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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 Click for 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, Click for 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 Click for 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 Click for Performance Lab® Caffeine 2 . For alert clean energy without the jitters.
Join The Discussion - 330 comments
Tom Himanen
July 31, 2019
I have taken a habit to eat coffee instead of brewing it. It has been very practical. In fact, I have started taking a spoonful of instant coffee and flushing it down with water.
It has been extremely practical since it reduces the amount of (apparently) unnecessary steps and saves time. Especially on the road it is sometimes necessary to do it that way in order to get coffee.
However, because of L-theanine I have begun to consider switching coffee to tea. Tea also probably has lower risk for causing cancer since it is not roasted.
How much of L-theanine and caffeine you think absorbs from teaspoon of green tea, for example?
David Tomen
July 31, 2019
Tom, see this section for L-Theanine content in green tea: https://nootropicsexpert.com/l-theanine/#l-theanine-from-green-tea.
Caffeine will vary depending on the green tea used. You’ll sometimes find caffeine content in mg per cup on the package.
Tom Himanen
August 2, 2019
Thank you David! As far as I can understand, extraction using hot water increases remarkably my chances to absorb L-theanine from the tea. But if I skip extraction step and eat tea leaves, I probably need to consume bigger mass of tea leaves. So I was just wondering, how much more I must consume tea if I eat the leaves instead of drinkin it?
PS. I love your YouTube video that have a very clear structure which makes them the first source of information when I quickly want to get familiar with new nootropics I don’t know yet.
David Tomen
August 2, 2019
Tom, I have no idea. I’ve not seen any studies on L-Theanine from eating tea leaves. Likely because it’s not a very common way of consuming tea.
Tom Himanen
August 3, 2019
Okay, gotta try it myself then. Do you have any idea how to measure this other than observing my gut feeling?
David Tomen
August 4, 2019
Tom, you’re going to need to go with your gut on this. And do some testing to see what works best for you.
Maxim
July 3, 2019
David, will that be ok to open the L-Theanine capsule (or use powder) and mix it right in the cup of hot coffee? Or high temperatures should be avoided? Thanks!
David Tomen
July 4, 2019
Yes, that will work Maxim. Although if the temp. is too high the L-Theanine may lose some of its effectiveness.
Angelina
June 14, 2019
Hey, I have no bi polar mixed effective state and I take a mood stabiliser called lamictal. I also take dexamphetamine sometimes for adhd but when I need to do certain tasks. Just wondering if mixing L-Theanine, L-Carnitine, Creatine, ashwaganda is ok? I used to take lithium orotate but not sure if I should mixed that or not.
David Tomen
June 15, 2019
Angelina, I’m not aware of any contraindications. But here’s your homework; use Wikipedia and learn exactly how each of these prescription drugs work (i.e. pharmacology or mechanism of action). Then come back here and check the mechanism of action for each nootropic supplement you are using.
What you’re looking for is if a drug directly boosts the same neurotransmitter or has the same mechanism of action as the nootropic. If it does then you could get into trouble. If they work differently then chances are you not going to run into trouble.
Another way to check is input each of your drugs into this checker and see if any of the supplements are in the list for the drug: https://www.drugs.com/drug_interactions.html
Spenser Courville-Taylor
May 9, 2019
Hi! Thanks so much for your the info! So i’ve been reading on these different compounds and so far i’m thinking of a stack containing L-Theanine + L-tyrosine + Phenylalanine + 5 HTP+ Vitamin B6. I would also like to drink 3 cups of coffee per day. I am unclear on the dosage when combining all of these as well as know for sure if they all combine well and would love to be educated. Also, would you suggest adding anything else? Thanks so much!!
For reference- I have been taking alpha brain for a few months and am looking for something a little bit more.
David Tomen
May 10, 2019
Spenser, refer to the recommended dosage for each by going to each individual review: https://nootropicsexpert.com/nootropics-list/
Except for 5-HTP because it’s a very potent supplement and should only be used if your dopamine levels get too high. Or you are extremely deficient in serotonin. But even then it’s safer to use L-Tryptophan.
Matt
April 24, 2019
Hi David,
I am sooo frustrated with L-Theanine. Everone and their brother recommends it for my anxiety and insomnia. The two times I have taken it I get an all day dull headache. I have NO issues with Green Tea and it makes me feel amazing but of course doesn’t do much for sleep. Do I need a low dose? If so will I even feel the benefits. -Thanks
David Tomen
April 25, 2019
Matt, if you have a negative reaction to supplementing with L-Theanine it’s likely that this nootropic is not for you. Each of us is ‘wired’ different have a unique biological profile. Clearly, something in L-Theanine is having a negative effect on you. And it could be because it raising serotonin.
Mick
April 17, 2019
Hi David
I’m taking L-Theanine for social anxiety for a little bit less than a year now, and it really helps.
At the moment I have L-Theanine in 100mg, 200mg, 400mg capsules and powder.
For more convenience I ordered 500mg capsules, on EBay from someone called -herbalextractseller somewhere in India. And I’m taking it for about two weeks now.
Before I was taking 900mg a day, divided into two doses, 500mg in the morning (400mg powder/capsule + 100mg M.L.P.) and the second dose of 400mg after five hours from my first dose.
At the moment I’m taking 1000mg a day, divided into two doses, 600mg in the morning (500mg capsule + 100mg from M.L.P.) and the second dose of 400mg after five hours from my first dose.
Since I started 500mg capsules and I went up 100mg, I don’t feel any difference.
This brand is called – Maple life sciences. Do you think it could be because it is bad quality?
I would try another brand, but there’s not much choice on 500mg L-Theanine capsules. This is the only one I found so far.
David what can I do to see if this 500mg capsules work?
May be there’s some kind of a test I can do, like to miss a dose and wait until I will get anxious, and then take it and see if it works?
Any help is greatly appreciated
Thank You David for your help
David Tomen
April 17, 2019
Mick, most L-Theanine supplements come in 100 or 200 mg which seems to be the industry standard. And one thing I’ve found over years of using nootropic supplements is quality matters. It’s why I find 2 or 3 manufacturers that I trust and get all my supplements from them.
If cost is an issue I suggest finding a manufacturer who you know tests their product. And has consistent great reviews. Put together the equivalent dose from someone like Nutricost and try it one day. Then try your product from India the next day. Then compare how you feel.
Do not take chances please on your health. It’s too much of a risk in my opinion on getting a supplement from an unknown company on a place like eBay. Unless that company have been vetted by you and you know they are producing a quality supplement.
Mick
April 17, 2019
OK David, I will try the same dose with manufacturer called NOW, and the next day I will try this product from India again, and see if I can feel the difference.
Thank You David for your help
addie
March 26, 2019
hi
i have been using l theanine to take care of my insomnia,and for better attention and focus at work..i started with 200mg daily and then reduced to 100mg daily before sleeping.i took the supplements for 5months at a stretch.i loved the way it kinda calmed me down
suddenly due to a lil work stress,i got panic attacks which lasted really long,i have never faced any anxiety related or haven’t been depressed about any thing.the panic attacks were severe,just made me think if l theanine is responsible for the sudden panic attacks.thank u
David Tomen
March 26, 2019
Addie, the only way that I can possibly think of where L-Theanine may cause panic attacks is if it caused your blood pressure to go too low.
Steve
August 8, 2019
Hi David,
I read one article L Theanine can potentially reduce serotonin. Is it true that it can?
Thanks
Steve
David Tomen
August 9, 2019
Steve, don’t believe everything you read on the Internet. 🙂 L-Theanine increases serotonin according to these guys: https://www.ncbi.nlm.nih.gov/pubmed/17182482
Steve
August 15, 2019
Hi David,
I can’t thank enough for your confirmation.
Thanks
Steve
Francisco
March 24, 2019
How long does the effects of L-Theanine last?
David Tomen
March 25, 2019
Francisco: L-theanine plasma concentration reaches the peak between 32 and 50 min after oral ingestion, and its half-life ranges from 58 min to 74 min in humans.
It has also been reported that L-theanine could influence the secretion and function of neurotransmitters in the central nervous system even at 30 min after oral administration. – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3518171/