L-Theanine is a “unique non-protein amino acid found in green tea” which according to the study below, has shown benefits when used short-term or acutely as a supplement for it’s anti-stress effects, reducing anxiety, improving sleep quality, improving cognition and even easing depression.
This 2019 study, Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial, aimed to examine the effects of four weeks use of l-theanine:
on stress-related symptoms and cognitive functions in healthy adults. Participants were 30 individuals (nine men and 21 women; aged 20-69) who had no major psychiatric illness.
The trial was randomized, placebo-controlled, crossover, and double-blind.
L-theanine (200 mg/day of Suntheanine), was used by study participants before going to bed each night and was used for four-weeks.
Study participants who used the theanine for two weeks observed the following:
- For sleep: Reductions in sleep latency (the amount of time it takes to fall asleep), sleep disturbance and less use of sleep medication
- For cognitive function: Improvements in verbal fluency (especially letter fluency) and improvements in executive function (planning, multi-tasking etc)
The Japanese versions of The Self-rating Depression Scale, State-Trait Anxiety Inventory-trait, and Pittsburgh Sleep Quality Index (PSQI) scores decreased and the study concludes as follows:
Our findings suggest that L-theanine has the potential to promote mental health in the general population with stress-related ailments and cognitive impairments.
The authors also note that “there were no significant adverse events, demonstrating the safety of four weeks of L-theanine administration.”
As expected, the participants saw increases in serum theanine concentrations.
Some of the reported possible mechanisms of action
Here are some of the reported possible mechanisms of action of theanine from some studies referenced in his paper:
- via glutamate receptors (improving cognitive dysfunction)
- as a neuroprotective agent and “increases in brain serotonin, dopamine, GABA levels” (improving mood and focus and reducing anxiety)
- enhances hippocampal activity (the hippocampus has a major role in learning and memory)
- via a proposed increase in the expression of brain-derived neurotrophic factor (BDNF) in the hippocampus (BDNF is a protein implicated in the stress response, long-term memory, Alzheimer’s disease, and psychiatric disorders)
Impacts on cortisol levels?
What is unusual and inconsistent with previous studies, is the fact that there was “no significant effect on cortisol or immunoglobulin A levels in the saliva or serum.” The authors report that “the reduction of salivary cortisol and immunoglobulin A levels may be a short term, recoverable effect of L-theanine administration.”
Update Sept 2025:
In this 2021 paper, A Randomized, Triple-Blind, Placebo-Controlled, Crossover Study to Investigate the Efficacy of a Single Dose of AlphaWave®l-Theanine on Stress in a Healthy Adult Population “there was a significant reduction in salivary cortisol with a single dose of AlphaWave® l-Theanine relative to the placebo, immediately following the stress-inducing task 1 h post-dose.”
In other words, within an hour of taking AlphaWave l-theanine, cortisol levels were lower. This paper also mentions that in a previous study, cortisol levels were only lower 3 hours after taking theanine.
Suntheanine and AlphaWave are different theanine products, each produced by their own proprietary manufacturing process. There are a number of other l-theanine products/manufacturing processes and this may explain why some individuals do well on some theanine products and not others, and why impacts on cortisol levels may vary.
Theanine or GABA – which one to use when?
I typically start my clients with a trial of GABA Calm for low GABA symptoms like physical tension, stress and overwhelm, panic attacks and insomnia. If we are not getting all the expected benefits with GABA and there is a need for added cognitive benefits then we’ll consider adding theanine too. Some folks find one works better than the other and some like a combination (at the same time or theanine in the day/GABA at night or GABA in the day/theanine at night).
I recently reached out on facebook asking:
“Theanine or GABA? Which do you prefer for anxiety and why? How much helps? And any other benefits (like reduced body pain, better thinking/cognition, easing IBS (irritable bowel syndrome) and gut pain, reduced cravings, less negative self-talk etc)? Or do you like a combination of both?”
As you can see from these varied responses it’s a matter or trialing both to find what works for each person’s unique needs:
- Lorraine shared this: “They are both good, but I reach for GABA Calm first.. 2 or 3 lozenges. If anxiety doesn’t leave quickly with GABA ( which works well for a panic attack), and I continue to have anxiety humming along in the background, then I’ll reach for theanine.”
- Jackie shared this: “I take 200mg theanine in morning, then 100mg GABA around 4pm, when the kids get home from school. I had a panic attack in the middle of the night last week, took GABA 100 mg, then seemed to calm down.” I asked if theanine gives her a feeling of calm focus and she said: “yes, I think so. I noticed if I take 200mg of GABA, it makes me drowsy.”
- Evelyn shared this: “I use both at night for sleep. If I could only use one it would be l-theanine.” Theanine is more consistently helpful for stress reduction and sleep for me. I use 200mg. When I use GABA it’s 500mg of chewables.”
- Sara shared this: “GABA during the day, theanine at night.”
- Karine shared this: “GABA!! The Source Naturals Theanine Serene with Holy Basil is really good. But GABA Calm (also Source Naturals which is a sublingual lozenge) is the only thing for a severe issue/episode and helps me concentrate right before an important presentation at work etc. Pure GABA from any supplier is good for long periods where you need a boost or to tone down general anxiety. I also bought a probiotic that also includes GABA (Jarrodophilus Mood) and notice it improves digestion too.”
Some of my top GABA/theanine products
You can find my favorite GABA/theanine combination product, a theanine-only product and my most popular GABA products on the supplements blog here (and with details for how to set up an account for my online store)
Nutritional Fundamentals for Health GABA-T SAP: 300mg GABA, 150mg theanine. This is pleasant-tasting when opened on to the tongue and works very well when GABA Calm can’t be used.
Pure Encapsulations L-Theanine: 200mg theanine. This is also pleasant-tasting when opened on to the tongue. Unlike like GABA, it can also be swallowed.
Source Naturals GABA Calm. This is a pleasant-tasting sublingual product that is my most popular and most effective form of GABA I use with my clients. It can be used in conjunction with theanine.
Enzymatic Therapy GABA: 250 mg GABA. This is also pleasant-tasting when opened on to the tongue and works very well when GABA Calm can’t be used. It can also be used in conjunction with theanine.
BeSerene IR (instant relief): a topical GABA/theanine cream which can be used in conjunction with other GABA and theanine products or instead of them.
Additional resources when you are new to using GABA or theanine and other amino acids as supplements
We use the symptoms questionnaire to figure out if low serotonin or low GABA or low dopamine or other neurotransmitter imbalances may be an issue for you.
If you suspect low levels of any of the neurotransmitters and do not yet have my book, The Antianxiety Food Solution – How the Foods You Eat Can Help You Calm Your Anxious Mind, Improve Your Mood, and End Cravings. I highly recommend getting it and reading it before jumping in and using amino acids on your own so you are knowledgeable. And be sure to share it with the practitioner/health team you or your loved one is working with.
There is an entire chapter on the amino acids and they are discussed throughout the book in the sections on gut health, gluten, blood sugar control (this is covered in an entire chapter too), sugar cravings, anxiety and mood issues. The importance of quality animal protein and healthy fats is also covered.
The book doesn’t include product names (per the publisher’s request) so this blog, The Antianxiety Food Solution Amino Acid and Pyroluria Supplements, lists the amino acids that I use with my individual clients and those in my group programs.
If, after reading this blog and my book, you don’t feel comfortable figuring things out on your own (i.e. doing the symptoms questionnaire and respective amino acids trials), a good place to get help is the GABA QuickStart Program (if you have low GABA symptoms too). This is a paid online/virtual group program where you get my guidance and community support.
If you need serotonin support, the Serotonin QuickStart Program is a good place to get help. This is also a paid online/virtual group program where you get my guidance on using tryptophan and 5-HTP safely, and community support during 5 LIVE Q&A calls. You can sign up to be notified when the next live launch of this program is happening.
If you are a practitioner, join us in The Balancing Neurotransmitters: the Fundamentals program. This is also a paid online/virtual program with an opportunity to interact with me and other practitioners who are also using the amino acids.
Now I’d love to hear from you
Please let us know … theanine or GABA: which do you prefer for anxiety and why? How much helps? And any other benefits (like reduced body pain, better thinking/cognition, easing IBS gut pain, reduced cravings, less negative self-talk etc)? Or do you like a combination of both?”
Feel free to share and ask your questions below.
I have not tried GABA but have had decent luck with L-theanine for lowering overall anxiety levels. I have panic attacks when I go any distance by car so if I know I’ll be going out somewhere I will take 200mg on an empty stomach. It does not completely stop my anxiety but it makes it much more manageable. Btw, I love your picture of the beach. I live in Washington State but have visited the Palm Beach area and keep considering relocating down there.
Brandi
Thanks for sharing how theanine helps lowering your overall anxiety levels. With fears like car travel we also often look at low serotonin and address this with tryptophan or 5-HTP (especially when there are panic attacks). GABA (always sublingual) can also often help as an added layer for the theanine support.
I looked at GABA Calm, but saw that it had Tyrosine in it. I was concerned that it might keep me up. Is this not an issue?
I have a question for you. I am concerned if I took L-Theanine if it would cause more problems with my esophigitis and with my hiatus hernia.The reason why I am asking you this is because I bought a powder form of L-Lysine which helps with anxiety and depression. I used half a teaspoon ,added it to some boiling water once or twice a day and it flared up my esophigitis issues because L-Lysine is an essential amino acid. I am dealing with severe anxiety, social phobia and depression. I am hoping that the L-Theanine and Gaba would work for me. My doctor put me on Effeor 150mg. I am very sensitive to perscription medicatoins and the effeor causes many side effects especially with the esophigitis and stomach. I look forward to hearing from you.
Sincerely; Sandra Lukacs
Sandra
I’m not aware of GABA or theanine being an issue with esophagitis but it would be best to check with your doctor. Using the amino acids sublingually rather than swallowing them or using in water may help avoid adverse effects. I assume you mean Effexor.
Wendy
The tyrosine counters the GABA so it’s not too relaxing in the day. Interestingly many of my clients do like the GABA Calm at night too. Some folks prefer a GABA only or the GABA-theanine combination at night.
I do avoid GABA Calm when someone has melanoma or Graves (because of the tyrosine contraindications)
The title states “in healthy adults”. What are the downsides for using theanine in a healthy 16 year old? Thanks!
Cindy
I have had success with both theanine and GABA in teens and research supports sleep benefits in boys 8-12 years old with ADHD https://www.ncbi.nlm.nih.gov/pubmed/22214254
I also look at all the other culprits – gluten, sugar, caffeine, IBS/SIBO, low serotonin, high cortisol low blood sugar and EMFs/too much screen time in this age group.
I’m 48 and perimenopausal with anxiety, waking up in the middle of the night and night sweats. I also have leaky gut and MTHFR mutation. I’ve tried GABA at night and Magnesium Glycinate and I ended up staying awake all night. I used l theanine with some success but if I tried to take it past 6:30 PM I’d get crazy dreams if I slept at all. Do you find some people have the opposite reaction and if so, any suggestions? Thanks!
Bette
Too high a dose of GABA can cause adverse effects/opposite effects. I start my clients on 125mg and go up from there.
When I hear “48 and perimenopausal with anxiety, waking up in the middle of the night and night sweats” I think possible low GABA, low serotonin, high estrogen, high cortisol and pyroluria. This blog may help https://www.everywomanover29.com/blog/i-have-issues-with-perimenopausal-anxiety-a-couple-of-weeks-per-month-and-dont-want-to-turn-to-ssris/
Try magnesium l-Threonate. Mercola has a great brand. Made a massive difference for me.
Am taking theanine 50 mg 10:00 and 10:09-11:99 pm. For sleep. As I wake in middle of night. No prob falling asleep. Can theanine be taken indefinitely? Like the dopamine effect of it. Still waking 1-2
Lynne
There is no long-term research on using theanine so we just don’t know. The research reports 200-400mg and we see this to be a good dose clinically – this can prevent the waking but I also consider low blood sugar, high cortisol and low serotonin. We also check for EMF exposure.
I love Gaba and l theanine .
But l theanine works better for me. Just wondering how much I can take a day. Currently I am taking 200 mg twice a day.
Can I take 3 times a day?
Thank you
Barbara
The research indicates 200mg twice a day but I’ve had clients use more, always starting low and increasing based on symptom resolution
I Have been taking Research Nutrition L-Theanine for a while now. I have increased my dose from 1 scoop to 2 because i had run out of my herbal sleeping tablets. It’s been working better than i expected. But i tried Tyrosine for the first time for my fatigue and brain fog. I followed directions, 1 metric teaspoon but i felt like a had 2 large full strength coffees and a Sudafed. Would GABA be better to try instead? I generally am sensitive to high doses of some nutrients or supps and drop doses in herbal tinctures
Hello i take tryptophan, gaba and magnesium byglicinate at night to sleep. I am in menopause so i rub progesterone cream on the bottom of my feet that really works well for me to sleep thru the night without waking up. I take tyrosine and theanine in morning on empty stomach to relieve my anxiety.
Trudy thanks for this info. I always appreciate your studies of medical publications to generate useful tips and info for our health. Coming from a generation above your age I seeing a lot of terms never discussed or seen in the previous century. With all the issues involving the gut, like SIBO, IBS, anxiety, etc. and a seemingly sudden rise in auto-immune diseases…IMOO, I am wondering if something else is going on with our health, perhaps in our food supply, that we are failing to understand.
I use liposomal GABA for insomnia and Bach Cherry Plum for anxious moments. I think I spend most of my days in a para-sympathetic mode but the occasional “reactions” that send me quickly into my sympathetic mode which I hate. I hate the “feelings” of nerves on edge and the seemingly inability to just stop the emotions and to control my mind.
PS- Trudy, IMO your interviews are among the best, since you are usually better prepared than your guest and ask potent and penetrating questions.
I would like to try theanine for sleep problems, anxiety and frequent panic attacks. Right now I take an ADHD medication, Concerta a time released Ritalin, 27 mg. in the morning and 18 mg. in the afternoon. Will there be any interaction between theanine and Concerta?
Arleen
I’m not aware of any reactions but it’s always best to discuss with the prescribing doctor or pharmacist
Hi Trudye,
I have had sleep issues for as long as I can remember. I am now 56 years old and for the past 6 years, it has gotten brutal to say the least. I have a terrible time falling asleep and staying asleep. I find myself waking up between 12 midnight and 3:00 am every single night! I have tried almost every sleep aid there is out there and nothing seems to work. Sometimes they work in the beginning but then they stop working. When I started following you, I started to take the Lidtke tryptophan, gaba, and L-Theanine. They helped in the beginning but they seem to have stopped working for me. I find myself waking up between midnight and 3:00am, fully alert, drenched in sweat and my heart pounding, along with a chattering mind! Last night was the worst because it seems like I didn’t get any sleep at all! Could I be taking the supplements at the wrong time? I take all of them in the evening and because I noticed that I’m a slow metabolizer/digester, I try to take them at 7:00 pm. I am at my wits end and feel like nothing can help me! Please help!
Trudy, so sorry for misspelling your name! 🙂
Andrea
Sorry to hear about the lack of sleep. Chattering mind is typical of low serotonin and/or low GABA and often more is needed and using them during the day too and/or when waking. When someone is having nightsweats we also look at high cortisol, sex hormone imbalances and parasites.
Trudy, have you had experience with clients who are on mental-health prescriptions and taking L-Theanine? I would love to get off these three prescriptions gradually.
Or is there something else you would recommend for me? (I am 79 years old.)
Catherine
When working with clients one on one we always looks at their prescription meds and I have them discuss possible interactions with the prescribing doctor.
I think the missing link in all this is magnesium. I have gotten great relief by adding a product called Remag starting slow and getting up to 3 teaspoon a day alone with GABA I think it’s making a real difference.
Tammy
I agree, low magnesium must always be addressed as must any nutritional deficiency. Glad this and GABA is helping you
i can’t swallow the size of magnesium pills so is remag a powder?
I am very interested to hear that too high a dose of gaba can have the adverse effect. I had a very bad reaction to it once and my nutritionist at the time said it’s very rare but sometimes people turn gaba into glutamate? I would love to know your thoughts about this as I am unsure whether to try it again. I was taking no more than 125mg a day.
Thank you for all your information!
Rosie
It’s glutamine that can sometimes convert to glutamate but mostly converts to GABA. But too much GABA can increase anxiety, cause flushing and light-headedness. 125mg is a typical starting dose (2 or 3 x day) but my pixie dust clients start with much less and slowly build up. Adverse effects can also happen when someone doesn’t need GABA.
Have you ever (or, would you) recommended L-theanine for children? If so, what dosage would you recommend?
Natalie
I have used mostly GABA with children but my colleague and pediatric psychiataric NP likes to use theanine. There are some nice low dose chewables of 50mg available and these tend to be a good starting point (depending on age)
what would be a good chewable theanine ?
Have been taking Zopiclone prescription sleep medication for a year. Cannot fall asleep and stay asleep. What would you suggest as an alternative? Unfortunately Gaba not available in NZ! Anxiety also major issue.
Sher
If the insomnia and anxiety is due to low GABA other options include theanine and sometimes taurine and glycine. I also look into low magnesium and herbs like passionflower and lemonbalm. Blood sugar control is key and so is gluten removal, no sugar, no caffeine, addressing SIBO and dysbiosis and EMF mitigation (remove wifi and go wired)
Apologies for the delay in your comment approval and my response. We had a computer glitch where a large number of comments were hidden from view in a spam folder. It mostly affected new folks who were commenting for the first time but it’s hopefully resolved now.
Hi Trudy. I’m wondering if it’s ok to take l-Theanine with Vitamin C or does Vitamin C negate its effects? Many thanks
TT
I have clients take all amino acids away from vitamin C
At about 200mg or so gaba produces a neon like feeling throughout my body and agitation in brain. Doesn’t take long, about 10-15 minutes after dosing and sympoms begin. On another note, have your clients reported, nausea from starting doses of; 5-Htp, theanine, inisotol, or gaba?
John
Too much GABA can cause adverse effects – either too high a dose or if GABA is not low /not needed. I have clients use less if they have low GABA symptoms. More here https://www.everywomanover29.com/blog/how-much-gaba-should-i-use-for-my-anxiety-it-depends-on-your-unique-needs-and-there-is-an-extremely-large-variation-in-dosing/
5-HTP can sometimes cause nausea in the first week
@Trudy. Tapered down from 200m to about 75mg and it seems ok. Based on the quiz and symptoms it seem likely that gaba is disrupted and in absolute need. Wonder if leaky gut from sibo may have bearing on the sensitivity and overraction to gaba and 5-htp? Bases on reactions noted, the power of taking amino acids sublingually is darn clear. Am playing around with combinations of gaba, theanine and triptophan.
Attension to detail and clinical nuance separates your coverage from other practitioners. Far too many physicians focus primarily on biochemistry, broad symptom overlays and what has been echoed before. Entirely excluding the nuance which each individual faces. You are able to cover bases and nuances and clincal wiggle with relative ease and this is one of your strengths.
John
Glad to hear and love that you are seeing the power of taking amino acids sublingually. We all have unique needs and many factors including leaky gut and SIBO can factor into things – it’s not unusual to benefit from tiny amounts of GABA. May I ask how often you use 75mg and how it’s helping? Your story will make a good blog post and I’d love to share it.
I appreciate your feedback and very kind words.
Trudy;
It may be premature to comment about effectiveness. A few more weeks may be necessary to experiment with gaba, 5-htp, theanine and trytophan, before reaching reasonable conclusions. However, the downside of taking too much and sublingual delivery are noteworthy. In prior decades the capsule form did not result in significant changes, positive or negative.
The driving issues in my case are gut related. Sibo was diagnosed in 2015 after cipro was given for a prostate infection but also impacted chronic gut, sleep and brain issues. All symptoms disappeared. Within a week they returned, but the discovery led to a focus on dysbiois, which remains.
Brain and sleep issues have become intense; this is why amino acids have come to the fore. To “manage” downstream issues in the brain and emotional sphere; subsequent to disturbed and traumatized sleep. Amino acids may also potentially reduce mast cell activation in the brain and vagal branch. If this case fits into your post, am eager to contribute.
I mostly follow low to medium oxalates, the Madura English Breaskfast Tea is Medium oxalate, steeped for two minutes. Would this be enough theanine ?
Karen
In order to get therapeutic amounts of theanine (as in 200mg and above) supplementation is needed. There is also caffeine in teas and this can be an issue with many who experience anxiety.
From this paper, Theanine and Caffeine Content of Infusions Prepared from Commercial Tea Samples https://pmc.ncbi.nlm.nih.gov/articles/PMC4787341/ “In case of white tea, the average L-theanine content was 6.26 mg/g, with a mean caffeine concentration of 16.79 mg/g (caffeine/theanine ratio: 3.07). Black tea samples contained a lower amount of theanine (5.13 mg/g) with slightly higher caffeine concentration (17.77 mg/g), therefore, the caffeine/theanine ratio was higher (4.07). Green tea contained the highest amount of theanine (6.56 mg/g) and since the caffeine content was comparable with the values of the previous samples (16.28 mg/g in average), the caffeine/theanine ratio was remarkably lower (2.79).”
I have had problems staying asleep for years and then I had surgery and my Dr prescribed my GABAPENTIN. It has been the only thing that has helped me sleep through the night. I don’t want to stay on this medicine. I have tried almost every sleep aid out there with no success. (Not having tried GABA before) Which of the supplements you suggest, would you recommend I try?
Ann
The best way to determine which amino acids to consider is to do the symptoms questionnaire https://www.everywomanover29.com/blog/amino-acids-mood-questionnaire-from-the-antianxiety-food-solution/ That said low GABA and low serotonin are both very common with sleep issues. I have clients trial GABA or theanine (or a combo) and then tryptophan or 5-HTP one at a time so they can figure out what is helping.
Keep in mind that gabapentin does need to be tapered very slowly and with the prescribing doctor’s approval. There can also be adverse effects/discontinuation syndrome when tapering, as well as rebound insomnia that may be more severe than the initial sleep issues.
My book “The Antianxiety Food Solution” is a great place to start if you are new to biochemical and nutritional approaches – more here https://www.everywomanover29.com/blog/the-antianxiety-food-solution-by-trudy-scott/ With sleep we also consider and address diet, caffeine intake, sugar intake, gut health, adrenals, parasites etc
And the wait list for my GABA Quickstart program if you need more guidance https://www.anxietynutritioninstitute.com/gabaquickstart/