Table of Contents
L-Theanine (r-glutamylethylamide) is a non-dietary amino acid found in green tea (camellia sinensis), and the mushroom Xerocomus badius. Structurally, L-Theanine is similar to the neurotransmitters l-glutamate and l-glutamine.
L-Theanine easily crosses the blood-brain barrier. And taken as a supplement or by drinking green tea, reaches your brain within 30-45 minutes.
L-Theanine can lower blood pressure, rejuvenate and relax you, boost your ability to think, improve focus and change your mood. L-Theanine balances brain chemistry and improves cognitive health.
L-Theanine helps:
- Brain Waves. L-Theanine boosts alpha brain waves (8-12Hz) promoting alert relaxation.[i] And theta brain waves associated with creativity and relief from trauma.
- Neurotransmitters. L-Theanine increases GABA, serotonin and dopamine levels in your brain. Producing an energizing and calming effect. And improving cognition and memory.
- Neuroprotection. L-Theanine is an agonist of NMDA receptors and can inhibit synaptic release of glutamate. Protecting your brain from over-stimulation caused by glutamate, and possible glutamate toxicity.
Overview
L-Theanine (r-glutamylethylamide) is a non-dietary amino acid found in tea. And especially high levels in green tea (camellia sinensis). L-Theanine was first isolated from green tea in Japan by Sakato in 1949.
As an analogue of glutamate and glutamine, it’s hydrolyzed in your intestine and liver into l-glutamate and ethylamine. And easily crosses your blood-brain barrier.
L-Theanine is one of the very few nootropics known to modulate brain waves. It affects alpha brain waves which are associated with relaxation. Providing an alert calmness, L-Theanine helps in promoting super-learning, flow states and joy.
L-Theanine boosts the neurotransmitters serotonin, dopamine and GABA in your brain. As well as increasing Brain-Derived Neurotrophic Factor (BDNF) and Nerve Growth Factor (NGF).[ii]
L-Theanine is known for helping to relieve stress, improve cognition, boost mood and cognitive function.
How does L-Theanine work in the Brain?
L-Theanine boosts brain health and function in several ways. But two in particular stand out.
- L-Theanine reduces physical and mental stress. L- Theanine helps increase alpha brain waves which are associated with mental relaxation and concentration.
One study in South Korea worked with 20 healthy male volunteers aged 18 – 30 years. One group was given L-Theanine tablets, and the other group a placebo daily for 7 days.
Brain waves were measured 40 minutes after administration of the tablets. The researchers analyzed alpha wave power values. And concluded that L-Theanine tablets promoted the release of alpha brain waves related to mental relaxation and concentration.[iii]
In May 2016, researchers at Simon Fraser University in Canada developed a technology to clinically measure brain wave patterns. With this technology, we’re now able to detect cognitive dysfunction before it happens. Imagine the implications of this new technology when applied to the nootropics world.[iv]
- L-Theanine increases neurotransmitters. Research shows that L-Theanine increases dopamine, serotonin, and GABA in your brain.[v] And it reduces the excitatory neurotransmitter glutamate which is associated with stress, tension and agitation.[vi]
A study done in Japan worked with 12 people who underwent 4 separate trials. One in which they took L-Theanine at the start of the experiment. One in which they took it half-way through. And two control trials in which they took either a placebo or nothing.
The results showed that L-Theanine resulted in a reduction in heart rate and s-IgA associated with acute stress. The researchers concluded that L-Theanine could cause anti-stress effects via the inhibition of cortical neuron excitation.[vii]
How things go bad:
As we get older, our brain chemistry and energy metabolism changes.
↓ Neurotransmitter levels decline
↑ Glutamate levels increase
↑ Stress levels increase
↓ Long-term memory and mood decline
↓ Quality of sleep declines
All of these changes can happen at any age once we reach adulthood. And are contributing factors to the neurodegenerative diseases of aging, and quality of life.
L-Theanine benefits
L-Theanine energizes without draining, calms without putting you to sleep, and motivates without causing a jagged edge.
Tea (as a source of L-Theanine) can have as much caffeine as some coffees. And yet doesn’t exert the same “speedy” effect. And the reason is the ingredient L-Theanine.
You can actually see L-Theanine’s effect in your brain using an EEG. Brain waves are smoothed out rather than flattened out.[viii] So your body is relaxed, your mind is calmed, but you don’t get sleepy. And L-Theanine, once it crosses the blood-brain barrier, raises levels of serotonin and dopamine.[ix]
L-Theanine even improves your quality of sleep. Researchers in Japan gave volunteers 200 mg of L-Theanine daily and recorded their sleep patterns. Sleep quality, recovery from exhaustion, and feeling refreshed were all enhanced by L-Theanine.[x]
And L-Theanine puts you in a better mood. Once it crosses your blood-brain barrier, L-Theanine changes levels of amino acids affecting serotonin, dopamine, and GABA. Having a modulating effect on mood.[xi]
How does L-Theanine feel?
Your unique neurochemistry including neurotransmitters, brain waves, brain structure and even regional brain activity will influence your response to L-Theanine.
Most neurohackers report a calming effect within 30 – 45 minutes of taking L-Theanine. Cognition gets a boost, and energy levels rise without the jitteriness caused by stimulants like caffeine.
Some report L-Theanine has stopped their anxiety and panic attacks. Just don’t combine it with anti-anxiety meds like Xanax.
Most report an overall improvement in the sense of well-being and quality of life. And nearly all remark on better quality sleep.
L-Theanine Clinical Research
Green Tea reduces incidence of stroke
Research has found that if L-Theanine is present in the body at the time stroke occurs, brain damage will be significantly reduced.
In this monster study done in China, researchers selected 14,212 subjects from 12 provinces. Ages ranged from 35 – 60 years old. The study looked at tea drinking status, dose and type of teas.
This study concluded there was a 40% decreased risk of stroke in those who drank green, black or jasmine teas.[xii]
L-Theanine improves memory
In this double-blind, placebo-controlled study, the effect of L-Theanine on memory and attention was investigated.
91 subjects with mild cognitive impairment were enrolled in this study. One group received 1,680 mg of L-Theanine daily for 16 weeks. And the control group received a placebo.
The study concluded that L-Theanine increased brain Theta waves associated with cognitive alertness and creativity. And there were improvements in memory. The results of this study suggested that L-Theanine has potential as an intervention for cognitive improvement.[xiii]
And that is an understatement by any stretch. People spend years meditating. With the goal of reaching consistent access to brain wave states like Theta. In this trial, they did it with a dose of L-Theanine. The same type of dose you could get with a few cups of quality green tea.
L-Theanine reduces stress
Considerable research has been dedicated to L-Theanine and its benefits to stress reduction in both animal and human studies. And we have ample documentation that corticosterone and stress exert negative effects on memory.[xiv]
Corticosteroids which are secreted after stress, have a profound impact on long-term potentiation and memory formation.[xv]
In this animal study, rats were fed water containing L-Theanine for 3 weeks and put through some stress inducing exercise. The researchers found that corticosterone levels were lower in the rats who used L-Theanine compared to those who had none.
In fact, stress had no effect on the animals who were fed L-Theanine. Memory was not affected. The researchers concluded that L-Theanine modified corticosterone secretion. And L-Theanine is a strong preventive measure in preventing memory loss otherwise induced by stress.[xvi]
L-Theanine Recommended Dosage
Recommended dosage of L-Theanine is 100 – 400 mg once or twice per day. With a maximum of 1,200 mg per day according to the Cleveland Clinic.[xvii]
L-Theanine is water soluble so you can take it with water.
Labels on quality green tea often only display the amount of green tea leaf available in each bag in milligrams (mg). But not its L-Theanine content. Green tea that’s steeped correctly will offer 1-2% L-Theanine per cup. So 1,500 mg of green tea leaf would be about 30 mg. of L-Theanine (at 2%).
We often say that YMMV, and this is especially applicable to L-Theanine. Find out what works best for you. Start at a lower dose like 100 mg. And work your way up until you achieve the effects you’re looking for.
L-Theanine Side Effects
L-Theanine is a naturally occurring amino acid found in plants like tea or one species of mushroom. So it’s considered non-toxic and very safe.
Theanine seems to decrease blood pressure. So if you’re on meds for high blood pressure, use L-Theanine with caution. Your blood pressure could go too low.
Type of L-Theanine to Buy
L-Theanine is available in green, black and white teas. Green tea contains the most L-Theanine.
A great side benefit for neurohackers is green tea also contains caffeine. A cup of good quality green tea has less caffeine than a cup of coffee. About 10 mg less.
L-Theanine + Caffeine stack
One study done at Unilever in the UK looked at the combined effects of L-Theanine and caffeine on cognitive performance and mood. They compared 50 mg of caffeine with and without 100 mg of L-Theanine.
The research team had 27 volunteers participate. And based measurements on word recognition, rapid visual information processing, critical flicker fusion threshold, attentions switching and mood.
Performance was measured at the beginning, and again 60 minutes and 90 minutes after consumption. Separated by a 7-day washout period.
Caffeine improved alertness at 60 mins. And accuracy on attention-switching at 90 mins. The L-Theanine and caffeine combination improved both speed and accuracy, and reduced susceptibility to distracting information on the memory task.
The research team concluded that, “L-Theanine and caffeine in combination are beneficial for improving performance on cognitively demanding tasks”.[xviii]
And for an added bonus, L-Theanine takes the jittery-edge off of caffeine consumption.
The best pre-formulated caffeine + L-Theanine stack I’ve tried, and use is the new Performance Lab® Caffeine 2. It contains Natural Caffeine (from Coffea Robusta seeds) 50 mg, L-Theanine 100 mg, L-Tyrosine 250 mg, with a balanced NutriGenesis® B-Complex. For alert clean energy without the jitters.
L-Theanine from green tea
Extracting the optimal amount of L-Theanine from green tea is both art and science.
Researchers at the University of Newcastle in Australia set out to determine optimal conditions for water extraction of L-Theanine from green tea. They examined 4 different extraction methods. And learned that temperature, extraction time, ratio of water-to-tea and tea particle size had significant impacts on extraction yield of L-Theanine from green tea.
They concluded, “The optimal conditions for extracting theanine from green tea using water were found to be extraction at 80 °C for 30 min with a water-to-tea ratio of 20:1 mL/g and a tea particle size of 0.5-1 mm.” [xix]
So to get the most nootropic value when using green tea as your L-Theanine source – follow the directions. Just sayin’…
L-Theanine Supplements
L-Theanine is available in capsule or tablet form from several supplement manufacturers. Japanese company Taiyo is the oldest and most established company in the green tea supplement industry. Taiyo developed and patented a method for L-Theanine extraction from green tea called ‘Suntheanine®’.
Suntheanine can be found in some of higher quality pre-formulated nootropic stacks. For example, Mind Lab Pro® contains 11 brain enhancing nootropic compounds including Suntheanine.
Research has shown that some supplement makers using their own extraction method for L-Theanine, contain more than just the “L” form of Theanine. Turns out if it’s not done exactly right, you end up with a “D” form of Theanine.
D-Theanine may have a very different action in your body than L-Theanine. We’re not saying it’s dangerous. You just may not get all the benefit of pure L-Theanine.
So read the labels and reviews by people who have tried the product.
I recommend Mind Lab Pro because it uses Suntheanine. And addresses all aspects of anxiety resistance, memory and cognitive enhancement, stabilizes mood, brain repair, and maintenance.
This premium nootropic stack is designed to affect neurotransmitters, cognitive energy, brain waves, neuroprotection, and regeneration. See my Mind Lab Pro review for a detailed report.
You will also find Suntheanine® in the new Performance Lab® Caffeine 2. It contains Natural Caffeine (from Coffea Robusta seeds) 50 mg, L-Theanine 100 mg, L-Tyrosine 250 mg, with a balanced NutriGenesis® B-Complex.
Nootropics Expert Recommendation
L-Theanine 100 – 500 mg per day
I recommend using L-Theanine as a nootropic supplement.
Your body cannot make L-Theanine on its own. It’s a non-dietary amino acid only available from tea (and one little-known mushroom).
L-Theanine affects Alpha and Theta brain waves. This alone will help calm your mind, reduce stress, and help you stay alert. You’ll get even more cognitive benefit by stacking L-Theanine with caffeine.
L-Theanine helps boosts the neurotransmitters dopamine, serotonin, and GABA. Improving alertness and attention. And boosting cognition and memory.
And it reduces the excitatory neurotransmitter glutamate which is associated with stress, tension and agitation.
L-Theanine helps to prevent strokes, and even reduces the damaging effects if you’ve had a stroke.
And L-Theanine has been shown to improve sleep quality.
I suggest starting with a dose of 100 – 250 mg of L-Theanine daily for nootropic use. Using either a quality supplement, or high quality green tea.
Mind Lab Pro contains a synergistic blend of 11 brain enhancing nootropics covering all aspects of cognition and brain health. See my full Mind Lab Pro review for more.
Or for a smooth energy boost I recommend the new Performance Lab® Caffeine 2. For alert clean energy without the jitters.
Join The Discussion - 315 comments
Tony
September 11, 2021
Hi David,
Good article. I love L-Theanine and I’ve been experimenting with it and other nootropics and how that changes some of my bio-markers.
I think I’m going to take L-Theanine my whole life.
One of the things worth mentioning is that L-Theanine combined with Ashwagandha and Lions Mane was able to drop my sleeping heart rate below 50 bpm and increase deep sleep above 40% of my total sleep hours.
On a personal note, nothing wrong with patented nootropics formulations like Mind Lab Pro, but I find them overpriced. Not too mentioned that we’re not all the same and dosage might differ.
Therefor buying nootropics separately and combining them, in my case generates better results.
Best,
Tony
David Tomen
September 11, 2021
Tony, you point out a couple of important things. There is no “one pill” solution for anything in this life. And esp. for someone just starting out it’s better to assemble a stack unique to you that works best. Then if you are lucky enough to find a pre-made stack to can save you some money and meet your goals that’s even better.
I disagree with you on one point and that is how some pre-made stacks are over-priced. I know for a fact that if you tried to put together a stack that mimics Mind Lab Pro including the patented and high quality ingredients they use it would cost much more than their asking price. It’s only “over-priced” if it doesn’t meet your needs.
Noted your experience with sleeping heart rate and deep sleep with those 3 supplements. It’s amazing how powerful the right combination can be.
Tatiana
September 11, 2021
Hi, do I have to take L-theanine without food? Thank you!
David Tomen
September 11, 2021
Tatiana, L-Theanine is water soluble which means it will get absorbed just taking it with a glass of water.
Mick
September 11, 2021
Hi David,
L-Theanine is my favourite nootropic. I bought it from different sites before, but I never knew that there’re natural L-Theanine and synthetic one. The site I want to purchase it from is in China, and they’re confusing me by sending messages about – natural 20% L-Theanine and synthetic 98%. Natural type that they sell cost more than twice the price of synthetic. As far as I know natural is usually batter than synthetic.
David are you familiar with these two kinds of L-Theanine? And if you are, can you please give me a few tips about it, like – is it worth trying synthetic? Is L-Theanine from familiar sites like – Nootropics Depot and LiftMode sell natural form of L–Theanine or synthetic?
Any advice would be greatly appreciated!
David Tomen
September 11, 2021
Mick, the Japanese company Taiyo is the oldest and most established company in the green tea supplement industry and they have developed and patented a method for L-Theanine extraction from green tea called ‘Suntheanine®’. Those are your two main options for L-Theanine – either the natural Suntheanine® or a synthetic form of this supplement. Studies back up the efficacy of Suntheanine® but I’ve not seen a direct, side-by-side comparison of the two. Logic tells us the our bodies prefer natural over synthetic because it doesn’t need to convert anything.
Mick
September 13, 2021
Thanks David!
Marigold
August 26, 2021
I took L-Theanine the other night an hour before bed, and soon after I began to get heart palpitations. Was such an incredible pounding. The pounding eased after about 30 minutes. I did feel sleepy (but I was worn out). I prob slept at 10:30 then woke up and it was only 1230. Felt jittery. This is like the complete opposite of what L-Theanine does. Looking it up I only found a few hits on forums where others mentioned the same thing. As you type into a search bar L-Theanine heart, palpitations does come up, so it must be a search. But why would this happen. I was told to take it before bed to lower night time cortisol.
David Tomen
August 26, 2021
Marigold, L-Theanine does lower cortisol and boosts Alpha and Theta brain waves. But it also promotes dopamine along with GABA and serotonin. So you either got an adulterated supplement or you had a reaction to the dopamine boost.
Davin
October 15, 2021
Hey David thanks for all the information. I read not to take with anxiety meds Ida that manning SSRIs? I’m trying to help out someone but they take anxiety meds and so far I can’t find anything that might help that won’t interact.
David Tomen
October 16, 2021
Davin, SSRIs and anti-anxiety meds are two very different drugs. Wikipedia is a good source for looking up the Pharmacology or mechanism of action for drugs. Just type in the drug name (there are listed under the chemical name and not the brand name) and you’ll see how each one works in the brain.
Anti-anxiety meds are typically benzos and act on a sub-receptor of the GABAa receptors. SSRIs act on serotonin receptors.
So, anything that affects GABA are often contraindicated with anti-anxiety meds. And anything that affects serotonin receptors (and sometimes norepinephrine receptors) may interact with nootropics to boost serotonin.
Lisa
April 5, 2022
I took 500mg before bed but it left me completely awake and unable to sleep for hours. Was it just too high dose or do I just have atypical response? I have been desperate for help with my middle night wakings. Thx for any help.
David Tomen
April 5, 2022
Lisa, try cutting the dose back to 200 – 300 mg of L-Theanine and see if that helps. If not you could be having an “atypical response” because your system is taking advantage of the dopamine more than the GABA and serotonin.
But if all you are using is L-Theanine for better sleep you’ll be disappointed. See this article for sleep and how it works: https://nootropicsexpert.com/best-nootropics-for-sleep/
Andrew
July 29, 2021
i’m updating my stack, would like to run something by you
If I buy the powered l-theanine, how much in a teaspoon would equal 50 or 100mg
I want to get the powered as it does not contain those awful toxic other ingredients
I am looking at getting this one: Now Foods, L-Theanine Pure Powders
You say it is good for sleep, Wanna changed from the capsule due to those toxins
I take NAC after the last meal at night
and Glycine and Lemon Balm before bed – sometimes (rarely) melatonin 1MG only
In the day I’m taking
DHA – 1000MG
performance lab – vision
B-complex
Vit D
is this combo fine and safe
David Tomen
July 30, 2021
Andrew, you need to get a scale for accurate measurement and not guess about weight by using a teaspoon. I’ve used this one in the past which is accurate and works well: https://amzn.to/3iaL9Ci
Yes, that combo is safe.
Andrew
August 4, 2021
I ended up getting this: Paradise Herbs – Optimized Sun Theanine
but realized it contains optiMSM ?
what is that is it good?
David Tomen
August 6, 2021
Peter, they claim that OptiMSM increases the absorption of L-Theanine and works in synergy with it. I have not done the research on MSM so can’t tell if that claim is true.
Andrew
August 10, 2021
How much l-theanine do you take before bed? how long should I take it before bed?
Thanks
David Tomen
August 10, 2021
Andrew, 400 mg L-Theanine about 60 minutes before bed.
Andrew
August 12, 2021
May I asked what brand you take?, I got suntheanine but says it does not make one sleepy but relaxed
David Tomen
August 12, 2021
Andrew, I use this one: https://amzn.to/2VUFebY. Take enough of any L-Theanine supplement and it will make you sleepy.
Jennifer Isaac
July 20, 2021
I suffer from Anxiety and Depression. My Depression is probably due to the Anxiety. Which is the best supplement for it? L-Theanine or Lithium Orotate? If L-Theanine would work the best how much and is it okay to take with Carbamazepine?
David Tomen
July 21, 2021
Jennifer, see my reply to your comment under the comments thread where you asked the same question here: https://nootropicsexpert.com/ashwagandha/
Bill
June 5, 2021
Hi David, Why would L-Theanine suddenly cause anxiety after working so well? I upped my dose to 200 mg, and the third dose at that level gave me anxiety. I was at 100 twice a day and had just upped the dose. I also took Metformen and rovisatin within about 15 min of the L-Theanine As I had forgotten to take it after dinner. The night before was one of the best night’s sleep in a long time. Any help would be appreciated. Thanks Bill
David Tomen
June 5, 2021
Bill, more than likely it was a reaction to combining L-Theanine with Metformin. Or it was doubling your dose. You’ll need to test these and see which it is.
Try Metformin with L-Theanine again and see what happens. And if that isn’t the cause then it’s the increased dose that you are having problems with.
Bill
June 5, 2021
Thank you David.
David
July 20, 2021
Currently using natruimvalproaat (depakine)for mood disorder. Can I combine L theanine as my mood is very low and antidepressants don’t seem to help.
David Tomen
July 21, 2021
David, L-Theanine is not contraindicated with this drug as far as I can see.
Lorna
March 12, 2021
Hello David,
Thank you. Your video and article were informative and helpful.
I was reading your What-I-Take for sleep. Would you please share which are best taken before bed, beside glycine? You mentioned: Performance Lab® Sleep, Magnesium, L-Tryptophan, Lemon Balm, L-Glycine, and L-Theanine. Anything else I missed? Thanks again!
David Tomen
March 12, 2021
Lorna, the only thing missing from that list that I use every night is CBD Oil “Calm” gummies made by Charlotte’s Web.