mg with some caffeine makes me productive without the caffeine crash in the afternoon.

It seems to balance the caffeine for me so that I am calm but focused.

 

Double Wood L-Theanine Supplement

Double Wood is a brand I keep seeing on Amazon. They have a great track record for making quality supplements at a good price.

With Double Wood you get 200 mg of pure L-Theanine in every single capsule (standard).

I appreciate the quality assurance with third party testing and the ability to track down each batch from the brand online. They make available each Certificate of Analysis (COA) so that you can verify what's in your batch.

It is both gluten free and non-gmo (although not 3rd party verified).

One thing I never thought I would admit is how L theanine helps me in social situations. I get social anxiety around big groups or meeting new people. I found taking 200-400 mg helps me ease into meeting new people.

 

Best Liquid: MaryRuth Organics L Theanine Liquid Drops

MaryRuth Organics is without a doubt the best liquid option on the market. I've tried a few and they taste awful.

I found MaryRuth to be great value for the money. This product performs exactly as described. No cheap frills, just a solid l theanine with 200 mg per serving.

It is easy to use the eye dropper for dosing. I found the taste is actually pretty good, which is kinda surprising to say about a supplement. To me it remind me of drinking flat sprite, in the best way possible.

Let's look at the ingredients: L Theanine, water, organic glycerin, citric acid, natural flavor, organic stevia leaf extract, potassium sorbate.

Nothing too unexpected on the list. I do appreciate the organic ingredients and the fact that it is sugar free and vegan.

A 2 ml serving gives you 200 mg. But you do need quite a few drops to get there (60 or so).

Try some today if you want a simple, liquid version.

 

Nature's Trove L-Theanine

Nature's Trove probably the best deal on the whole list in terms of cost per serving. You get 200 mg of L theanine for as low as $0.08 if you purchase in bulks (365 capsules).

What stands out to me is the fact that Nature's Trove is Non-GMO verified. This is exactly what you are looking for in a supplement like this. Something that verifies it is high quality and not full of fillers.

Ingredients: L-Theanine, Vegetable Capsule (Cellulose), Microcrystalline Cellulose, Silicon Dioxide, Vegetable Magnesium Stearate.

I typically combine this with L tryptophan and Magnesium L Threonate on nights when I can't sleep because of obtrusive thoughts. I find that combo one hour before bed gets me to sleep easy.

It is a subtle affect day to day -- almost barely noticeable. But taking it regularly does help with stress and anxiety as well.

The brand is packaged int he USA in a GMP and NSF certified facility. Try some today!

 

Things to Consider While Choosing an L-Theanine Supplement

Before buying L theanine, make sure you check the sourcing, extra ingredients, third party testing, where it's made and dosage recommendations. I also included my personal experience and feedback for each product on the list.

1. Sourcing and Type

Sourcing is crucial. You want to make sure any product you use tells you exactly how much and what type of theanine is in it. If you dig a bit deeper, you find products that are naturally made from green tea leaves.

Supplements labelled as "Suntheanine" in the ingredients panel are often considered high-quality as they imitate this natural process. Suntheanine is a patented ingredient that is used in many l theanine products.

It is a great source and has been used in many of the research studies on theanine.

2. Extra Ingredients

Ingredients to make the capsules are impossible to avoid. They have to use something to make it, after all. That being said, you should beware of extra ingredients like microcrystalline cellulose, hypromellose (vegetarian capsule) and silicon dioxide.

Good ol' fashion gelatin is fine when it comes to capsules. Now when it comes to gummies or liquid, they are going to use stuff to flavor it because no one wants a tasteless or boring gummy.

My message to you is to decide what you care about. These ingredients are not in massive quantities, but if you pride yourself on not eating anything sythetic, then you are best to stick to a capsule made from minimal ingredients.

3. Third Party Testing

Don't overlook third-party testing. This process ensures the product's quality, purity and most importantly, that what the brand says is in the product is actually in it.

The problem is that many brands simply state that they are '3rd party tested,' without explicitly naming who tests them or where you can find the results. This is bogus.

Look for specific 3rd party testing programs like Informed Choice, NSF Certified for Sport, IGEN (for non gmo). Other programs like regular NSF or GMP are really basic in my opinion and are simply boxes to tick from a manufacturing perspective.

4. Where It's Made

Always check where your supplements are made. Opt for those manufactured in countries with strict regulations, like the USA, Canada or the EU. I am going to assume you live in the USA, so USA made products are generally safe.

5. Dosage Recommendations

Dosage varies, ranging from 100mg to 400mg per day. Most brands on the list set their dose at 200 mg per serving. I typically use 200-400 mg depending on the situation.

If you are just getting started, start on the lower end of that and work your way up after a few weeks as needed. You will find that some brands version of 200 mg is not the same as another brand.

That is why you need to test a few different brands to see which one works and which does not. Lucky for you, I have done most of this work for you in the buyers guide.

Health Benefits of L-Theanine

The health benefits or L-Theanine include stress reduction, enhanced focus, mood benefits, better sleep, anti-inflammatory benefits and potential fat-burning properties. Let's dig into each of these specifically because I find them fascinating.

1. Stress Reduction

Clinical studies show that L-theanine can reduce stress and anxiety by changing certain neurotransmitters in the brain. One study found that with a daily dose of 200-400 mg, L-theanine was effective in reducing acute stress and anxiety symptoms (1).

In another study, L-theanine was thought to lower blood pressure, which shows its potential in reducing physical stress on the heart and blood vessels (2).

2. Focus and Brain Function

L-theanine is scientifically proven to enhance brain function, improving attention span and the processing of information. A study specifically found that 97 mg of L-theanine with 40 mg of caffeine reduced tiredness, significantly improved focus and alertness during mentally demanding tasks (3).

The authors mentioned that L theanine helps to lessen caffeine's negative impact on sleep. From a practical standpoint, you can use caffeine later in the day if you combine it with L theanine. That is how I stay productive in the afternoon (with young kids at home) while still being able to sleep.

Other studies from show how it helps keep you alert while increasing attention span and working memory (4).

3. Mood Boosting Benefits

L-Theanine is also known for its mood-boosting benefits. A study on people suffering from depression showed a reduction in depression and anxiety symptoms when 250 mg of L-theanine was taken daily with their prescribed medication (5).

The researchers think that it works because of how it boosts "feel-good" neurotransmitters such as serotonin and dopamine, which give you those warm and fuzzy feelings when you are in a good mood.

4. Better Sleep

L-theanine is becoming a popular choice for stress-related sleep disturbances. I tend to ruminate when I try to sleep. I'll be calm and zen all-day long, but once my head hits the pillow, my mind races in one thousand different directions.

One thing that helps me quiet my mind is 200-400 mg about 2 hours before bed. It helps me unwind.

Lucky for me, there is some research to back this up. The study shows that 450-900 mg of L-theanine daily for two months can significantly improve sleep satisfaction. Admittedly, that is a pretty high dose (6).

Another study in mice found that the combination of Magnesium-L-Theanine improved sleep by allowing your brain to slip into deep, restorative slow wave states (7).

5. Anti-Inflammatory

Several animal studies have shown that L-theanine can reduce inflammation by inhibiting inflammatory pathways within the body (8). What it find interesting is how it can help with inflammation associated with asthma.

6. Fat Burning

While L-theanine may not directly lead to fat burning, it might might help you lose weight indirectly. Animal studies show that L-theanine could enhance fat metabolism and potentially help with fat loss through its effect on sleep quality and appetite regulation (9).

I know what you're thinking... but we should wait for more research on humans before we tout it as a weight loss miracle.

Possible Side Effects of Consuming L-Theanine

Side effects of L theanine include headaches, dizziness, irritability and gastrointestinal discomfort. You can avoid these issues by starting with a low dose (100 mg for example) to see how your body reacts.

Ask yourself: how do I feel after a few days on this dose? If you feel good then you can gradually increase your dose while checking for side effects.

Also, it may also interact with blood pressure and certain other medications. So, if any of these ring a bell, better get some guidance from your healthcare provider.

Can L-Theanine supplements help with ADHD symptoms?

L-Theanine is shown to reduce ADHD symptoms like hyperactivity, impulsivity and inattention. If you have ADHD, it might help cognitive function, improve attention, and reduce the tendency for hyperactivity, leading to an overall better quality of life (10).

What is the recommended dosage for L-Theanine supplements?

The recommended dosage varies based on individual needs. Generally, it ranges from 100mg to 400mg per day. Make sure that you begin with a lower dose and gradually increase it over time. If you have any questions, ask your doctor.

Does L-Theanine interact with any medications?

L-Theanine can interact with medications for high blood pressure and certain antidepressants. If you're taking medication, makes sure that you check with your healthcare provider before including L-Theanine supplements in your diet.

Is L-Theanine safe during pregnancy?

While L-Theanine is generally safe, there's insufficient evidence regarding its safety during pregnancy or breastfeeding. Since it can lower blood pressure, which can be risky during pregnancy, it's advised to consult with a healthcare provider before using any supplement during pregnancy or lactation.

Can I take L-Theanine daily?

Research has shown that L-Theanine is safe to take daily for up to 8 weeks at a time. However, it's always a good idea to get your healthcare provider's approval before starting a new supplement routine.

Does brand of L-theanine matter?

There are massive differences between different brands of L theanine. Make sure you choose a brand that is 3rd party tested, made in the USA and discloses the type of L theanine they use. Brands that I like are Sports Research and Thorne.

Is it OK to take L-theanine every night?

  • Absolutely. In fact, taking L-Theanine every night has shown to encourage better sleep. Due to its calming effects, it may aid in stress-related sleep disturbances. Unlike some sleep aids, it doesn't come with drowsy side effects, making it ideal to use before bedtime for a restful night's sleep.

I've got good news! L-Theanine can indeed be taken every night. It provides relaxation without drowsiness. Just remember, moderation is key. Don't overdo it, my friend!

Closing Thoughts

L theanine is generally safe to take and shows promising research for it's stress reducing, sleep enhancing and mood boosting benefits. It also helps reduce inflammation and might help with weight loss.

I personally take 200-400 mg of it about 2 hours before I go to sleep. It helps me unwind after a stressful day and really helps me get to sleep. If you are looking to get started, I recommend you try Sports Research or Thorne.

If you have any questions about it or a specific brand or product, leave a comment and I will get back to you asap.

Bluebird Provisions is reader-supported. When you buy through links on our site, we may earn an affiliate commission. As an Amazon Associate, we earn from qualifying purchases.

Disclaimer: this information is for educational purposes only and has not been evaluated by the FDA or CFIA. It is not medical advise. It is not intended to diagnose, treat, cure, or prevent any disease or healthcare issue. Please consult your primary care physician for advise on any of this.

Sources

  1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC/
  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC/
  3. https://pubmed.ncbi.nlm.nih.gov//
  4. https://pubmed.ncbi.nlm.nih.gov//
  5. https://pubmed.ncbi.nlm.nih.gov//
  6. https://pubmed.ncbi.nlm.nih.gov//
  7. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC/
  8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC/
  9. https://pubmed.ncbi.nlm.nih.gov//
  10. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC/

L-Theanine: Everything You Need To Know

L-theanine is an amino acid found in tea leaves and the Bay bolete mushroom. Since the amount you might get in a cup of tea depends on variables like the type of tea plant and how long you brew the leaves, some people use L-theanine supplements to help them relax, destress, and sleep better.

L-theanine also shows promise for cognitive and mental health issues, potentially boosting attention and working memory, relieving depression, and improving symptoms caused by attention-deficit/hyperactivity disorder (ADHD). However, more research is needed to confirm these benefits.

In the United States, the Food and Drug Administration (FDA) does not regulate supplements the way it regulates prescription drugs. That means some supplement products may not contain what the label says. When choosing a supplement, look for third-party tested products and consult a healthcare provider, registered dietitian nutritionist (RD or RDN), or pharmacist.

Supplement Facts

  • Active ingredient(s): 5-N-ethyl-L-glutamine
  • Alternate name(s): 5-N-ethyl-L-glutamine, γ-glutamylethylamide, Suntheanine, theanine

  • Legal status: Over-the-counter supplement. Generally recognized as safe (GRAS).

  • Suggested dose: Varies by condition.
  • Safety considerations: Pregnancy, breastfeeding, chemotherapy;

    potential interactions with medications and other supplements, such as those for blood pressure.

What Are L-Theanine's Benefits?

Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian nutritionist (RD or RDN), pharmacist, or healthcare provider. No supplement is intended to treat, cure, or prevent disease.

Researchers have studied L-theanine's effects for several conditions.

However, it's important to note that better-designed clinical trials are still needed.

Tea leaves.

Getty Images / Dallas and John Heaton

ADHD Symptoms

Researchers have investigated L-theanine for attention deficit hyperactivity disorder (ADHD) symptoms.

Attention issues can have the following causes and/or associations:

Addressing any underlying issues is worth considering. If you have questions about your child's symptoms, it's best to contact their pediatrician.

A study was conducted in male children (8 to 15 years) with ADHD. L-theanine improved total cognition compared to a placebo (an inactive substance). Both L-theanine alone and an L-theanine-caffeine combination also reduced mind wandering.

Caffeine Use in Children

The American Academy of Child and Adolescent Psychiatry (AACAP) advises against caffeine for children under 12 years.

Some children with ADHD may also have significant issues with sleep. Sleep disturbances can impact both a child's and family's well-being.

A clinical study suggested L-theanine helped sleep quality in male children 8 to 12 years with ADHD.

Further, higher-quality studies are needed to confirm these results.

The company is the world’s best Happy Teanine supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.

Correct Diagnosis of ADHD

Correctly diagnosing ADHD is essential. Some gifted (highly or profoundly intelligent) children may have behaviors that seem like ADHD due to boredom or other issues.

ADHD, autism spectrum disorder (ASD), and giftedness can also share overlapping characteristics and can be correlated. A healthcare provider well-versed in both giftedness and neurodiversity can help. Organizations like the National Association for Gifted Children have additional resources.

Another study showed younger males in kindergarten were, as a group, over-diagnosed with ADHD. Developmentally normal behavior has been mistaken for a medical issue. It may be that a lower student-to-teacher ratio (smaller class size) with experienced teachers may benefit children in this case as well.

Ask your child's healthcare provider about questions or concerns. They may refer you to a healthcare provider that specializes in these areas.

Anxiety

Anxiety affects around 12.5% of adults and 9.4% of children in the United States. Unresolved anxiety can cause further health issues.

Scientists found L-theanine has anxiolytic (anti-anxiety) effects. A systematic review (a collection of research on a single topic) suggested L-theanine reduced anxiety in people under stress.

Researchers conducted a study in children between 4 and 17 years with Tourette's syndrome (a nervous system condition causing sudden twitches, movements, and sounds). L-theanine with vitamin B6 reduced tics with anxiety. It's challenging to fully understand L-theanine's effects in this study alone as it was used in combination.

While there's promising evidence, conflicting evidence of theanine's effectiveness for anxiety also exists.

Speak with your healthcare provider if you're experiencing anxiety.

Cognition

Scientists have suggested caffeine may bolster L-theanine's impact on cognition (processing and understanding information) and working memory.

In a study of young adults, L-theanine with caffeine helped with attention.

However, in other studies of healthy adults, L-theanine alone (no caffeine added) had the following effects:

  • Decreased errors

  • Increased attention

  • Enhanced working memory

  • Promoted verbal fluency (retrieving information from memory)

  • Improved executive function

  • Increased selective attention (the ability to select and process information while tuning out distractions)


Cancer

Theanine has been investigated for its anticancer effects in in vitro (in cells in a laboratory) and in vivo (animal) studies.

However, clinical trials (research in humans) are needed before recommendations can be made.

Depression

In one study, researchers added L-theanine to current medication in people with major depressive disorder. The following symptoms improved:

  • Depressive symptoms
  • Anxiety
  • Sleep disturbance
  • Cognitive impairments

Further, high-quality studies are needed.

Please reach out to your healthcare provider if you're experiencing depression. Promptly diagnosing and treating this and other mental health issues is important.

Immune Effects

L-theanine impacts the immune system. In a study of professional athletes, L-theanine affected different immune system markers. It was associated with decreased interleukin-10 (IL-10).

Further study is needed.

Schizophrenia

In people with schizophrenia or schizoaffective disorder, L-theanine was added to regular treatment with beneficial effects.

L-theanine supplementation was associated with the following improvements:

  • Sleep quality
  • Positive and Negative Syndrome Scale (PANSS) scores (assesses how well treatment is working)

Consult with your healthcare provider before adding supplements to your medication regimen.

Sleep

Chronic sleep disorders can seriously affect your quality of life. Sleep disorders are linked with or can worsen the following conditions:

In healthy adults, L-theanine reduced sleep latency (the time it takes to fall asleep), sleep disturbance, and the use of sleep medication.

Some children with ADHD have associated sleep problems, affecting both the child's and family's well-being. In a clinical study of male children 8 to 12 years with ADHD, L-theanine improved sleep.

If you or your child has sleep issues, please reach out to your healthcare provider.

It's essential to evaluate and rule out contributing issues such as:

  • Anxiety
  • Sleep apnea
  • Restless legs syndrome
  • Insomnia
  • Iron deficiency anemia

Sleep issues can be connected with behavior and mood issues in adults and children.

Your healthcare provider can help you figure out and address the root cause.

Stress

Researchers studied theanine for its stress-reducing effects. In young adults, L-theanine reduced stress. It also lowered blood pressure in high-stress situations.

Further study is needed to confirm these results.

What Are L-Theanine's Downsides?

L-theanine has been mostly well-tolerated in clinical trials. However, adverse effects or interactions are still possible, including the following:

  • Allergy: People allergic or hypersensitive to tea or any part of L-theanine products should avoid tea or L-theanine. Carefully read your product labels. If you're having a severe allergic reaction to L-theanine, symptoms may include breathing difficulties, itchiness, and rash. Call 911 and seek prompt medical attention if you have a severe allergic reaction or life-threatening symptoms.
  • Anxiety medications: Theanine reduced anxiety in a clinical study. Theoretically, it may interact with medications or other supplements used for anxiety.


  • Blood pressure medication: Theanine has lowered blood pressure in clinic study.

    Theoretically, it may interact with medications or other supplements that affect blood pressure.
  • Cancer medication: Using L-theanine supplements while undergoing chemotherapy is best done in collaboration with your healthcare provider.

  • Pregnancy or breastfeeding: Pregnant or breastfeeding people should likely avoid L-theanine supplements.

    Speak with your healthcare provider or pharmacist for further information.

How Does L-Theanine Work?

Researchers believe L-theanine improves sleep quality via anxiolysis (reducing anxiety), not sedation.

Scientists believe these effects may be due to theanine's ability to benefit levels of the following:

L-theanine also impacted levels of the following when used with antipsychotic medication:

Researchers think BDNF may help the brain heal itself, which may explain some of theanine's positive benefits.

Dosage

Always speak with a healthcare provider before taking a supplement to ensure that the supplement and dosage are appropriate for your individual needs.

L-theanine is available in the following forms:

  • Capsule
  • Gummy
  • Liquid
  • Powder
  • Soft gel
  • Tablet

Theanine is also found in tea. It's often combined with other ingredients. Vegetarian and vegan products are available.

The following are dosages used in clinical studies. They are not meant to substitute for a consultation with your or your child's healthcare provider:

  • ADHD: In male children (8 to 12 years), 2.5 milligrams per kilogram (mg/kg) of body weight of L-theanine for six weeks was studied.

  • Anxiety: In adults, 200 to 400 milligrams (mg) of L-theanine daily for up to eight weeks were studied.

  • Cognition: In adults, 100 to 400 mg L-theanine for auditory processing was tested, with 400 mg producing the highest results.

    In young adults, 97 mg of L-theanine with 40 mg of caffeine helped attention.

    (The AACAP advises against caffeine for children under 12 years.)

  • Depression: A dose of 250 mg of L-theanine taken daily along with a prescribed antidepressant for eight weeks was tested.

  • Schizophrenia: From 250 to 400 mg of L-theanine taken daily with regularly prescribed medication for up to eight weeks was studied.

  • Sleep: In adults, 200 mg per day of L-theanine for four weeks was studied.

    In children with ADHD-related sleep disturbances, 400 mg daily for six weeks split into two daily doses were tested.

  • Stress: Theanine at doses as low as 50 mg increased relaxation.

    For adults, 200 to 400 mg daily L-theanine for up to eight weeks.

    For young adults, 200 mg of L-theanine were tested.

Similar Supplements

Supplements with anxiety-lowering and/or sleep-inducing effects include but aren't limited to the following:

Physical activity, including but not limited to aerobic exercise and yoga, lowers stress levels and can improve sleep.

Acupuncture has also been touted for its anxiety-lowering and sleep-inducing effects.

Summary

Since its discovery in the s, researchers have investigated L-theanine for ADHD, anxiety, cognition, stress, and more.

While results are promising, more research is needed.

Consider avoiding L-theanine in the following situations:

  • Pregnancy
  • Breastfeeding
  • Chemotherapy

And please do your best to speak with your healthcare provider, registered dietitian nutritionist (RD or RDN), and/or pharmacist about your supplements, prescriptions, and over-the-counter medication.

This way, you can collaboratively come up with a plan that optimizes safety and helps successfully meet your health goals.

Frequently Asked Questions

  • What is L-theanine?

    L-theanine is an amino acid found in tea and some mushroom species.

  • What does L-theanine do?

    Clinical studies suggest L-theanine has antianxiety effects and promotes relaxation, sleep, and cognitive function.

  • How much L-theanine is in green tea?

    One study suggested the L-theanine content of green tea was 6.56 milligrams per gram (mg/g) of tea leaves. Conversely, white tea had 6.26 mg/g, oolong 6.09 mg/g, and black 5.13 mg/g. Anywhere from 1 to 3 g of tea have been used per cup. This means a cup of green tea may have anywhere from around 6.5 to 19.5 mg of L-theanine.

    For more information, please visit Phosphatidylserine Anxiety.